Manual of Practical Cataract Surgery

Manual of Practical Cataract Surgery Manual of Practical Cataract Surgery R Sundararajan MS DO Professor Emeritus ...

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Manual of Practical Cataract Surgery

Manual of Practical Cataract Surgery

R Sundararajan

MS DO

Professor Emeritus in Ophthalmology The Tamilnadu Dr MGR Medical University, Chennai Consulting Surgeon, Madurai City Hospital Madurai, Tamil Nadu, India

Formerly Professor and HOD in Ophthalmology Madurai Medical College, Madurai Professor of Ophthalmology Vinayaka Medical College, Salem PG Institute of Ophthalmology Dr Joseph’s Eye Hospital, Trichy Tamil Nadu, India

®

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Manual of Practical Cataract Surgery © 2009, Jaypee Brothers Medical Publishers All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher. This book has been published in good faith that the material provided by author is original. Every effort is made to ensure accuracy of material, but the publisher, printer and author will not be held responsible for any inadvertent error(s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only. First Edition:

2009

ISBN: 978-81-8448-605-6 Typeset at JPBMP typesetting unit Printed at Ajanta Offset & Packagings Ltd New Delhi

To My Father whose life-long ambition to make me a well-educated individual... and My Mother whose life-long prayers till her death to provide me excellent education... Have provided me the strength to bring out this work

Preface Though many books are already available in the market, I am introducing this book, with a view to simplify the procedures so that beginners can easily learn doing Manual Phaco (SICS). For high volume surgeries, this procedure is the usual choice as it requires minimum instruments and minimum time. When I had an opportunity to visit some Eye Hospitals, I saw students doing planned ECCE with IOL and have either not done or scared to do Manual Phaco. All beginners of cataract surgery are bound to commit mistakes causing complications which can either be easily rectified or the eye is lost. An attempt has been made to avert complications by making the beginners to understand how each and every step produces the desired or undesired effect. To master the technique of Manual Phaco procedure, one has to be thoroughly oriented with the planned ECCE (Extra Capsular Cataract Extraction) with IOL. This is why this section is also incorporated in this book. In addition, capsulorhexis procedure is explained with the help of easy drawings. In case, the Rhexis is smaller or irregular, a rectifying method of the procedure is also furnished in an easily understandable magnified drawings. SICS is a poor man’s Phaco emulsification procedure. If one is thorough with this capsulorhexis and other basic procedures, it would be easy for the individual to start the phaco emulsification procedures and Micro Phaco procedure, which requires costly equipments and more of an institutional procedures.

viii Manual of Practical Cataract Surgery Though various lectures and CME (Continuing Medical Education) techniques and other methods had been instituted at various centres, I have made this contribution which will be useful to understand still more in detail on seeing the drawings. Similarly, a topic on Squint is also incorporated though not inter-related. Most of the Ophthalmologists are interested in mastering the basic techniques of cataract surgeries only, giving least importance to Squint. An attempt has been made in this book to make the beginners understand Squint easily. R Sundararajan

Acknowledgements The main portion of this subject was gathered from the files I maintained from my own surgeries and management of complications after IOL surgeries. I am immensely grateful to Dr Rajasekaran, Chairman, Dr Joseph’s Eye Hospitals, for the great opportunity provided to me to handle plenty of cases of orbit and IOL cases. I am grateful to Dr Nelson Jesudasan, Director, PG Institute JEH, Trichy, for the valuable permission and encouragement to bring out this small book. My grateful thanks are due to my friendly colleagues, Dr Rajmohan, Dr Ramalingam and Dr Shibu, who used to come forward to help me at the time of distress. I am thankful to my close friend Prof K Kannan, who permitted me to use his printing instruments and also his staff Mrs Ramiza for typing. The preliminary drawings were done by me. I am indebted to Shri Jitendar P Vij (Chairman and Managing Director), Mr Tarun Duneja (Director-Publishing), Mr KK Raman (Production Manager) and Ms Samina Khan (PA to Director-Publishing) of M/s Jaypee Brothers Medical Publishers (P) Ltd, New Delhi for publishing the book. I am also thankful to Mr Jayanandan, Senior Author Coordinator (Chennai Branch) who encouraged me a lot to finish my work by his frequent contacts.

Contents 1. How to Prevent Complications in Manual Phaco? ............................................................ 1 2. How to Prevent Complications in Planned ECCE and PCIOL? .................................................... 45 3. Posterior Capsular Rupture—Rent ........................ 65 4. Capsulorhexis in Detail ........................................... 79 5. Understanding the Basics of Strabismus ............. 91 Index ........................................................................... 121

How to Prevent Complications in Manual Phaco? CHAPTER

1

1

How to Prevent Complications in Manual Phaco?

COMPLICATIONS IN MANUAL PHACO (SICS) The following are the usual complications seen during manual phaco (SICS) procedures: 1. Exccentric position of the globe due to incorrect eye fixation (Bridle sutures) (Superior Rectus fixation). 2. Scleral bleeding due to fixation with colibri forceps. 3. Endothelial and epithelial damage or perforation during tunnel making. 4. Iris prolapse during side port incision. 5. Posterior capsular rupture during BSF injection. 6. Vitreous disturbances. 7. Nucleus sinking or drop. 8. Iridodialysis. 9. IOL drop into vitreous. “Prevention is better than cure” is the usual proverb which everybody knows. Hence, the operative procedures are adopted keeping in mind the proverb. MANUAL PHACO—SICS (SMALL INCISION SURGERY) —HOW TO PREVENT COMPLICATIONS? Though manual phaco is not a difficult surgery in principle, one has to be very careful enough to face the complications which are difficult to tackle and hence, there is a need to form certain basic principles to prevent the same.

2 Manual of Practical Cataract Surgery Pre-Requisites • • • • • • • • • •

A good microscope with an excellent illuminations. A well trained assistant. A sharp unmovable crescent knife. A good straight fixation forceps or straight colibri. A free visco elastic substance in a freely flowing syringe(preferably glass syringe). Sharp blade or No. 1 - Baud parker knife. A good wet field cautery. A well dilated pupil with Tropicamide and Phenylephrine combined drug. Keep the preferred IOL ready with correct power calculation. A spare Anterior chamber IOL also with correct power.

ANESTHESIA AND ANALGESIA Peribulbar block with an excellent massage of eyeball by balancing weight or super pinky ball. The purpose is that the eyeball should be made very soft and immovable. This appears to be safe, ideal and satisfactory method for a successful surgery, though there are other methods. Procedure • When the eye is perfectly blocked, painting of the eye by povidone and instill the same drops into the conjuctival sac. • Wash with BSF after a few minutes. • Speculum is placed.


3

SUPERIOR RECTUS FIXATION; BRIDLE SUTURE (FIG. 1.1) This is one of the important steps in surgery. • Correct placement of bridle suture is mandatory. When this is correctly done, the eye is depressed and that an ample working space is available for conjunctival cautery, incision and mainly to create a tunnel by the angled crescent knife comfortable. • If right half of SR is caught, eye will deviate to right side and similarly into the left side. • If superior oblique muscle is also caught, eye will plunge eccentrically making the produre difficult. • If conjunctiva is caught, there may be a tear of conjuctiva and the eye will be in the primary position. The working space for tunneling with crescent knife will be reduced leading on to the following complications. • Faulty incision —'Unnecessary bleeding while making incision and tunneling. • Insufficient space for tunnel making, followed by all difficulties like: • A. Premature entry: • B. Iris prolapse or ciliary body prolapse, Iridodialysis, damage to upper zonules of lens. • C. Vitreous disturbance.

Fig. 1.1: Bridle suture well including spare conjunctiva on either side

4 Manual of Practical Cataract Surgery CONJUCTIVAL INCISION

Figs 1.2A to C: Conjuctional Incision

The fornix based conjuctival flap with radial cut at temporal side on right side or nasal side in left eye is made as shown in the figure 1.2. It is better to do always on Right side even for left eyefor a comfortable approach. From radial cut, extend with conjunctival scissors upto 1 or 2 O'clock. A minimal cautery on the sclera is applied, where you are going to make incision (Fig. 1.3). It is better to avoid using cautery at the limbus to preserve the Stem cells. It is also essential to preserve the Tensons capsule while cauterising, as the same may be useful to catch and fix the eye while performing tunnelling. The cautery with wet field cautery is always better.

Fig. 1.3


5

SCLERAL INCISION : (UNDER LOWER MAGNIFICATION) (LIMBAL INCISION) 0.4 X OR 0.6 X. There are three types of incisions. 1. Curvilinear incision (Parallel to limbus).

Figs 1.4A and B: Curvilinear incision

2. Horizontal or Linear incision

Figs 1.5A and B: Horizontal or linear incision

3. Frown incision

Fig. 1.6: Frown incision

For the beginners the First Incision is better whereas frown incision is better for experienced surgeons.

6 Manual of Practical Cataract Surgery TUNNEL MAKING • The basic principle is step incision which acts as a valve.

Fig. 1.7

• Make a slight vertical incision first, with ordinary blade.

Fig. 1.8

• Then, incision which is parallel to the layers of stroma with side to side movement of crescent knife to separate the stromal bundles is done. • Some do more oblique incision by holding the blade as we catch a pen during writing so as to reach the stromal portion of the sclera, leading on to the stromal tissue of cornea upto 1-2 mm inside the cornea then by elevating the first incision by crescent knife and then introduce crescent knife to separate to layers.

Figs 1.9A and B

In hypermetropia, the sclera is thick. In myopia, the sclera is thin. Though, it is difficult to know on the table, it can be approximately understood by the following methods.


7

1. The effective IOL power is below 20 for PC after careful IOL calculation. It may be a myopic eye. 2. When the AP diameter is high in 'A' scan picture. 3. In old and healed case of scleritis especially intercalary staphyloma the sclera may be thin. 4. Remember the eyeball is a round globe over which we have another dome of cornea. So the movement of the crescent knife blade should be parallel to the curvature of the sclera, limbus and cornea into the stroma tissue.

Figs 1.10A and B

• After making a vertical incision catch hold of the outer lip of sclera towards limbus, insert the crescent knife into the stromal tissues, separate the stromal bundles parallel to the surface of the dome of cornea by side to side movement of crescent knife upto 1-2 mm into cornea. • While doing this, be careful enough not to deviate the curvature of dome, otherwise there will be button holeing either through the endothelium or epithelium. • Further one can always expect that there will always be an up and down movement of the head of the patient due to poor co-operation which creates the same problem. Sometimes, there will be descemets detachment. • While making crescent knife tunnelling, there will be movement of the head and eye normally. So it is necessary to fix the eye. • Fixing the eye with the colibri on the sclera will produce unnecessary bleeding.

8 Manual of Practical Cataract Surgery

Fig. 1.11

• So it is better to catch either the tenons capsule near the superior rectus with a collibri forceps or press the globe with the dry cotton bud which will absorb the blood at 2 O'clock. • When the bud becomes wet, the grip slips away. Always use a fresh dry buds and proceed side to side movement of tunnelling. • Start the tunnelling incision from left side first with side to side movement of sharp crescent knife upto right side and finish off this procedure at left side again. This is for operational convenience.

Figs 1.12A to C

• Do this procedure as quickly as possible keeping in mind about dome curvature of the cornea.


9

Fig. 1.13

• Another operational convenience is to make the major portion of the Tunnelling incision in the right side of the eye.

Fig. 1.14

• Temporal side incision is also practiced by sitting on the temporal side of patient.

