Ординатура / Офтальмология / Английские материалы / Manual of Practical Cataract Surgery_Sundararajan_2009
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Contents
1. |
How to Prevent Complications in |
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Manual Phaco? ............................................................ |
1 |
2. |
How to Prevent Complications in Planned |
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ECCE and PCIOL? .................................................... |
45 |
3. |
Posterior Capsular Rupture—Rent ........................ |
65 |
4. |
Capsulorhexis in Detail ........................................... |
79 |
5. |
Understanding the Basics of Strabismus ............. |
91 |
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Index ........................................................................... |
121 |
How to Prevent Complications in Manual Phaco? 1 CHAPTER 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.
How to Prevent Complications in Manual Phaco? 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
How to Prevent Complications in Manual Phaco? 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.
How to Prevent Complications in Manual Phaco? 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.