Ординатура / Офтальмология / Английские материалы / Manual of Practical Cataract Surgery_Sundararajan_2009
.pdf
Posterior Capsular Rupture—Rent 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.
70 Manual of Practical Cataract Surgery
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.
Posterior Capsular Rupture—Rent 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.
Posterior Capsular Rupture—Rent 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
Posterior Capsular Rupture—Rent 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.
76 Manual of Practical Cataract Surgery
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
Posterior Capsular Rupture—Rent 77
Extension of incision
Figs 3.21A to X
78 Manual of Practical Cataract Surgery
Figs 3.22A to L