Fig. 1.15

SIDE PORT INCISION This incision can be made at any place. • If incision is made at limbus, there is an immediate gush of aqueous out, making the anterior chamber shallow subsequently producing iris prolapse. • In case without our knowledge the incision is deep, there is a chance of iridodialysis, tear of zonules, leading on to disturbance to vitreous face.

10 Manual of Practical Cataract Surgery • Prefereably in case, the side port incision is made at 6 O'clock position of limbus, it makes the further procedure difficult by iris prolapse. Whether it is at limbus on inside cornea.

Fig. 1.16A and B

• So, it is better to make S.P.I (Side port incision) at 8 or 9 O'clock position 1 mm inside the limbus i.e., in the cornea. • This S.P.I also should be a step incision to act as a valve and self-sealing.

Figs 1.17A and B

• When we are using a big angled keratome, the breadth of the incision is more and so there is a chance of leak of aqueous once the surgery is over. • So, it is better to make an incision smaller so as to admit the tip of 26 G needle for injection of air or Trypan blue dye. • In case a pterygium is present, it is preferable to avoid and make S.P.I below the margin of pterygium.


11

Fig. 1.18

• When you make a S.P.I, it is better to catch the opposite, side limbus or sclera and fix it with toothed forceps or colibri and then introduce S.P.I blade or angled keratome.

Fig. 1.19: Fix at opposite side.

The purpose of S.P.I is to aspirate the 12 O'clock position cortex, through this hole. When once the S.P.I is done, anterior chamber becomes shallow. Fill the anterior chamber immediately with air or Viscomet with blunt 26 G needle. While introducing the needle for air injection, there is always a chance of damage to anterior capsule. So the procedure should be quick and damage free.

Figs 1.20A to C

12 Manual of Practical Cataract Surgery Once the air bubble is injected into anterior chamber and A/c is formed, the trypan blue dye may be injected under the air bubble and smear the anterior capsule with the dye. BSF wash is subsequently given to wash the dye and then fill the chamber again with the Viscomet to push the air out.

Fig. 1.21

If you are confident of washing 12 O'clock cortex without S.P.I, you can skip this procedure and similarly the dye also. Once the surgery is over, S.P.I can be closed by injecting intralamellar BSF, if necessary. Now the surgeon can open the sclerocorneal incision and open incision at 10 - 12 O'clock position to make anterior capsulotomy. Inject viscomet immediately to fill and to prevent shallowing of anterior chamber. CAPSULORHEXIS; (UNDER HIGH MAGNIFICATION) 1.0X OR 1.5X Bend the 26 G needle a little bigger than suggested in planned ECCE where it is ½ mm 45° - 60°

Fig. 1.22


13

Here the purpose of bending the needle is not only to cut the anterior capsule but also to push the capsule towards the center while making a 5 mm size circular incision with the tip of the bent needle. The dyed anterior capsule appears blue.

Fig. 1.23: This portion of anterior capsule is elevated and separated.

Inject viscomet into anterior chamber. Now, introduce the bent needle through the sclerocorneal incision, horizontally to avoid damage to endothelium of cornea or anterior capsule of lens and then rotate anti, clockwise. Start from the centre i.e., tear the capsule at the centre in a curved fashion. With the tip of the needle, push the capsular free edge, close to the junction and tear. Make a gentle pushing with the direction towards the centre, slowly millimeter by mellimeter till you achieve a circular rhexis with clear border. This can also be achieved using Mcpherson forceps or Utratas forceps by simple tearing circularly the free elevated end of capsule. Make a oblique C-shaped incision at the centre of lens capsule. The elastic capsule recoils as shown in the picture. The curvature 'C' is to create circular linear tear and to create a free border of capsule to fold. Fold the free edge of the capsule.

14 Manual of Practical Cataract Surgery CAPSULORHEXIS

Figs 1.24A to H: Capsulorhexis

CAPSULORHEXIS WITH 26 G NEEDLE (BENT) MAGNIFIED.

Figs 1.25A to H: Capsulorhexis with 26G needle


15

Then, slightly elevate the capsule and push the folded border of the free end of the capsule in such a way to create a circular tear as shown in the figure. The difficulty arises when the bent needle pushes the anterior lens capsule to tear at left side - 3 O'clock position. The problem can be solved by meticulous, patient handling. The ideal way to learn is by practicing the same with a red tomato or sapota fruit (chippu). You are at liberty to make a can-opener method and proceed, instead of rhexis. The advantage of this rhexis is to avoid the unnecessary tags of capsule. Big or wide rhexis is always better for manual phaco procedure. In small rhexis, when the BSF is injected under the capsule for hydrodissection the BSF stays in the posterior pole to form a pool and finds it difficult to create a wayout and so it creates a posterior capsular rent followed by vitreous disturbances.

Fig. 1.26

In case you make a bigger rhexis, fluid easily finds its way out and does not pool in the posterior capsule.

Fig. 1.27

16 Manual of Practical Cataract Surgery HYDRODISSECTION Inject 1 cc of BSF under the cut edge of anterior capsule at the periphery at 6 O'clock to 9 O'clock. This produces the separation of posterior capsule from the cortical fibers and raises the nucleus slightly above and floats.

Figs 1.28A and B

EXTENTION OF INCISION After filling the Anterior Chamber A/c with Viscomet the small wound in the corneo-scleral incision at 11-12 O'clock position may be extended with the help of wound extension blade or angled keratome on either side of the wound so as to allow the easy delivery of nucleus. For this, the wound extendor is comfortable.

Fig. 1.29

As the incision is small the wound may be extended inside only on either side, the inner C.S opening should be bigger than the outer side C.S opening.


17

Figs 1.30A and B

MANUAL ROTATION OF NUCLEUS

Fig. 1.31

In each and every step of the procedure, you should not fail to notice the anterior chamber becoming shalow. When it becomes shallow, it produces endothelial damage, so you have to inject then and there sufficient Viscomet to prevent endothelial damage to cornea. Now, inject BSF under anterior capsule after a successful Rhexis at 5-6-7-8 O'clock position to raise the nucleus above pupil.

18 Manual of Practical Cataract Surgery NUCLEUS DELIVERY

Fig. 1.32

Once the hydrodissection is done, inject viscomet into anterior chamber with the help of nucleus dialor (IOL Dialor) engage the tip of dialor a 7 to 8 O'clock position of periphery of nucleus near the dilated margin or pupil.

Fig. 1.33

Rotate the nucleus in a clockwise pattern while gradually raising and elevating the nucleus, so that the equator of the nucleus is tilted up and appears well into the anterior chamber. After having seen the equator or nucleus in anteiror chamber the nucleus is slightly tilted.


19

Fig. 1.34

Now engage the under surface of the nucleus near the equator and rotate in an anti, clockwise manner, till the entire nucleus comes into anterior chamber.

Figs 1.35A to C

No, inject viscomet both above in anterior chamber and below the nucleus.


Fig. 1.36

During the entire procedure, inject viscomet, sufficiently to keep anterior chamber well formed. During the first clockwise rotation procedure, if the nucleus does not appear into anterior chamber easily, or if you see that the nucleus recoils back into its original position, it signifies that there is an 1. Adhesion or 2. Small pupil (undilated). 3. Small rhexis. Adhesions

Fig. 1.37

In case, you are not able to locate the cause of recoil, i.e., the site of adhesion, it is better to avoid unnecessary venture, do the well practiced procedure, planned ECCE and nucleus delivery by squeezing the equator of the nucleus out. – If insufficiently dilated pupil = there is posterior synechia. – If you notice a dimple at the centre of iris, there is adhesion at the mid position of iris. – If recoils or a pull is noticed at the pheriphery, then there is adhesion at the periphery. – If you are able to locate the posterior synechia release with iris repositor. – Otherwise, you are likely to rupture the posterior capsule and allow the nucleus to sink.


21

Caution It is always better not to allow the nucleus to sink into vitreous. SMALL RHEXIS This may also be due to small rhexis. The diameter of normal rhexis is 5 mm. If you make a slightly wider rhexis, (about 6 mm) the nucleus rotation and nuclear delivery also is easy, (The reason behind is already mentioned) Once small rhexis is already done, the relaxing incision of anterior lens capsule will be helpful. Make an incision at ALC at 5 and 8 O'clock position or at 12 O'clock position alone.

Figs 1.38A and B

ALC - Anterior lens capsule. SMALL PUPIL (UNDIALATED) In Px syndrome or iris adhesions due to uveitis, pupil may not dilate. Under such conditions, try to release the synaechia, by sweeping with iris repositor all around through the pupil. Or do a key hole iridectomy (i.e., make a P.I, at 12 O'clock posistion. Then by introducing one edge of scissors though the P.I upto pupil and cut it.


Fig. 1.39

Now dial up the nucleus into anterior chamber after making the nucleus to enter into anterior chamber fully, it is your duty now to deliver the nucleus out. NUCLEUS DELIVERY Inject plenty of viscomet under the nucleus and above the nucleus. Now by introducing the viscomet needle upto 6 O'clock position, inject viscomet, more and allow the nucleus to be drifted out automatically by slightly depressing the posterior lip of sclera.

Figs 1.40A and B

If the corneo, scleral incision is slightly bigger the nucleus automatically finds its way out by the viscomet pressure. If the C.S incision appears small inject some viscomet then extend the inner incision on either side slightly and


23

try the same procedure or do any one of the following method.

Figs 1.41A and B

a. Sandwich method. b. Irrigating Vectis method. c. Cut the nucleus into two and deliver each bit separately. Sandwich Method Inject viscomet under the nucleus and above the nucleus into anterior chamber. Pass the vectis below the nucleus and nucleus rotator above the iris upto 6 O'clock position till the equator is engaged in vectis. The nucleus rotator should be placed over the anterior nuclear border near 6 O'clock position of equator of lens. The hook portion should be placed horizontally so that it does not touch the endothelium of the cornea.

Fig. 1.42

24 Manual of Practical Cataract Surgery And sandwiching the nucleus on either side. Now, gradually drag the nucleus out, so that it does not touch the endothelium at any point in a curved fashion, gradually pulling out and up towards the surgeon.

Fig. 1.43

If the C.S tunnel is slightly bigger try injecting viscomet at 6 O'clock postion of anterior chamber, allow the entire nucleus to be drifted out automatically, depressing the posterior lip of tunnel with the same viscomet cannula. During the delivery of nucleus, it is likely, without the surgeons knowledge, that the surgeon may introduce vectis under the iris through the pupillary border at 6 O'clock position and pull the iris also out, along with the nucleus i.e., either partial or total iridodialysis. So to avoid, carefully see that the vectis is passed under the nucleus through the transparent semi-cataractous nucleus. This is visible in microscope. Or even at 12 O'clock position by creating a partial dialysis at 12 O'clock position.


25

Figs 1.44A and B

IRRIGATING VECTIS METHOD There is another method of delivery of the nucleus. the device is called Irrigating vectis. This consists of three small holes at the vectis portion of the syringe needle. The needle tube extends all around the vectis (Figs 1.45A and B).

Figs 1.45A and B

The needle is attached to BSF fluid tube directly or the tube needle directly mounted on the syringe loaded with BSF fluid (Fig. 1.4.5). This depends on the convenience of the surgeon.

Figs 1.46A and B

26 Manual of Practical Cataract Surgery The Method After the hydrodissection, and once the nucleus is rotated and brought out into anterior chamber. Fill the anterior chamber with viscomet (Viscoelastic fluid ) both above and below the nucleus. The posterior capsule is situated under the iris diaphragm.

Fig. 1.47

Now, introduce the irrigating vectis through the limbal opening, without the flow of fluid, under the nucleus into the anterior chamber, so that the concave surface of the vectis engages the under surface of nucleus upto the equatorial position.

