Eyeworld

EW NEWS & OPINION 14 Dr. Devgan, Devgan Eye Surgery, Los Angeles, and Beverly Hills, Calif., details his approach to cataract surgery for patients with posterior polar cataracts P osterior polar cataracts are congenital opacities at the posterior pole of the crys- talline lens. Multiple fac- tors may play a role in their formation, with recent evi- dence pointing to a recurrent muta- tion in the PITX3 gene. 1 The posterior polar opacities can be asso- ciated with other ocular develop- mental defects, particularly of the iris or other structures of the ante- rior segment. These types of poste- rior lens opacities can progress over the years and become more visually significant, leading to a decline in visual acuity and necessitating cataract surgery. Phacoemulsification of a poste- rior polar cataract is particularly challenging because the posterior capsule can be weak, fragile, or even absent at the site of the opacity. This leads to a higher risk of posterior capsule rupture, vitreous loss, and other complications. Initial studies have demonstrated that this risk is as high as 26% 2 to 36% 3 although re- cent reports peg the risk a bit lower at 11%. 4 The size of the posterior polar opacity may also influence the risk of capsular rupture, with larger opacities thought to have a higher risk. 5 Multiple surgical techniques and approaches have been de- scribed, but the one common goal is to avoid manipulation of the poste- rior capsule at the site of the poste- rior polar opacity. The technique that I prefer is hydrodelineation to remove the central lens endonu- cleus, followed by viscodissection of the remaining lens epinucleus and cortex. 6,7 The surgical technique Creation of a well-centered, 5-mm, round capsulorhexis is particularly important in an eye with a posterior polar cataract since there is a signifi- cant chance that the IOL will need to be placed in the ciliary sulcus with optic capture through the ante- rior capsular opening. It is important to avoid perform- ing hydrodissection near the poste- rior lens opacity, since the fluid wave can cause the posterior capsule to rupture and the nucleus to fall into the vitreous. While some sur- geons advocate a small amount of hydrodissection, stopping just shy of the posterior pole, my advice is to avoid this step altogether. Hydrodelineation using a small quantity of balanced salt solution in a syringe with a 27-gauge cannula can be performed since this will sep- arate the endonucleus from the re- maining epinucleus and cortex. The endonucleus can then be removed from the eye using the phaco probe. At this point, all that remains in the capsular bag is the softer lens epinucleus and the cortex. Using a dispersive viscoelastic, which has a more liquid and syrup-like texture than the cohesive viscoelastics, the remaining lens material can be care- fully dissected from the capsule. Using a viscodissection technique in all quadrants of the lens allows for a complete cleaving of all residual lens material from the capsule. This method has several benefits: the vis- coelastic is slow and controlled, it pressurizes the anterior segment, it can tamponade any existing break in the capsule, and it creates a bar- rier between the lens material, which is brought forward, and the capsule and vitreous, which are pushed backward. The irrigation/aspiration probe can be placed in the eye and kept centrally in the anterior segment while the lens material is aspirated. The risk of a capsular rupture is highest during attempted manipula- tion or cleaning of the posterior polar opacity. While the posterior polar opacity can often be removed from the capsular surface, care should be taken to avoid polishing or cleaning. It is far easier and less risky to perform a YAG laser capsulo- tomy to clear the visual axis in the post-op period. Inserting the IOL When the lens material has been re- moved, it is critical not to let the an- terior chamber collapse. This means keeping the I/A probe in the eye in foot pedal position 1 to maintain the infusion pressure and then using the non-dominant hand to inject viscoelastic via the paracentesis inci- sion to fully inflate the capsular bag. At this point the I/A probe can be re- moved from the eye and the new IOL inserted. A three-piece IOL is preferred since it offers more options for placement. The entire IOL can be placed in the capsular bag if the pos- terior capsule is intact. If a defect of the posterior capsule develops dur- ing IOL insertion, the haptics can be August 2011 by Uday Devgan, M.D., F.A.C.S., F.R.C.S. Obtaining successful surgical outcomes for patients with posterior polar cataracts This patient has a posterior polar cataract with a congenital iris defect and absence of zonules in one quadrant Source: Uday Devgan, M.D., F.A.C.S., F.R.C.S. continued on page 17 rePlay online content Former ASCRS cataract clinical commit- tee member Kevin M. Miller, M.D., is one of the top anterior segment sur- geons in California. At UCLA, Kevin has a busy referral practice for complicated cataract cases and he is also directly involved in training residents. (You'll have to ask him which of these two oc- cupational challenges is more stressful.) EyeWorld has asked Kevin to organize a regular series of articles on the man- agement of complicated cataract pa- tients, written by experts of his choosing. This series will follow the out- line of Kevin's AAO instruction course on the same topic, which features many of these same experts on the faculty. I hope that you will find this series worth clipping and saving for when the need next arises. David F. Chang, M.D. chief medical editor D o you ever long for the days when cataract surgery was eas- ier? I do! Either failing memory is keeping me from reliving the actual stress of my early cases, or they are get- ting harder. I hope it's the latter! Where did all the easy cases go? Nowadays, it seems that every eye has something wrong with it other than cataract, some- thing that makes it challenging—prior trauma, Fuchs' dystrophy, pseudoexfolia- tion syndrome, alpha 1 receptor antago- nist usage, a deep orbit, macular degeneration, and the list goes on! A highly varied case mix is becoming the new norm for cataract surgeons. In this new EyeWorld column, well-known speakers will discuss ocular comorbidi- ties and high-risk characteristics that can make cataract operations more diffi- cult. They will briefly review their as- signed condition, but more importantly, they will offer up advice for minimizing complications and maximizing outcomes in each situation. This inaugural issue will feature Uday Devgan, M.D., dis- cussing his approach to the manage- ment of posterior polar cataracts. Kevin Miller, M.D. challenging cases editor Or view the video of Dr. Devgan's procedure at www.eyeworld.org/replay.php. Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.)

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