EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78712
April 2012 Complicated cataract cases Phacoemulsification of the rock hard cataract by D. Michael Colvard, M.D. Y ou don't have to travel to the Sudan, the outback of Australia, or western Mongolia to find dense cataracts. They exist in every market, including yours, and every cataract surgeon needs to have strategies for dealing with them. Like many eye conditions, dense brunescent cataracts like to travel in the company of other not- so-surgeon-friendly ocular and systemic co- morbidities. A partial list includes deep-set eyes, compromised corneas, poorly dilating pupils, and zonular laxity. If an eye has retinopathy of prematurity or has had a pars plana vitrectomy, both of which are known to accelerate nuclear sclerosis, the co-mor- bidity list might also include intraoperative trampolining of the lens-iris diaphragm from absent or liquefied vitreous. Many patients with rock hard cataracts are systemically unhealthy and poor anesthetic risks. Problems the ophthalmologist fre- quently encounters when removing dense brunescent cataracts include difficulty visu- alizing the anterior capsule for the capsu- lorhexis; prolonged phacoemulsification time, which puts the endothelium and the incision at risk; poor visibility, especially if an eye is deep set or the pupil does not di- late well; lens mobility; worsening zonular laxity during the procedure; a risk of tearing the capsule and losing lens fragments pos- teriorly; and trapping dense lens fragments in the ciliary sulcus, only to find them in the anterior chamber days, weeks, or months after surgery. All of these potential problems can be approached with proactive solutions. In this issue, D. Michael Colvard, M.D., shares some of the lessons he has learned handling rock hard cataracts. While no amount of reading anecdotes or the knowl- edge gained by others over a career can substitute for personal surgical experience, wise surgeons may find a few pearls in what Dr. Colvard has written. Kevin Miller, M.D., Complicated cataract cases editor Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) Or view the video of Dr. Colvard's procedure at www.eyeworld.org/replay.php. P hacoemulsification of the extremely dense cataract poses challenges for even the most experienced cataract surgeon. The ab- sence of a protective epinuclear layer, the paucity of cortex, the fragility of the capsule, and the lax- ity of the zonules all increase the risk of injury to the supportive struc- tures of the lens during surgery. Longer phaco times at higher energy levels, moreover, increase not only the risk of corneal endothelial dam- age but also the risks of mechanical or thermal injury to the iris or cornea. Successful surgical manage- ment of these cases requires plan- ning and careful attention to detail. I would like to address some of the specific surgical considerations pre- sented by the rock hard cataract and offer suggestions for the step-by-step management of the challenges pre- sented by these cases. Consider a scleral incision Once in a while, no matter how skilled you may be as a phaco sur- geon or how good the equipment may be, you will encounter a nu- cleus that is simply too dense to be emulsified. Or you may sense at a "Inside-out" continued from page 18 Subsequent surgical steps • Nucleus removal with slow motion phacoemulsification • Focal and multiquadrant hydrodissection for cleavage of sub-incisional epinucleus • Epinucleus removal with biman- ual irrigation and aspiration Comply with caution • Inadvertent injection of fluid in the subcapsular space leading to hydrodissection • Adequate depth should be achieved during sculpting • Avoid placing cannula at a su- perficial level • Sudden forceful cleavage of the polar opacity from the posterior capsule • Introduce cannula from the main incision and not through side port (paracentesis) • Avoid rapid buildup of hydraulic pressure/IOP • Controlled injection of a tiny amount of fluid within the cen- tral core • Stop injecting fluid once a golden ring is observed • Inadequate intralenticular cleav- age • Repeat injection of fluid using a right-angled cannula facing right and left, until a golden ring is noted Limitations • Cataracts with nuclear sclerosis greater than grade 3 Summary Inside-out delineation achieves pre- cise delineation of the central core nucleus from the epinucleus. Sur- geons can achieve desired thickness of the epinucleus bowl that protects the opacity and the posterior cap- sule. It avoids inadvertent injection of fluid in the subcapsular plane. EW References 1. Vasavada AR, Raj SM. Inside-out delineation. J Cataract Refract Surg. 2004; 30:1167-1169. 2. Osher RH, Yu BC, Koch DD. Posterior polar cataracts: A predisposition to intra-operative posterior capsular rupture. J Cataract Refract Surg. 1990; 16:157-162. 3. Vasavada AR, Singh R. Phacoemulsification with posterior polar cataract. J Cataract Refract Surg. 1999; 25:238-245. 4. Osher RH. Slow motion phacoemulsification approach (letter). J Cataract Refract Surg. 1993; 19(5): 667. 5. Fine IH, Packer M, Hoffman RS. Manage- ment of posterior polar cataract. J Cataract Refract Surg. 2003; 29:16-19. Editors' note: The authors are affiliated with Iladevi Cataract & IOL Research Centre, Raghudeep Eye Clinic, Ahmedabad, India. They have no financial interests related to this article. Contact information Vasavada: icirc@abhayvasavada.com Raj: shetalraj@yahoo.com certain moment that things are about to "go south," a sudden deep- ening of the anterior chamber, for instance, or undue difficulty in ma- neuvering the nucleus. When these things happen, the smart move is to bail and convert to ECCE. For this reason, it's a prudent move to per- form a scleral tunnel incision in cases with extraordinarily dense nu- clei, just in case the need to convert arises. Enhance visualization of the capsule Visualization of the anterior capsule is often a problem with highly dense cataracts. Staining the capsule with trypan blue provides far better visu- alization, allowing the surgeon to perform the capsulorhexis with greater safety and much more confi- dence. Avoid capsular/lenticular block Care must be taken to avoid capsular block during hydrodissection. When there is very little cortex, the large dense nucleus can act as a lid, lifting up with hydrodissection, occluding the anterior capsulotomy, and com- pletely blocking egress of balanced salt solution from the posterior to the anterior chamber. The posterior capsule in mature cataracts is often very fragile and can be broken easily with increased posterior pressure. For this reason it's important to gen- tly tap the nucleus back down after every hydrodissection maneuver to allow the balanced salt solution to slip around the nucleus and decom- press the posterior chamber. Beware of wound burn Special care must be taken to avoid wound burns. Always make sure that OVD is flowing readily into the phaco tip during aspiration before you even begin to use phaco power and watch carefully for "phaco smoke" during phaco, suggesting that there is impairment of outflow. Dense lens material can easily clog the phaco tip and result in excessive heating very quickly. At the first hint of obstruction, phaco must be stopped immediately. If the collagen of the incision overlying the phaco tip shows any evidence of whiten- ing, injury may already have oc- curred. At the first sign of obstruction, stop instantly, clear the obstruction, and if there is any evidence of thermal injury to the phaco entry site, move your incision continued on page 20 EW NEWS & OPINION 19