Fig. 1.48

Now, open the valve in the BSF dripset, so that the BSF flows well into the anterior chamber. The fluid pressure pushes the nucleus out and simultaneously drag the nucleus out. 1. Fluid pressure pushes nucleus out. 2. Hook the nucleus out. 3. Depress the posterior scleral lip so that nucleus comes out easily.


27

Fig. 1.49

The precautions to be taken are: The freely flowing BSF fluid should not be directed towards the posterior capsule, as this procedure may rupture the posterior capsule and the anterior vitreous face causing vitreous disturbance.

Fig. 1.50

While introducing the irrigating vectis, with the BSS fluid flow is on, may hit the endothelium of the cornea and damage the endothelial cells.

Fig. 1.51


Fig. 1.52

While introducing the vectis there is a chance of Descemets detachment when the anterior chamber is shallow. So fill the anterior chamber with visc first, making anterior chamber well formed and then start the procedure.

Fig. 1.53

The following are the expected complications: 1. When the nucleus is densely cataractous, it may obstruct the view of irrigating vectis passing under it. As a result, there is a chance of the vectis passing under the iris diapharagm upto the root of iris. In this manoeuvre, there is a chance of creating irido dialysis at 6 O'clock position.

Figs 1.54A to C


29

2. In case direction of the irrigating vectis is more oblique and tilted towards 6 O'clock position, there is a chance of the irrigating fluid to flash through the posterior capsule and anterior vitreous face and disturbing the vitreous.

Fig. 1.55

3. While introducing the vectis, if the fluid has already started flowing, there is a chance of damaging the endothelium of the cornea, when fluid hits against it.

Figs 1.56A to H

30 Manual of Practical Cataract Surgery 1. Fluid pressure pushes nucleus out. 2. Hook the nucleus out. 3. Depress the posterior scleral lip so that nucleus comes out easily. EPINUCLEUS DELIVERY After the nucleus delivery, there will always be a bulk of epinucleus left over at the anterior chamber, which will be seen as a hazy media. This can be cleared by injecting viscomet again into Anterior chamber introducing the viscomet cannula at 6 O'clock position of the periphery and see that the remaining epinucleus is drifted out, by pushing viscomet. Remember to depress the posterior lip of wound by the same cannula, so that the epinucleus finds its way out easily. Some surgeons prefer to syringe out using BSF in the cannula.

Fig. 1.57

In my experience the injection of viscomet does a good clearing. When once this procedure is over, the media appears still slightly hazy, due to the remaining cortex. This can be well washed with BSF in the 21 G cannula or 22 G needle and aspirate.


31

For the Beginners It is better to use the 22 G cannula needle to aspirate this thin cortex. This takes a little time to aspirate. For a quick washing of cortex use of 21 G needle Cannula with BSF is better. This is possible only with some experienced surgeons. The method of syringing the cortex has already been discussed. INSERTION OF IOL Fill the anterior chamber once again with viscomet. Introduce the IOL of your choice into the anterior chamber and then in between the anterior and posterior capsule at 6 O'clock position in such a way that the dialor, when engaged, can rotate the IOL clockwise, i.e. the lower haptic curvature should be facing left side.

Fig. 1.58

Before doing this procedure perform the following procedure. a. Catch the upper haptic with the Mcpherson or IOL lens holder.


Figs 1.59A to D

b. Remember the possibility of creating a damage to the surface of the optic when engaging the IOL with Mcpherson or lens holder. c. Wash the IOL with distilled water on both the sides and then smear the IOL with viscomet on both sides to avoid damage to endothelium of cornea. After having placed the IOL in position, wash the IOL with BSF and the anterior chamber. Closure As the incision is smaller, the approximation of both the corneal lip and scleral lip is perfect as it is a step incision. This does not require suturing. CONJUNCTIVAL CLOSURE Bring the conjunctiva to its original position. Catch the both ends (vertical) as shown in the picture and using wet field cautery, inside BSF and cauterise.


33

Figs 1.60A to C

While cauterising, catch the base (lower) position of conjunctival flap and cauterise under BSF.

Fig. 1.61

INTRAOPERATIVE COMPLICATIONS AND HOW TO TACKLE IT Iridodialysis 1. If it occurs at 6 O'clock position inject viscomet in anterior chamber to push the flap back. When you see that the flap is nearing limbus, carefuly catch the free end of iris, start suturing, take the first bite at 6 O'clock position at the limbus as shown in the picture. 2nd bite at the root of iris. 3rd bite at 6 O'clock position of the cornea and suture with 8 or 10 suture.

Figs 1.62A to C

34 Manual of Practical Cataract Surgery If necessary two more sutures, one on either side.

Fig. 1.63

2. When the iridodialysis is at 11-2 O'clock position take the 1st bite at sclera take out, then 2nd bite at root of iris, take out and then 3rd bite at the cornea and suture or vice versa.

Figs 1.64A to D

Nucleus Sinking This should not be allowed to happen - this is a dreaded complication. In case nucleus starts sinking, put a stab puncture at pars plana with 24 G needle at 7 O'clock position or at a


35

suitable position, push in the needle under the nucleus, make the nucleus float. Ask your assistant to push up the nucleus carefully, quickly introduce the Macpherson, catch either the haptic or optic or nucleus and pull out.

Figs 1.65A and B

After having removed the nucleus out, have a look at the pupil to find out where the vitreous is peeping out. Pupil will be peaking at one place as shown in picture.

Figs 1.66A and B

HALF NUCLEUS DELIVERY Vectis should be passed under the nucleus upto the equator and the nucleus dialor should also be at the same place engaged similarly to bring out in full. Sometimes, if you engage the nucleus at the centre with both the vectis and the dialor, it is likely that only one half of the nucleus alone comes out breaking the nucleus into half.


Fig. 1.67

The remaining half of the nucleus will be retained in the anterior chamber. In such circumstances, it is better to inject viscomet at 6 O'clock position of anterior chamber which forces the remaining nucleus to be drifted out. In case it is not possible, engage the nucleus again with vectis and nucleus dialor and pull out. Now introduce Vannas scissors cut the vitreous at the pupillary border, make the pupil round or circular or inject pilocar or acetylcholine to make it round and reconstricted. Inject air to reform the anterior chamber put in anterior chamber IOL. Do peripheral iridectomy and close. When once the nucleus is sunk. Abandon the surgery and leave it to retinal surgeon.

Figs 1.68A and B

Catching the IOL at the optic surface will produce scratches or rough surface on IOL. It is always better to catch the haptics.


37

DESCEMETS DETACHMENT IN SICS There is a chance of descemets and endothelial detachment and hanging into the anterior chamber giving a false impression. When any instrument is introduced through the step incision. At this circumstances the surgeon has to understand that the descemets -endothelium complex in the scleral side is projecting, whereas the same in corneal side is far behind, concealed and out of direct view. Anterior chamber may be shallow. The surgeon has to be more careful and deal without excitement. It is better, he removes the nucleus quickly by some uncomplicated method and insert the IOL, wash with BSF to remove cortex. The purpose is to proceed without complicating it anymore. Now fill in air in the anterior chamber to push back the descemets and endothelium complex in its original position. Reform anterior chamber and if necessary, limbal suture may be placed to keep the descemets complex well reapproximated in the post operative period.

Fig. 1.69

Remove nucleus quickly, wash the cortex.

Fig. 1.70

38 Manual of Practical Cataract Surgery WHEN THE PUPIL IS NOT DILATED. As in pseudoexfoliation syndrome or in iritis. Sweep the iris with iris-repositor through the pupil all around. Break the synechia. Some surgeons dilate the pupil by dialors by keeping it in opposite direction and dilate, sometimes tear occurs.

Fig. 1.71

Some make one cut at 5 O'clock and 8 O'clock position at pupillary border which is not sufficient.

Fig. 1.72

My opinion is to make a peripheral iridectomy at 12 O'clock position then vertical cut make a keyhole iridectomy. This produces sufficient dialatation, pull out iris at 12 O'clock position, suture the pigmentary epithelium side and put it back (after introducing the IOL).


39

Fig. 1.73

IN DIABETES AND OLD AGE There is always a possibility of iritis and choroiditis, posterior synechia. Under such condition, dialing or rotating the nucleus is not possible. In our attempt to dial, the nucleus becomes suddenly vertical, producing posterior capsular rent. Find out where the rent is? Find out whether the vitreous is above or below the nucleus, use a cotton bud and pull, see whether the pupil distorts. In such circumstances, cut the vitreous at the pupillary margin and prevent sinking of nucleus by passing 24 G needle at pars plana below the nucleus, lift the nucleus up with the help of Mcpherson forceps-remove the nucleus. For a beginner the success of the surgery depends on 1. Correct superior rectus fixation 2. The sufficient pupillary dilatation, and 3. A procedure to prevent sinking of the nucleus by any means.

40 Manual of Practical Cataract Surgery WHEN WILL YOU INJECT VISCOMET INTO ANTERIOR CHAMBER? The principle is • To avoid injury to the endothelium of the cornea. • To clear the hazyness of the cornea put a drop on the cornea. • When anterior chamber is opened inadverdantly or without our knowledge during surgery. • During incision when anterior chamber is opened. • Side port incision (S.P.I) immediate gush of aqueous inject viscomet to reform anterior chamber or if you want to inject dye, inject air. • After injecting trypan blue dye-inject viscomet to reform anterior chamber. • When C. S incision opened aquous comes out. Inject viscomet to reform anterior chamber. • Before making anterior capsulotomy- inject viscomet. • After making anterior capsulotomy - inject viscomet. • Before injecting BSF under anterior capsule to separate. • Before using dialor for nuclear rotation. • When rotating the under surface of the nucleus at its equator. • When once nucleus comes out into anterior chamber. • Inject at 6 O'clock position of anterior chamber to drift out nucleus when incision is bigger simultaneously depressing the posterior lip of sclera. • Before introducing the vectis under the nucleus and dialor above. Inject viscomet both above and below the nucleus. • After the nucleus is out reform anterior chamber with viscomet and also at 6 O'clock position to push the epinucleus out. • Before aspirating the remaining cortex. • Before introducing the IOL.


SUMMARY FOR MANUAL PAHCO

Conjunctival incision

Side port

Figs 1.74A to Q

Incision

41


Figs 1.75A to K


NUCLEUS ROTATION

Figs 1.76A to E

NUCLEUS DELIVERY

Figs 1.77A to C

43


Figs 1.78A to D

Figs 1.79A to C

How to Prevent Complications in Planned ECCE ... 45 CHAPTER

2

How to Prevent Complications in Planned ECCE with PCIOL?

This portion is specially included for-this method is still practiced in most of the centres and is also a basic for the advanced procedures. Secondly, in case of failures in manual phaco or micro phacos one can quickly change over or convert it to this method to restore the vision rather than dealing unnecessarily with complications. So it becomes absolutely essential to master this basic method to restore vision to the patient. COMPLICATIONS The following are the usual complications that can occur during surgery: 1. Retrobulbar hemorrhage. 2. Wound gaping. 3. IRIS prolapse and infection. 4. Descemets detachment 5. Endothelial damage—leading to striate Keratitis in the post-operative period. Retrobulbar Haemorrhage For local analgesia-peribulbar analgesia followed by massage by placing a balanced weight or with or without facial analgesia.

46 Manual of Practical Cataract Surgery Retrobulbar injection of 2% xylocaine, adrenaline and hyalase with 2.5 cm length or 2.0 cm length needles is likely to tear either the blood vessels or pierce into meningeal sheath or damage to optic nerve by entry of the needle. Or double puncture of the globe, in myopic eyes or big eyes. In case, the analgesia expires prematurely, it is advisable to give an injection of ½ to 1 ml of 2% Xylocainesubconjuntivally at 6 O'clock or fornix. During the middle of surgery. To avoid infection it is preferable to use a fresh 2 ml disposable syringe and fresh sterile bottle of 2% Xylocaine. HOW TO PREVENT COMPLICATIONS IN PLANNED ECCE WITH PCIOL? Now, it has become inevitable that all cases who are getting operated should face "SUCCESS" otherwise we are getting into troubles with consumers problems. As such, each step of surgery has become important so that we can be cautious about the possible complications. This is helpful for beginners though it is not much useful for surgeons who performs "small incision surgeries". Basically, the microscope should have excellent illumination, wide field coverage, with good optics. All aseptic precautions should be strictly followed. Including general like dental sepsis, otitis media, ulcers, etc. First exclude diabetes, hypertension, dacryocystitis and glaucoma mainly. Dilate the pupil with Tropicamide and Phenylephrine combined drug. Proper preoperative/Eyelash cutting. Betadine painting, instillation in eye followed by washing.

How to Prevent Complications in Planned ECCE ...

47

Before starting the surgery when the patient is on the table, focus the microscope -with 1.6 magnification bringing the optics on the headside towards the surgeon to bend the 26 guage needle first i.e., 0.5 mm at the tip (small enough to raise only the anterior capsule). Big needle bend ruptures posterior capsule. Viscoelastic substances loaded in advance and kept ready without -air bubbles. BSF or Ringer lactate solution with patent cannula ready. Posterior capsule is thin by 1/5 of the anterior capsule. Tip bending should be small. If it is Long, posterior capsule will rupture.

Figs 2.1A to I

48 Manual of Practical Cataract Surgery SMALL SCLERAL SIDE CAPSULOTOMY IS BETTER. If more central scleral side capsulotomy nucleus has to find a longer way to sweep and come out. In this process nucleus becomes vertical and so damages endothelium of cornea and posterior capsule. Excessive depression with central incision of anterior capsule may itself press and tear posterior capsule causing vitrous disturbance. Perfectly sharp blade (blunt blade produces ragged incision-followed by descemets detachment) should be used.

Fig. 2.2

UNDER LOW MAGNIFICATION After applying the speculum-take a wider bunch of conjunctiva on either side of the superior rectus musclepassing the curved needle under the muscle (since partial bite of superior rectus deviates the position of the eye, to an unwanted position ) by depressing the lower fornix. Conjunctiva is reflected from right side to left side with radial cut at 10 O'clock close to limbus (limbal based ) and extended to 2-3 O'clock left side.


49

Fig 2.3

Figs 2.4A and B

I always prefer to do step incision of the limbus starting at the posterior limbus (towards surgeron). Vertical incision, then horizontal, in the stroma and finaly oblique entry into a/c (vertical entry into a/c may pull down descemets membrance and detachment).

Figs 2.5A and B

The horizontal incision is made with the center portion of the blade following the curvature as it produces separation of bundles of stroma - Tip incision may tear the bundles.


Figs 2.6A and B

Step incision acts as valve and avoids iris prolapse, wound gaping and less number of sutures are enough. Center position Tip |

↓

Figs 2.7A and B

Now, open anterior chamber obliquely with tip of blade at 10.30 O'clock to 11.30 O'clock position -at Pre-descemets level.

Fig. 2.8

Once the aquous starts coming, introduce the Viscoelastic needle with syringe and inject it. Otherwise anterior chamber becomes shallow introduction of instruments will separate descemets membrance.

Figs 2.9A to C


51

If air bubbles are present, push the needle tip upto 6 O'clock position of anterior chamber and inject viscomet (viscoelastic) till the air bubbles are drifted away through the limbal opening at 11 O'clock position.

Fig. 2.10

UNDER HIGH MAGNIFICATION Carefully Watch the Anterior Capsulotomy Margin Introduce the tip of the needle so that bent tip is horizontally introduced parallel to the surface of iris, then tilt vertically down. I prefer to do anterior capsulotomy in "Smiling face technique" - as I find it useful, because-in case a rent at 12 O'clock position occurs, you can notice it easily when the pupil becomes slightly oval or a pull - distorted, after removal of nucleus.

Figs 2.11A to D

52 Manual of Practical Cataract Surgery The anterior capsulotomy should be done towards the scleral side of the capsule. Instead of making anterior capsulotomy by 26 G needle, Smiling face technique, the same can be done with the tip of the blade on a handle to create a linear border.

Fig. 2.12

This incision can be made after fully opening the anterior chamber, subsquently filling the chamber with Viscoelastic substance. The needle anterior capsulotomy produces capsular tags which may disturb the surgeon during aspiration of cortex at 12 O'clock position. By doing knife blade incision, the incision borders are clear cut and there is no capsular tags.

Figs 2.13A to C

Aspiration of capsular tags sometimes produces extension into posterior capsule.

Figs 2.14A and B


53

Smaller scleral side flap is always better, for sliding delivery of the nucleus.

Figs 2.15A and B

Even if anterior capsulotomy is smaller in one stroke, you can extend the same during hydrodissection. Do not repeat. Bigger scleral side flap will take a longer way to sweep the nucleus to come out of capsule. It will produce nucleus becoming vertical, producing damage to endothelium of cornea.

Figs 2.16A to C

Hard nucleus may rupture of posterior capsule and disturbance to patellar fossa and vitreus. Posterior capsule is 1/5 th of the thickness of anterior capsule. Inject viscomet at 10 O'clock position to make it deeper to avoid injury to iris. (Shallow anterior chamber produces cut of iris and sometimes lens matter also).


Fig. 2.17

Extend the incision on either side with curved scissors.

Figs 2.18A to E

Enlarging the incision at limbus will be difficult with scissors. So enlarge incision on either side with end of the blade on blade holder from inside out (anterior chamber should be deeper with viscomet-otherwise whallow anterior chamber may produce cut and shaving of endothelium).

Fig. 2.19

Now, hydrodissection-In multiple injections under the anterior capsules in smaller amounts in different directions.


55

Fig. 2.20

(The bulk injection or 1 cc or 2 cc of BSF fluid may rupture the very thin posterior capsule at the centre)

Fig. 2.21

Deliver the nucleus making pressure at 6 O'clock position with either wire vectis or depressor about 1-2 mms above the limbus in cornea and counter pressure to unsleeve the anterior capsule at 12 O'clock position for easy squeezing and sliding delivery of the nucleus from the equatorial position.

Figs 2.22A and B

Making pressure at the centre of the cornea will depress the central cornea followed by pushing the nucleus down to tear the posterior capsule.


Figs 2.23A and B

Gentle counter-pressure at 12 O'clock position of sclera can be done with another wire vectis or spatula. Pass the cannula with aspiration port above.

Fig. 2.24

Pass the cannula parallel to the surface of the iris, then slightly dip to enter under the anterior capsule and again raise up so that fluid speed is not directed towards posterior capsule.

Figs 2.25A and B

The flow of BSF is sufficient to float the cortex and aspirate from periphery to the center.

Figs 2.26A and B


57

Speed should be adjusted so that anterior chamber should never be made shallow, as it may suck the centre of the cornea, as well as the posterior capsule creating rupture vitreus disturbance. Fluid speed either moderate or a little faster. If bulk of epinucleus is present, depress the scleral side opening' inject viscomet at 6 O'clock position of anterior chamber to push out (kindly refer the topic on posterior capsular rent). Keep always the pupil well dialated to have clear views of the procedure what you are doing. In pseudo exfoliation syndrome, old uveitis with posterior synechia patients, pupil will not dialate. Under such condition, key-hole iridectomy should be done to have a clear view.

Fig. 2.27

One or two drops of adreneline in BSF solution in a 2 ml syringe, if injected may dilate the pupil. Nuclear cataract (brown cataract) will be bigger and harder. So bigger incision and liberal use of viscoelastic material will be needed to protect the cornea. Inject viscomet under anterior capsule and raise it. Fill in anterior chamber.

Figs 2.28A and B

58 Manual of Practical Cataract Surgery When cortex is cleared, IOL should be introduced as per the calculations made by SRK formula under anterior capsule. Catch haptic IOL with Mcpherson forceps with the (angled bent) to the right and the lower haptic to the left so that if introduced, it should rotate clockwise as shown in the figure.

Figs 2.29A and B

If corretly done-and rotated, anterior capsule will be lying over the IOL and raise it with viscomet.

Fig. 2.30

Cut anterior capsule obliquely or curved at 3 and 9 O'clock position - and peel off capsule in the form of rhexis with Mcpherson.


59

Figs 2.31A and B

Wash anterior chamber with BSF Inject Air and then suture. Take full thickness bite, (as the corneal lip contains only Epithelium, stroma) and then another bite at the step-in scleral side with correct approximation.

Fig. 2.32

Needle holder should catch the centre position of the 10.0 suture needle. (If the needle is caught at 1/3 rd end of either side of needle-it may straighten)

Figs 2.33A to C

60 Manual of Practical Cataract Surgery My Suggession to "Smiling Face Technique" Is This Even if a small rent is noticed, vitreous can be raised with cotton bud. Cut with scissors-all around the pupil, put in air - the PC lens can be placed above the Anterior capsule ciliary sulcus IOL. • Yag laser can be applied at a later date if necessary. If nucleus becomes vertical during delivery, inject viscomet both anterior and posterior to lens flatten with iris spatula. If cortex is present at 12 O'clock postion, pull out iris at 12 O'clock position ' aspirate cortex. Cortex should be aspirated - in opposite direction.

Fig. 2.34

At the time of irrigation and aspiration at the periphery -carefully introduce the cannula in between anterior and posterior capsule upto periphery with a slight tilt upwards to make cortex float-aspirate. In case you include posterior capsule -dehiscence occurs. Now discontinue. Inject viscomet-flatten, posterior capsule carefully introduce PC IOL.

Fig. 2.35


61

If analgesia wears off and patient is restless, inject 2% xylocaine ' subconjunctivally at 6 O'clock to relieve pain. Bend the cystitome with the base of needle holder, otherwise the needle holder will get spoiled.

Fig. 2.36

In Can Opener Method

Fig. 2.37

Start anterior capsulotomy at 9 O'clock position and proceed in anticlockwise method as shown in figure.

Fig. 2.38

For safer removal of capsule make multiple vertical and horizontal incisions make it into multiple smaller bits. Aspirate with infusion with cannula. 1. When the pupil is not round → Iris is caught by the haptic somewhere. So rotate-reverse-sometimes vitreous prolapse can also distort the pupil. 2. When there is froth in anterior chamber with air → There is still some viscomet present.

62 Manual of Practical Cataract Surgery Brown black cataract

Membranous cataract

Congenital cataract in children

Posterior capsular opacity

Hard big nucleus

Clear with 7 shape GA with good a/c (small horizontally forming. placed incision)

------

So incision should be big

Needle-scrape make it thin

Good relaxation

No sclerosis

Hard nucleus may produce damage to

Do it with viscomet

PC rhexis is better and insinuate HAPTIC below PC rhexis

Good anterior capsulotomy.

Endothelium Do posterior inject plenty of capsulo rhexis viscomet over if needed the nucleus.

(optic capture) Extract clear IOL power heparin nucleus. treated IOL is better

Deliver the -nucleus by sliding method.

--

If anterior capsulotomy is not enough give a cut like this.

Layer of clear cortex may come in. Wash and allow cortex to peel of thin layer of cortex

CAPSULOTOMY

OR

OR

posterior capsulotomy.

Figs 2.39A to C Do caneopener method

Rhexis is better and anterior vitrectomy.

Scleral side Capsulotomy should be small.

How to Prevent Complications in Planned ECCE ... In cataract

63

Pseudoexfoliation

Immature cataract

Myopic eye cataract

Posterior capsule fragile and do key hole iridectomy or Pupillary margin cut one or two

There will be a thin slice of cortex lying over the posterior capsule run the fluid, raise the cortex → aspirate

Sclera is thin So when you make a vertcal incision -> invariably the ciliary body is seen give peribul bar block after raising the globe with the tip of your finger and supra orbital block after depressing the globe.

Figs 40A and B Lens if deep incision or repeat Incision damages So dialate pupil Well with adrenaline

Raise the Fig. 41 anterior capsule with small bent needle→extend the incision→ infusion. Wisk awy the hard nucleus with horizontally forward pushing stimultaneous capsulo- Fig. 42 tomy irrigation and aspiration with tast fluid flow. Anteriorcapsulotomy Fig. 43

When IOL power is low it is myopic put no deep incision

64 Manual of Practical Cataract Surgery Central SK (Striate Karatitis)

Peripheral SK

Causes Causes 1. If canula hole up→ 1. While introducing fluid hits endothelium instruments without viscomet. Fig. 44 2. Nucleus-hard (brown) if delivered 2. Tip of the hapatic without scraping. 3. Vertical turning of nucleus

3. Blunt blade-ragged incision.

Fig. 45 4. Instruments touching —— the back of the cornea. 5. A/c shallow → causes suction of endothelium after endothelial of cornea- star folds. 6. IOL-opti border touching the centre of endotheliumà IOLhaptic. Scratching if viscomet is not administered and a/c is shallow. Broken capsulotomy bent Needle→if used for air injection rough edge touches the endothelium.

Descemet’s folds Causes 1. Ragged incision by blunt blade→lifts the descemets membrane. 2. Shallow a/c when And during introduction of needle→chance of separation decemets. 3. This leads into Lamellar injection of viscomet. 4. So slanting endothelial incision with sharp blade at 10 to 11o’clock position is better. 5. Immediately aspiration puncture—gush of acquous→inject viscomet to prevent shallow a/c 6. DELAY-makes the a/c shallow→the cycle repeats.

CHAPTER

3

Posterior Capsular Rupture—Rent

65


After having gone through the journals, attending conferences, I understand that some of our Ophthalmic practitioners are facing some problems in ECCE of IOL surgeries. I am writing this article when most of us are striving hard to practice small incision surgeries and phaco and Microphaco. This will be Useful for Beginners. The following are the common complications Iris prolapses, posterior capsular rent and vitreous loss, endothelial damage, endoophthalmitis, zonular dehiscences and etc. In this section, I am making an attempt in relation to the causation of PC rupture and how to prevent the same. I am confining myself only to planned ECCE with routine IOL surgeries excluding small incision surgeries. As we all know, PC rupture is a dreaded complication for the surgeon as his ambition to do a better PC. IOL is simply shattered throwing us in the lurch and to redecide the alternate ways to complete. The following are the circumstances, where in the PC rent or rupture can occur during.

66 Manual of Practical Cataract Surgery I Incision 1. Limbal incision with sharp blade in myopic eyes.

IV During irrigation

II Anterior Capsulotomy

III Hydro Dissection

2. 3. 4. 5. 6. 7. 8.

Illumination 10. Not a bolus and Magnification 11. Multiple small amounts Dialatation in different positions Big needle tip under the anterior capsule Scleral side flap if big. A/c flat Surgeon should have excellent visual control. 9. Repeating the capsulotomy (digging in the same groove) may produce PC tear. V. Delivery of nucleus

VI Implantation

12. A/c should be always full and never flat. 13. Moderate fluid -fast 14.

15.

16. 17.

18. Small scleral side flap 25. Introducing lower haptic of anterior capsulotomy with pressure on the PC sliding delivery. 19. Pressure should not 26. Sharp edge of the optic be at the centre of when the A/c is shallow. cornea. Pupils should be 20. Adequate side of fully dialated opening of anterior (if small dialate capsulotomy. with adrenaline 21. Adequate limbal open or other methods). ing for easy delivery of Speed- the fluid nucleus. speed should not 22. Pupil should be fully directly hit on the dialated. posterior capsule. Aspiration needle 23. Pressure should not should be smoothbe on the zonules. spicule may tear. Aspiration needle 24. It should be on the tip should not equatorial part of pierce the PC or anterior capsule-to plunge.

1. Incision: Making deep limbal incision with sharp blade in a myopic eye, can produce iridodialyses, zonular tear and disturbance to vitreous as the sclera is thinner than normal.


67

Fig. 3.1

2. Ilumination: Should be good enough, to see every step in surgery, what exactly is going on while working inside the globe. Dim illumination ( in the microscope or focusing lamp ) will lead to un-understanding of the procedure in the surgery. 3. Magnification: The surgeon should immmediately change to higher magnification (from 0.6 to 1 or 1.6) and do the anterior capsulotomy with an excellent visual control. It is always better to do anterior capsulotomy under higher magnification. 4. Dialation: Pupil should be fully dialated to see what is happening in each step of surgery. If pupil is small, try to dialate the pupil with adrenaline - BSF Mixture. If undialating pupil as in PX F syndrome, it is better to do keyhole iridectomy and do anterior capsulotomy. Once IOL insertion is over, pigment epithelium of iris may be brought out and sutured with 10.0 suture with closely cut knot left inside. Some prefer to do sphin, cterotomy either at 12 O'clock position only or in two places one at 11 O'clock and 1 O'clock position. 5. Small needle tip: For this a recollection of the brief anatomy of the anterior segment - LENS.


Figs 3.2A and B

Lens is a bispherical sphero base in prism, wherein, apex of the cone is the equator which is rounder, when the accommodation is paralysed the diameter is 9-10 mm (1-2 mm shorter than the diameter of the cornea). Thickness at the centre is 4-5 mm. At the periphery about 1-2 mm. Posterior capsule is 1/5 of thickness than that of anterior capsule. Capsule at the equator is also thicker.

Figs 3.3A to D

Needle Measurement 26 G needle 12 mm long-bevelled edge measures 2 mm, wherein hole is situated there is a tip of 0.5 mm which is flat.

Fig. 3.4


69

Regarding Needle The 26 G needle is used for anterior capsulotomy. We surgeons are bending the needle atleast 1.5-2 mm at the tip for capsulotomy. We always choose to do 5-6 mm diameter of anterior capsulotomy leaving 1.5-2 mm periphery. At the place where we do anterior capsulotomy the thickness of lens may be about 1.5-3 mm, so with big bend of the needle there is every chance that we may injure the posterior capsule and anterior vitreous face.

Figs 3.5A to E

This is more so, when we are dealing with patient with deep A/c's. So why not we make a smallest bend i.e., at the edge which measure ½ mm to ¼ mm at the flat sharp edge and prevent the possible damage to posterior capsule. For this, we need a magnification of the optics. Move the optics, well to the temporal side of the eye, increase the magnification from 0.6 to 1.0 or 1.6 and comfortably bend the needle before the start of the surgery-after all, our purpose is to deal with the anterior capsule only.


Fig. 3.6

Sometimes, when we have doubt about our perfectness in anterior capsulotomy, we try digging in the same groove to ensure perfectness. In out attempt to do this procedure we invariably, are likely to damage the posterior capsule and anterior vitreous face. This procedure can be avoided, provided we have a best visual control of the procedure under magnification during first time anterior capsulotomy. In Morgagnian cataract, where the cortex is fluid in nature the fluid (milky white) cortex excudes out immediately and the capsule is adherent to nucleus and closer to posterior capsule. Here the chances of PC rupture is much more.

Figs 3.7A and B

Scleral side of the Anterior capsulotomy Should be small, so that on pressure at 6 O'clock position, the 12 O'clock portion of nucleus tilts up and gets unsleeved, provided the sclera at 12 O'clock position is adequately pressed,with sustained pressure at 6 O'clock portion of capsule the nucleus is squeezed out.


71

Fig. 3.8

Whereas if the scleral side anterior capsulotomy is big enough, on pressure at 6 O'clock position of capsule, the nucleus has to undergo a big sweep -it becomes vertical. This produces rupture of posterior capsule, disturbance of anterior vitreous face and disturbance. In addition, the thick hard nucleus as in brown cataract produces endothelial damage of the cornea.

Figs 3.9A and B

Shallow Anterior Chamber The anterior chamber should not be allowed to become shallow and flat. Shallow anterior chamber allows the anterior vitreous face and posterior capsule to rise up, along with flat cornea. In such a situation, aspiration sucks the endothelium of cornea or posterior capsule which depends on the situation.

Fig. 3.10

72 Manual of Practical Cataract Surgery Excellent Visual Control With adequate magnification, surgeon should see what happens in each step. Repeating the capsulotomy Some surgeons with a doubt about the perfectness of the capsulotomy, may try digging in the same groove may result in rupture as the thickness in the periphery is small and tapering.

Fig. 3.11

Hydrodissection This is usually done with either BSF fluid or ringer lactate injecting under the anterior capsule with a bolus of one or 2 cc's fastly may result in perforation of the central part of posterior capsule which is 1/5 of the thickness compared to the anterior capsule.

Fig. 3.12

Instead multiple injection in various directions like 3,5,7,9 O'clock position in small quantities can avoid such mishappenings.


73

Figs 3.13A and B

During irrigation and aspiration The purpose of this is to maintain the eye. IOP and shape, and to make the cortex float for easy aspiration. By doing so with BSF fluid or ringer lactate, we are likely to create hole or tear by the following ways. 1. Fast speed of the fluid may hit on the posterior capsules, which is 1/5 th of the thickness of anterior capsules.

Fig. 3.14

2. Tip of the cannula itself can cause tear when you plunge.

Fig. 3.15

74 Manual of Practical Cataract Surgery 3. Irregular surface or small spicule in the under surface of cannula can tear, posterior capsule. To avoid this, ensure that the under surface of the cannula is smooth prior to surgery. While doing irrigation, introduce the cannula parallel to the surface of the iris and slightly tilt down and immediately go under the anterior capsule upto the priphery. Make sure, that the fluid flows straight to hit only the area 1 mm above the equator i.e., at the anterior capsule of the periphery and never at the centre. Engage the cortex, bring to the centre from all around and then aspirate. If you ensure this, the fluid can be allowed to run faster to maintain anterior chamber.

Fig. 3.16A and B

The tip of the cannula should never be allowed to touch the posterior capsule. Make sure that anterior chamber does not become shallow, as it may produce central hole during aspiration. During this procedure, the pupil should be kept well dilated. If the pupil constricts dilate it either with adrenaline BSF mixture or other methods. If the pupil is persistently small as in PX syndrome- a keyhole iridectomy followed by resuturing at the end is mandatory. Irrigation and aspiration in small pupil is not advised. During delivery of Nucleus As described earlier, anatomically, when we press with lens hook at 6 O'clock position of the limbus, we create invariably dehiscence of zonules, as the diameter of the lens is smaller


75

than the corneal diameter by 1-2 mm. This can be seen when we aspirate a broad based tag with cortex.

Fig. 3.17

Instead if we press about 1-2 mm above in the cornea with a slender vectis we are actually pressing at the edge of the capsule which result in squeezing out of the nucleus, provided the pupil is well dialated, adequate capsulotomy, and corneoscleral section to dispel the nucleus.

Fig. 3.18

Using vectis is better than the sturdy lens hook which is often used as cautery in some centers.

Fig. 3.19

In case we press at the middle of the cornea, the nucleus exerts pressure on the posterior capsule and anterior vitreous face which results in PC rupture and vitreous disturbance of drifting forwards.


Fig. 3.20

During Implantation When the anterior chamber is shallow with small pupil, even the introduction of lower haptics blindly with a little force may result in PC rupture Summary for how to prevent Complications in Planned ECCE and IOL

Another methods Corneoscleral Incision


77

Extension of incision

Figs 3.21A to X


Figs 3.22A to L

CHAPTER

4

Capsulorhexis in Detail

79


Capsulorhexis is one of the methods by which the anterior capsulotomy is done to deliver the Lens, wash the cortex, and finally introduce the IOL inside the bag. This ensures a clear cut margin-border of the anterior capsulotomy which appears cosmetically good. Also, during the procedure of aspiration of cortex, the risk of aspiration of tags of anterior capsule without our knowledge is averted. This type of risk is very common during the can opener method of anterior capsulotomy. Here during the aspiration of cortex, the tags of anterior capsule creates a tear extending radially to the posterior capsule which is thinner by five times than the anterior capsule. This creates in disturbance to anterior vitreus face. This, in turn, results in vitreous disturbance along with excentric position of the pupil. This produces an inability to place the IOL in position inside the capsular bag.

Types of Capsulotomy 1. Anterior Capsulotomy. 2. Posterior Capsulotomy.

80 Manual of Practical Cataract Surgery POSTERIOR CAPSULOTOMY This is done in the centre or axial portion of posterior capsule. The usual size of posterior capsulotomy is 4mm. This is carefully done under the microscope with the magnification to create a punched out hole which is smaller than the size of the Optic of IOL. So that it does not disturb the anterior vitreous face. ANTERIOR CAPSULOTOMY This is the primary procedure to create a circular rent at the centre in the axial portion with a clear-cut border to deliver the nucleus comfortably, aspirate the cortex without any complication and to introduce the IOL inside the capsular bag. The usual diameter of the anterior capsulotomy is 5-6 mm. USES OF CAPSULOTOMY

In anterior capsulotomy The tags produced as a result of irregular can-opener method or any other methods is carefully prevented as this method of anterior capsulorhexis -produces a clear-cut border (like a punched out border) and that the chances of creating a tag is not possible. This produces an acceptably (though not cosmetically) good, regular and clear-cut and circular margin in the axial portion of the globe.

In posterior capsulorhexis The chances of formation and creation of posterior capsular opacity (as a result of failed attempt in the formation of new


81

lens fibers) in young patients is carefully prevented, provided an associated anterior vitrectomy is also done. Procedures Capsulorhexis consists of an initial puncture of anterior capsule at the center, in the axial portion, to create a free fold of the capsule followed by a circular tear of the same flap either by utratas forceps or by any other forceps of surgeons choice, and by pulling the freely hanging flap to create a circular rent or by carefull pushing of the same flap from the attached portion of the whole capsule near the junction between the attached portion of the lens capsule and the origin of the free flap, to deliver the nucleus out and to introduce the PC IOL. Here the pushing of the free flap from the junction is done circularly with an axis at the center. For initial puncture, any sharp needle is enough. Once this is done, the tension in the capsule is released, which creates a gap.

Fig. 4.1

This gap creates a useful free flap with a scope to create a linear circular tear with an axis at the center of the anterior capsule starting from the lower arm. This is achieved when the initial puncture is a slanting C, in which the lower arm is directed to create an anticlockwise circular tear either by a pull of the free flap or a push of the same from the original anterior capsule.

82 Manual of Practical Cataract Surgery If the initial puncture is a reverse slanting C, the lower arm of C is directed to create a clockwise movement of the free flap (by a forceps or a bent needle ) with an axis at the center. The purpose is to make a circular rent with a diameter of 5 mm, upto 6mm. The lower half of free arm of C should be directed in such a way to create a circular tear or rent. The size of the rhexis can also be 4mm in diameter. This is usefull in the posterior capsule which is thinner by 5 times than that of anterior capsule. This is useful to introduce the optic portion of the IOL behind the posterior capsule when the haptic portion is left inside. The capsular bag and vice-versa, to avoid the subsequent development of posterior capsular proliferation of new lens fibers leaving an opacity (posterior capsular opacity) especially in children and young people. Just try to raise the flap, fold it, and from the base of the flap one can, with the tip of a cystitome, push the free flap circularly with the axis at the center or pull the flap circularly with the tip of the needle. Usually most of the surgeons use a 90 degree bent needle to push or pull. But when using a 90 degree bent needle, it usually punctures the free flap and jeopardizes the further procedures, creating tension to the surgeon during surgery. The surgeons can do this rhexis by pulling the free anterior capsular flap. In a circular fashion to create a circular clear-cut rent with the tip of a cystitome just below the junction. The symbol C, is to direct the line of tear in the free flap of anterior capsule to go circularly in an anti clockwise pattern on the right side. Otherwise our attempt to create a circular tear gets spoiled. Figures 4.2 and 4.3.


83

Anterior capsulorhexis Starting from right side movement

⎯⎯→

Anticlockwise magnified magnified

Push the flap as indicated above at the junction of free and attached portion of anterior capsule with the tip of the needle Figs 4.2A to H

84 Manual of Practical Cataract Surgery Anterior capsulorhexis Starting from right side movement

⎯⎯→ —

Anticlockwise Magnified

Gently pull the free flap as indicated with the tip of needle Figs 4.3A to H

REVERSE C The anterior capsulotomy can also be made using a reverse C in which the lower arm of the reverse C is directed upto create a free flap. Here the free flap can be directed to tear as circular rent in a clockwise pattern with an axis at the center. Figure 4.4 and 4.5. REPEAT CAPSULORHEXIS In case the rhexis is not successful, small, irregular and not satisfactory, a repeat capsulorhexis can be done around the


85

Anterior capsulorhexis — Starting from left side — Clockwise movement (roation of flap) — Reverse — C method magnified

Push the free flap at the junction with the tip of the needle at the periphery Figs 4.4A to H

86 Manual of Practical Cataract Surgery Anterior Capsulorhexis — Starting from left side — Clockwise roation of flap) — Reverse ‘C’ = ‘C’ method magnified

Gently Pull the free flap all around with the tip of the needle at the periphery Figs 4.5A to H


87

failed 5 mm rhexis making it into a 6–7 mm rhexis. For this the lower arm of regular C or reverse C or U-shaped incision can be done around the failed one. This is useful in anterior capsulotomy only as the size is bigger. In Regular type The lower arm of C or U-shaped flap can be raised with the help of a cystitome outside the failed flap at 9 O’clock position the flap can be raised and pushed at an anticlockwise pattern circularly to create a clear cut border. Or the lower arm of C or U-shaped nick can be made outside the failed one at 3 O’clock position, raise the flap with the cystitome and pull or push as per the necessity, to create a circular rent or capsulotomy. Figures 4.6 and 4.7. METHOD- 2 Some surgeons prefer to peal the border circularly outside the original capsulotomy to make it into a 6-7mm capsulotomy with a clear - cut border. The beginner can learn and practice this on a red tomato. METHOD-3 To admit the IOL inside the capsular bag, in case the diameter of capsule-rhexis is small, one can make 2 radial cuts from the clear-cut border of the rhexis - one at 10 O’clock position, another at 2 O’clock position. Instead, the surgeon can do this at 5 O’clock and 8 O’clock position of the border. PURPOSE OF MAKING IT BIGGER The purpose of making the rhexis bigger is to admit the IOL easily inside. The capsular bag and to deliver the nucleus easily from inside the capsular bag.

88 Manual of Practical Cataract Surgery Anterior Capsulorhexis from right side anticlockwise rotation of flap – Magnified For small irregular

Make a small side incision raise the flap → pull the free flap all around from the existing Figs 4.6A to I

PURPOSE OF CAPSULORHEXIS In case of can - opener method, the inner border of the rhexis is irregular with the tags projecting. The tags, during the aspiration of cortex, by a cannula mounted on a syringe


89

Repeat capsulorhex is from left side — Clockwise Rotation Flap magnified

Make a small side incision raise the flap → pull the free flap all around from the existing Figs 4.7A to I

gets extended sometimes creating a tear at posterior capsule producing vitreous disturbance and nucleus or IOL drop. Creation of Cystitome The routine practice of bending the needle (26 gauge) to 45 to 60 degree can be followed and done as usual.

90 Manual of Practical Cataract Surgery Tip of the needle is bent at 90 degree either at the hub of the beveled edge or at the base. The 90 degree bent - tip of the needle, if used to fold the flap and to push the anterior capsular flap to create a circular capsulorhexis with a clear-cut margin, it usually creates a puncture of the flap and tears jeopardizing the procedure. Instead, if the tip is bent for 45 to 60 degrees and used carefully, to push or pull the flap, with the help of the slope in the tip, puncturing and tearing can very well be prevented. COMPLICATIONS The beginners while doing capsulorhexis, they fail to achieve the satisfactory size, of the hole and the shape.. Sometimes it becomes irregular. In order to rectify this unfortunate attempt, the surgeon can re-create a circular rhexis, starting from the edge of it at 3 or 9 O’clock positions or at any suitable position of surgeons choice. and convenience, by creating a free flap from the edge of failed rhexis by doing a U shaped or lower half of C and develop a circular rhexis as suggested in the picture. This can also be done with the same needle or utrtas forceps.

For a capsulorhexis using a forceps ( for beginners) Catch hold of the free flap (after an initial puncture) of anterior capsule at or near the peripheral edge with the forceps of surgeons choice and tear carefully round, millimeter by millimeter carefully, till you complete a circular tear. The same principle is applicable to other methods also (Follow the legends already available).

CHAPTER Understanding the Basics of Strabismus 91

5

Understanding the Basics of Strabismus

PREFACE TO STRABISMUS As everybody is interested in learning phaco and microphaco, and the concentration is diverted towards that line, only a little interest is shown to squint or strabismus Infact, in some centres, the subject is totally eliminated. Hence, I have made an attempt to simplify the subject and express the importance so that everybody can easily understand the subject. It is not my intention to deal elaborately about the details of each and every part of this subject as it is an annexe part of the origional manual phaco. For further detailed knowledge about this subject, the readers are requested to refer appropriate text books and other referances to update their knowledge. The Author

92 Manual of Practical Cataract Surgery Squint or Strabismus Causes of Eso deviation 1. Increased accommodationas in bilateral hypermetropia (superable). 2. Increased convergence as in bilateral congenital myopia.

Exo deviation 1. Decreased accommodation due to bilateral aquired myopia

2. Decreased convergence as in recession of near point in presbyopia. 3. Superable hypermetropia which 3. decreased accommodation in sees at all distances whatever the one eye -decreased convergence refraction of the other eye, (super(as in myopia-hypermetropic able hypermetropia that anisometropia). can be overcome by sustainable accommodation in order to give clear vision).

ANATOMICAL FACTORS Abnormal or relative due to abnormal bony defects. – Congenital – Acquired – Low IPD – High IPD – Trauma – Trauma – Displacement of visual axis – Displacement of visual axis. – Due to lesion in nerve supply – Same to muscles PHYSIOLOGICAL FACTORS – Excessive application of close works

– Esophoria

Dissociation Factors; a) Prolonged uniocular actvity as in watch makers, repairers. Microscopists accompanied by neglect or suppression.


6. Organic nervous or muscles palsies Cerebral tumours Cerebrovascular diseases Neurosyphillis Disseminated sclerosis Myasthenia gravis 6th nerve Palsies 4th nerve palsies

93

– Disease as an early sign – Palsies

7. Precipitation factors Bodily ill-health Ocular fatique Mental illhealth, Advancing age Certain occupations-specific

– Prolonged

Age Factors Eye blind from birth or blinded within first few weeks of life an eye which becomes blind between infancy and adolescence-

– Eye becomes blind from adolescenceDIVERGENCE – CONVERGES On reading the above classification, the reader or the student will understand that there is definitely a relationship between refractive error, accommodation, and convergence. Basic • Eso means deviation of the eye towards the nose. • Exo means deviation of the eye towards the earlobe.

94 Manual of Practical Cataract Surgery • Phorias means a tendency of the eye to deviate. • Tropias means already deviated, developed, established, manifested. Deviation Hypermetropia Hypermetropic astigmatism

if untreated->sustained contraction of ciliary muscles (changes the lens curvature) (Accommodation) Convergence.

= refractive errors(hypermetropia) → accommodation → convergence. One dioptre of hypermetropia produces one diopter of accommodation which in turn produces two meter angles of convergence. The refractive error namely hypermetropia (if uncorrected) produces sustained contraction of ciliary muscles (accommodation) which is also always associated with a determined amount of convergence. This is due to a simultaneous stimulation of the the visual cortex whenever the accommodation reflex is stimulated i.e., accommodative stimulus acts as a trigger mechanism->stimulates->convergence. ACCOMMODATION Is a process by which the lens changes its focus from distance to near and vice- versa. The ciliary muscles through its zonules are attached to the equator of the lens. There are three types of muscles viz., circular, longitudinal and meridional (oblique) muscles. The rays or objects from infinite are parallel rays when accommodation is at rest, falls on the light sensitive layers


95

of the retina after converging by the lens. When the object comes closer and closer, the rays becomes divergent. And so they fall behind the light sensitive layers of retina. One diopter of hypermetropia creates one diopter of accommodation, which in turn creates two meter angles of convergence--one meter angle for each eye. Although the incident-infinite distant rays(objects) are parallel, the emergent rays from the eyes should have a wider field in each eye having an overlaping of the two fields producing binocular single vision. This binocular single vision consists of three processes viz. 1. Simultaneous perception. 2. Fusion. 3. Stereopsis (depth perception) For this, both eyes should have an acceptably good vision, having a simultaneous perception,to fuse the two objects having stereopsis (depth perception). The process of accommodation varies as the child grows old. At the age of 10 yrs the accommodation is at 7 inches, which recedes to 22 inches at the age of 40, and recedes more and more as the age advances. In case the individual is hypermetropic, even for distance (infinite), the ciliary muscles are in a state of sustained contraction, producing pain, headache, and eye-strain. If circular muscles are acting, there will be pain around the eye. When radial or longitudinal muscles are acting, the pain will be radiating to the back of the head. Possibly there may be a relationship of oblique muscles to that of astigmatism. This is an unauthorised deduction. There is an associated convergence in relation to the accommodation. Accommodation and convergence are both reflex processes which has the control at the area no. 17 to 19.of visual cortex.

96 Manual of Practical Cataract Surgery Nerve Pathways Accommodation and convergence have different nerve pathways. This is also important to know where the level of lesion is. The accommodation may fail, paralyse, or may become insufficient in certain conditions and similarly spasm of accommodation may also occur. Cycloplegia or Paralysis of Accommodation The following are the conditions where it occurs: a. Cycloplegic drugs -may be unilateral or bilateral. b. 3rd nerve paralysis or paresis. c. Alcoholism, diabetes, neurological disorders. d. Sexually transmitted diseases e. Diphtheria, syphillis etc. f. Myopia - defect is not noticed. g. Hypermetropia -both distance and near vision are affected. h. Emmetropia-only near vision alone is affected. Insufficiency of accommodation is seen in presbyopia due to normal physiologically related conditions, ageing, glaucoma, eye strain, due to excessive near work. Spasm of accommodation may occur due to use of miotic drugs. Uncorrected refractive errors, insufficient illumination, anxiety, and tension. Use of drugs-atropine, can abolish the spasm of accommodation and pain also. HETEROPHORIA Phorias may be eso, exo, hyper, hypo, and cyclo. The causes of—

Understanding the Basics of Strabismus Esophoria

97

Exophoria

Purely anatomical anomoly(motor obstacle)which is insufficient to cause manifest deviation. 1. Orbital asymmetry. Orbital asymmetry 2. Abnormality in IPD (Narrow) Wide IPD. 3. Slight degree of ocular muscle Medial rectus palsy. paresis. Early degree of 6th nerve palsy (Lateral rectus palsy).

ACCOMMODATION AND CONVERGENCE FACTORS Demand for increased accommDemand for decreased accommodation as in superable odation as in acquired myopia hypermetropia. decreased convergence as in (OR) presbyopia. Demand for increased convergence as in congenital myopia. Excessive use of eyes for close works Bodily ill-health or mental ill-health Ocular or general fatique, advancing age. Certain occupations which require prolonged ocular activity and mental concentrations.

TYPES There are four types: 1. Convergence excess type: Maddox wing reading is larger than obtained in maddox rod. 2. Divergence weakness type: Maddox Rod reading is larger than seen in wing

1.

2.

Convergence weakness type: Maddox wing reading is larger than obtained in maddox rod. Divergence excess type: Maddox rod reading is larger than obtained in maddox wing.

98 Manual of Practical Cataract Surgery SYMPTOMS Depends on decompensation. Sometimes larger phorias may not produce symptoms. But smaller phorias can cause severe symptoms. People who do more close works may produce more symptoms than others like farmers.

Symptoms in uncompensated phorias patients may produce: 1. Symptoms of muscles fatigue like headache or aching pains, which disappears on closing one eye. 2. Difficulty in changing focus- near to distance and vice versa. 3. Photophobia- which disappears using dark glasses or relieved by closing one eye.

Symptoms due to difficulty to maintain binocular vision: 1. Blurring of letters. 2. Intermittant diplopia (due to temporary deviation of visual axis). 3. Intermittant squint which is noticed by friends.

Symptoms due to defective postural sensations: • Transmitted from ocular muscles due to alteration of muscles. • Tones-like landing of aircrafts or during playing games. Eye Examinations 1. Vision(both distance and near vision) in both eyes. 2. Cycloplegic refraction and correction with spectacles. Hypermetropia must be fully corrected as this is closely


99

related to accommodation and convergence, though myopia may be undercorrected. As the spasm of accommodation is the cause for headache, (even for distance ) Hypermetropia has to be fully corrected. 3. Ocular movements in nine cardinal positions should be done. Diplopia chart testing is a useful examination. 4. To find out the angle of deviation a. Corneal reflex testing (hirschberg test) in infants.

Fig. 5.1

Cover Test Is to find out "recovery movement" to resume binocular fixation. There are three tests in this: • Cover test for -Tropias. • Cover and uncover test -for phorias. • Alternate cover test - for phorias and tropias. • Prism bar cover test - to quantitatively measure the total deviation. • Prisms are placed with the apex pointng towards deviation. • When prisms are being changed, always make sure that the other eye is covered. • Base-in or out prism - placed appropriately in front of one eye and then perform alternate cover test, until there is no refixation movement.

100 Manual of Practical Cataract Surgery 6. Measurement of ange of deviation. • Perimetry method. • By Synaptophore method and measure the angle of deviation. • By Maddox rod and maddox wing test. • With the help of maddox rod at a distance of 6 meters in one eye and look for the streek of light producing crossed diplopia (right side streek crossing to the left side.Exophoria) or uncrossed diplopia -Esophoria. The amount of separation can be measured by a prismbar to find out the amount of angle of deviation. The Maddox wing test is for near (33 cm). 7. Measurement of accommodation by RAF ruler. 8. Measurement of convergence by RAF ruler. 9. Diplopia tests. 10. Worths Four-dot tests. 11. State of binocular vision-an assesment to be done.


Figs 5.2A to E (For color version see Plate 1)

101


Figs 5.3A to C (For color version see Plate 2)



103





105

106 Manual of Practical Cataract Surgery Maddox Rod tests one fullpage • Ask the patient to see a pen torch light. • Maddox Rod to be placed in one eye, other eye — normal.

→ Esophoria • Correct with base out prism.

→ No horizontal phoria.

→ Exophoria • Correct with base in prism.

Figs 5.7A to D


107

TREATMENT OF PHORIAS a. Refractive errors are to be corrected. Hypermetropia even for distance should be fully corrected to relieve the sustained contraction of ciliary muscles (accommodation), astgmatism and myopia also should be corrected. b. Orthoptic treatment --This is mainly useful in convergence insufficiency and also in exophorias by doing fusional exercises.to improove fusional reserve. c. Prismatic spectacles - this is only a temporary arrangement in elderly patients and not a cure in this condition. d. Improvement of general health. This is an important measure as most of the patients suffer due to serious diseases of physical and mental conditions. e. Surgery if necessary and in selective cases. Flow Chart

• The Macular fixation develops in 2 to 3months after birth. • Convergence and accommodation reflexes develop 2 to 3 months after birth. These reflex center is situated in the occipital cortex areas No. 17 to 19. We have already dealt with heterophorias

108 Manual of Practical Cataract Surgery HETEROTROPIAS The types of tropias are: a. Intermittant-here the deviation is not continuously present. b. Uniocular- in one eye only. c. Alternating- in this the vision in each eye is almost the same. But at a time, only one eye is fixing while the other is deviating and vice versa. d. Constant- here the deviation is always present. e. Infantile esotropia. f. Accommodative esotropia. g. Non-accommodative and partially accommodative. Qualitative Types Esotropia, exotropia, hypertropia, hypotropia etc. The causes of esotropias and exotropias are;Convergent Squint-(Concomitant)–Esotropia 1. High hypermetropia producing the over action of accommodation (ciliary muscles) as result of synergic action of accommodation and convergence leads to over action of convergence initially and then for distance. 2. Abnormal physiological incooperation of accommodation and convergence. In case of high hypermetropia in children of 2-3 years,if uncorrected may produce Intermittant squint which becomes constant subsequently. 3. Congenital myopia: The new -born child with congenital myopia does not have a stimulus to see distant object but fixes only the near object- the mother. Because the medial rectus is more powerful, it remains convergent


109

4. Congenital Paresis: Due to some unknown reasons, there may be some paralysis or paresis of one or two ocular muscles of eye producing squint. As the macular fixation develops 2-3 months after birth, it is either noticed or not. The same paresis or palsy may also occur as a result of serious illness to the child at this age. The palsy may be in horizontal, vertical or oblique muscles. 5. Dissociation of the eye as a result of uncorrected refractive errors producing hazy unacceptable vision- even if corrected. The corrected power may be under or insufficient. Sometime the astigmatic correction could be incorrect. Extended patching of one eye. Due to congenital aquired macular defect leading to defective fixation. 6. If visual pathways are defective due to some lesion. 7. General ill-health conditions. Divergent Squint: (concomitant) Exotropia 1. Due to Neuro-muscular inco-ordination of unknown reasons at the age of 3 - 5 years divergent squint occurs as intermittant first, ending as constant in the following types: a. Divergent excess types -for distance. b. Convergence insufficiency type for near (maddox wing) 2. Unilateral myopia-uncorrected, producing divergent squint of the myopic eye. In bilateral myopia, if untreated - produce alternating type of divergent squint. 3. As a result of some serious pathology in the eye producing loss of eye presents as divergent squint. 4. Overcorrection in convergent squint. 5. Medial rectus paralysis in 3rd nerve palsy. 6. General ill-health, etc.

110 Manual of Practical Cataract Surgery Points to remember in Esotropia a. High hypermetropia ->overaction of ciliary muscles-> overaction of convergence for near first->Squint. b. Uncorrected high hypermetropia (due to inco-ordination between accommodation and convergence)->deviation intermittant first, below 3 years. c. Myopia from birth->in infants -> esotropia persists. d. in infants ->paralysis or paresis ->tropia of all types. e. uncorrected and under corrected refractive errors -> unequal vision and clarity. f. Macular pathology in infancy-or anywhere in visual pathology. g. Defective general health. Points to remember in Exotropia a. Neuromuscular inco-ordination->after 3 years >intermittant->constant-primary-not appear to be related to refractive errors. b. Unilateral myopia or myopic astigmatism -> one eye>divergent. c. Bilateral myopia-> alternating squint. d. Eye with no vision->Exotropia. Symptoms 1. In early cases there will be diplopia, subsequently followed by absence of diplopia ->supression. 2. Cosmetically defective appearance.-deviation of one or both eyes as noticd by parents or relatives. 3. In school children it is noticed. 4. In children, if is noticed along with yellow or white reflex of pupils (one should exclude the various causes of pseudoglioma mainly retinoblastoma in children).


111

Eye Examination--routine 1. Inspection: • To find out whether convergent or divergent squint. • To find out small degree, moderate or severe degree pseudosquint or true squint. • Sudden onset or gradual onset. • Intermittant or constant type (an observer can notice) family history. 2. Vision- aquity. 3. Ocular motility: • To find out whether it is a paralytic or non-paralytic each eye should be tested separately. 4. Pupillary reflexes: • To rule out the other causes of peudoglioma especially retinoblastoma. 5. Cycloplegic refraction to find out the refractive errors. 6. Cover test -in children, using a torch light one can find out approximatively the angle of deviation in degrees. • Cover one eye and look for recovery movements. Though this tests is not much useful in obvious squint, it is an important test to find out whether the child is fixing uniocularly or bilaterally. The co-operation of the child is difficult. 7. To find out the angle of deviation: a. Corneal reflex test -useful in children as mentioned. b. Perimeter test -The number of degrees on the arc will give a clue to the angle of deviation. c. Prism and cover test – By changing the increasing strength of prisms (base-in or base out for convergent or divergent squint) till the recovery movement is abolished one can find out the correct amount of deviation.

112 Manual of Practical Cataract Surgery d. Maddox wing and maddox rod test. This test is not usefull but may be usefull in some cases. Bagolinis striated lens test interpretation

Figs 5.8A to D


113

8. Binocular Function test: a. Simultaneus perception test: In synaptophore, by using slides of two dissimilar objects the patient may be asked to see slides like -lion and cage and asking them to put the lion in the cage. b. Fusion: In this, there will be two slides of dissimilar pictures but incomplete, like cat or rabbit holding flowers. By asking the patients to fuse both into one complete picture (super-imposed) the patient has the ability to fuse. In case it does not, but simply comes and goes -it may be taken as suppresion. c. Stereopsis(depth perception): In this, there are slides of two dissimilar objects. The patient is asked to appreciate the depth by superimposeing both. TREATMENT This consists of the following: a. Correction of refractive errors by spectacles. b. In case the patient has developed amblyopia occlusion of the fixing eye should be done, followed by stimulation of the affected-amblyopic eye. If exccentric fixation has developed, the occlusion of the affected eye should be done. To make the unsteady fixation into steady fixation.Then follow the previous procedure. c. Orthoptic procedures, if necessary to create binocular vision. d. Surgery as a cosmatic correction in some patients. CONVERGENCE Convergence is a process by which the visual axis of both the eyes are directed towards the nose by synchronous adduction of both the medial recti muscles.

114 Manual of Practical Cataract Surgery Types of Convergence: Convergence may be voluntary or reflexes. It is initiated in the visual cortex. The reflex convergence is analysed in 4 components: 1. Tonic convergence. 2. Accommodative convergence. 3. Fusional convergence. 4. Proximal convergence. Tonic Convergence This depends on the tone of the muscles and occurs in the absence of any stimulation to accommodation. In cases of convergence-excess type, a non-accommodative esotropia is seen. Treatment By drugs Accommodative Convergence Normally when accommodation is exerted, an estimated amount of convergence is also exerted. Treatment This can be corrected by correcting refractive errors. Fusional Convergence Normally a certain amount of convergence is present for a normal accommodation. For finer adjustments necessary for binocular fixation -> this fusional convergence is required. This is involuntary. Proximal Convergence: An awareness of near object or subject creates an appropriate degree of convergence.

Understanding the Basics of Strabismus Flow Chart: Treatment of concomitant squint in a child

115

116 Manual of Practical Cataract Surgery Flow Chart: Treatment of concomitant squint in an adult


117

Amblyopia Amblyopia can be discussed in the following types: 1. Stimulus deprivation amblyopia. 2. Strabismic amblyopia. 3. Anisometropic amblyopia. 4. Anisoconic amblyopia. 5. Ametropic amblyopia.

Treatment 1. Treatment of the cause of amblyopia. 2. Patching or occlusion of the normal eye so that the affected eye can be made to see and be stimulated by some methods. Eccentric Fixation The following are the types: 1. Fovial fixation. 2. Perifovial fixation. 3. Parafovial fixation.

Treatment 1. Occlusion or Patching of the affected eye so that the normal eye which is unsteady can be made to become steady. 2. Once the eye becomes steady, the regular treatment for amblyopia can be started. which is given above. PARALYTIC SQUINT Causes of paralysis of external ocular muscles 1. Any type of lesion in any one of the muscles or the nerve which supplies the same muscle starting from the nucleus of origin upto the place of insertion in the eye,

118 Manual of Practical Cataract Surgery like congenital anomolies, infection, inflammation, benign or malignant conditions, trauma, toxins, vascular or spaceoccupying conditions can paralyse the function of the muscles producing the deviation of the eye-paralytic squint. a. Superior rectus, inferior rectus. b. Medial rectus, lateral rectus. c. Superior oblique, inferior oblique muscles. Lateral rectus muscle is supplied by 6th nerve (abducent nerve). Superior oblique muscle is supplied by 4th nerve (trochlear nerve) superior rectus, inferior rectus, medial rectus and inferior oblique --3rd nerve. 2. Sequelae of the affected muscles will be a. Overaction of the contralateral synergist. b. Contracture of the ipsilateral antagonist. c. Secondary palsy of the contralateral antagonist. The examples are: a. For right lateral rectus palsy-the sequela are -overaction of left medial rectus, contracture of right medial rectus and secondary palsy of left lateral rectus. b. For left superior oblique palsy-sequela are -overaction of right inferior rectus, contracure of the left inferior oblique and secondary palsy of right superior rectus. 3. Clinically the signs and symptoms are: a. Diplopia(immediate) if the eye is having vision. b. Due to this diplopia, the patient will have headache, nausea, vertigo, and other discomforts which gets cleared on closing the affected eye. c. Defective movement of the affected eye. d. Compensatory head posture and chin position. Investigations a. Diplopia chart to find out which specific side muscle is affected.


119

b. Clinical demonstration of restriction of movement of the particular muscle. Each affected muscle has different diplopia charting, compensatory headposture and chin position to avoid the discomforts of the diplopia. Treatment 1. Treatment of the cause, if possible and curable. 2. Occlusion of the affected eye by some means to eliminate the discomfort for diplopia. 3. Temporary prismatic spectacles if available. 4. Appropriate surgical procedures to tackle the problem towards the improvement of the situation as it is difficult in most of the conditions.

120 Manual of Practical Cataract Surgery Diagnostic features of palsy of extrinsic muscles Muscle and nerve supply

Ocular posture

Defective movement

Diplopia Type

Greatest separation of images

Usual comp -ensatory head postures

Lateral Rectus

Eye turned in

Outwards (abduction)

horizontal homonymous

on abduction

Face turned towards affected side side(also chin may be lowered)

Eye turned out

Inwards (adduction)

Horizontal crossed

On adduction

Face turne towards normal side (also chin may be raised

Eye turned downwards (and slightly outwards)

Upwards when the eye is abducted

Vertical, upper On elevation (false) image outwards belonging to affected eye; also intorsional and corssed

Chin raised and head usually turned and tilted towards affected side

Eye turned Downwards upwards when the (and slightly eye is abducoutwards) ted

Vertocal, upper On de(False) image pression belonging to outwards affected eye;

Chin lowered and face usually turned towards affected side and head tilted towards the normal side

Eye Downwards turned up- when the eye wards (and is adducted slightly inwards)

vertical, lower On depress(false) image ion outwbelonging to ards affected eye; also intorsional crossed

Chin lowered and head tilted ad turned towards normal side

Eye turned Upwards downwards when the (and slightly eye is inwards) adducted

Vertical, upper On (false) image elevation belonging to inwards affected eye; also extorsional and crossed

Chin raised and face turned towards normal side and head tilted towards affected side

Sixth Cerebral Medial Rectus Third Cerebral Superior rectus Third cerebral Inferior Rectus Third cerebral

Superior oblique Fourth cerebral Inferior Oblique

Index A Accommodation 94 cycloplegia 96 nerve pathways 96 paralysis 96 Accommodation and convergence factors 97 Amblyopia 117 treatment 117

B Bagolinis striated lens test interpretation 112 Basics of strabismus 91 anatomical factors 92 physiological factors 92 Bridle suture 3

Complications in planned ECCE 46 Concomitant squint 115 Conjunctival incision 4 Conjunctival closure 32 Convergence 113 accommodative 114 treatment 114 fusional 114 proximal 114 tonic 114 treatment 114 Cover test 99

D Delivery of nucleus 74 Descemet ’s detachment in SICS 37

C

E

Capsulorhexis 12, 79 complications 90 purpose 79 Capsulotomy 79 procedures 81 types 79 anterior 80 posterior 80 uses 80 in anterior capsulotomy 80 in posterior capsulorhexis 80

Eccentric fixation 117 treatment 117 Epinucleus delivery 30 Esophoria 97 Excellent visual control 72 Exophoria 97 Extention of incision 16

F Frown incision 5

H Half nucleus delivery 35 Heterophoria 96

122 Manual of Practical Cataract Surgery Heterotropias 108 qualitative types 108 convergent squint 108 divergent squint 109 High magnification 51 Hydrodissection 16, 72 Hypermetropia 99

I Implantation 76 Insertion of IOL 31 Iridodialysis 33 Irrigating vectis method 25 Irrigation and aspiration 73

L Linear incision 5 Low magnification 48

M Maddox rod test 112 Maddox wing 112 Manual phaco 1 complications 1 prevention 1 Manual rotation of nucleus 17 McPherson forceps 58 Morgagnian cataract 70

Paralytic squint 117 causes 117 investigations 118 treatment 119 Posterior capsular rupture 65 dialation 67 illumination 67 incision 66 magnification 67 small needle tip 67

R Repeat capsulorhexis 84

S Scleral incision 5 Scleral side of anterior capsulotomy 70 Shallow anterior chamber 71 Side port incision 9 Small pupil 21 Small rhexis 21 Small scleral side capsulotomy 48 Smiling face technique 60 Superior rectus fixation 3

T Treatment of phorias 107 Tunnel making 6

N

U

Nucleus 18, 22, 34, 43 delivery 18, 22 rotation 43 sinking 34

Undialated pupil 21 Utratas forceps 90 Uveitis 21

P

Vectis method 25

Palsy of extrinsic muscles 120 diagnostic features 120

W

V

Worth’s four dot test 100

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