A 25-year-old, single woman with a history of monocular count-fingers amblyopia and exotropia from a white, congenital cataract requested cataract surgery for the leukocoria, which she found highly unappealing cosmetically. This otherwise confident, assertive, and attractive young professional felt self-conscious during social interactions because of her pupil's externally obvious white appearance. The slit-lamp examination showed a white, membranous cataract, but the remainder of her examination was unremarkable.
After staining the anterior capsule with indocyanine green (Akorn, Inc., Buffalo Grove, IL), the surgeon completed the anterior capsulorhexis, although the central anterior capsule adhered to the dense posterior capsular plaque. He manually aspirated the minimal, clear cortical material from the capsular bag's periphery in a dry-aspiration fashion within the anterior chamber, which was filled with Healon (Advanced Medical Optics, Inc., Santa Ana, CA). The surgeon's attempt to delaminate and peel the thick, rind-like plaque from the posterior capsule resulted in a central tear .
Keeping in mind the patient's strong motivation for improved cosmesis, how would you proceed?
CHRISTOPHER KHNG, MD
It is fortunate that an anterior capsulorhexis was successfully completed. At this point, any further attempt to dissect the thick membrane inherent in the posterior capsule should stop. Injecting a dispersive viscoelastic through the small, inadvertent posterior capsular opening may help keep the anterior hyaloid face intact and away from the posterior capsule.
The surgeon should use a cystotome to begin a tear in the posterior capsule in a new location where less fibrosis is present (eg, at the 8-o'clock meridian in Figure 1, peripheral to the fibrotic area) and bring it around toward the 2-o'clock meridian with capsular forceps. This maneuver should be completed in such a way as to encompass as much of the fibrotic capsule as possible within the tear. The thick fibrotic bands between the 11- and 2-o'clock meridians may be lysed with curved intraocular scissors inserted through the main corneal incision. During this process, the surgeon should keep the anterior chamber adequately pressurized with a viscoelastic agent so as to prevent vitreous prolapse. One may enhance the retention of viscoelastic within the anterior chamber by injecting a dispersive agent just within the internal ostium of the corneal incision. Because the aim would be the removal of all white fibrotic membrane within the pupillary aperture, clearance should reasonably be extended peripherally to a diameter of approximately 4.5 to 5.0mm to account for the mesopic pupil size of such a young individual.
If it were not possible to complete an appropriately sized, roughly circular opening in the posterior capsule with the aid of scissor-transection of the fibrotic bands, an alternative approach would be to use a vitreous cutter through a pars plana sclerostomy. One could place a butterfly needle or other irrigating tip through a separate limbal paracentesis incision to provide infusion into the anterior chamber. After performing a limited anterior vitrectomy, the surgeon should set the vitrector to irrigation-cut-aspiration. Once the vicinity of the posterior capsule is free of encumbrance from vitreous attachments, one should change the setting to irrigation-aspiration-cut and turn the vitrector's port toward the posterior capsule for removal of the white membrane.
After clearing this membrane from within the 5-mm pupillary zone, the surgeon may inject a three-piece foldable IOL, place its haptics into the sulcus, and trap the optic within the anterior capsulorhexis. This technique will ensure good centration of the lens and reestablish a complete diaphragm, thus preventing vitreous prolapse. A round-edge silicone IOL may be preferable in this young patient, because this lens material and design may be less prone to dysphotopsias.1 Although amblyopic, the visual potential in such an eye may sometimes be surprisingly better than anticipated after cataract removal.
Referring the patient to a strabismologist at a later date for correction of the exotropia would further enhance her eye's cosmetic appearance and possibly also improve its visual function.
RICHARD J. FUGO, MD, PhD
My surgical choices in this fascinating case would differ from a classic approach. The procedure at this point depends on the surgeon's level of experience. The Fugo Blade (Medisurg Ltd., Norristown, PA) creates a plasma plume that ablates tissue (breaking it into small fragments, much like with an excimer laser) (Figure 2). Master surgeons have tackled similar plaques with specially modified Fugo Blade tips that are similar to the tips my colleagues and I are using in vitreoretinal surgery. A small plasma plume ablates the plaque. After treating the upper white portion of the opaque area, we have found a small, base transparent membrane that can be lifted off the posterior capsule with a forceps. The situation is analogous to an oyster, which deposits material onto a substrate in order eventually to produce a pearl.
Someone new to the Fugo Blade can manage the posterior plaque in a simpler fashion. The surgeon could perform a large 360º posterior capsulotomy while being sure not to touch the vitreous with the unactivated Fugo Blade's incising tip. Doing so could damage the membranous cisternal vitreous structure, as elegantly demonstrated in a 20-year study by Jan Worst, MD.2,3 If the cisternal structure remains intact, a vitrectomy may be unnecessary, and the case will essentially be complete. Damage to the vitreous cisterns may require a vitrectomy. (Videos of the procedures are available on CD-ROM and may be obtained by calling Medisurg Ltd. at (610) 277-3937.)
GUILLERMO ROCHA, MD, FRCSC
Although the patient's motivation for the cataract procedure was improved cosmesis, her ophthalmologist would certainly have discussed the risks of, benefits of, and alternatives to surgical intervention with her. In addition to the intraocular surgery, her ophthalmologist should have explained that a secondary strabismus procedure would be needed to resolve her exotropia. Finally, it cannot be overstressed that the patient has to be aware that her visual prognosis postoperatively will be poor.
After the patient decided to proceed with the elimination of her leukocoria, I would have initially proceeded exactly as described and tried to perform as routine a cataract extraction as possible. Upon noticing a tear in the posterior capsule, I would maintain the anterior chamber's pressure by injecting more viscoelastic. Most likely, vitreous is not actively protruding through the opening. The main concern in this case is that the anterior and posterior capsules have become adherent over time, and thus my focus should be the patient's main motivation for surgery. Leaving those white membranes will not solve her problem. I would therefore create a small conjunctival peritomy followed by a sclerotomy made with a 20-gauge microvitreoretinal blade. A superotemporal location, 3mm posterior to the limbus, would be ideal, because the patient's upper eyelid would cover the wound. A 23-gauge irrigating cannula through a 1-mm clear corneal paracentesis could provide irrigation while I inserted an automated vitrector through the sclerotomy in order to perform an anterior vitrectomy. The goal would be to provide a clear central pupil.
Initially, the vitrector should be set at a lower cutting rate to adequately engage the capsular and lenticular remnants. I would raise the cutting rate as high as possible (depending on the machine used) while minimizing the level of aspiration to complete a central anterior vitrectomy after eliminating the fragments. This approach would prevent excessive traction on the vitreous base. Next, I would constrict the pupil with a miotic such as intraocular acetylcholine. I would ensure that there were no tractional vitreous strands through the pupillary area, because they would further distort a cosmetically round pupil.
With respect to the IOL, the choices would be to place no lens or to fixate an IOL in the anterior chamber, iris, or sulcus. An ACIOL would require a peripheral iridectomy and might emit reflections, both of which this patient might not like. An iris-fixated lens could result in an ovoid pupil. A transsclerally sulcus-fixated lens would probably not be necessary in this situation and might be associated with visible scarring postoperatively. If there were adequate support to place a lens in the sulcus, I would do so. Otherwise, I would leave the eye aphakic. I would ensure adequate pupillary constriction by using intraocular acetylcholine prior to completing the case. After the patient recovered from the procedure, I would recommend strabismus surgery to correct the exotropia, if desired.
Section Editors Robert J. Cionni, MD; Michael E. Snyder, MD; and Robert H. Osher, MD, are cataract specialists at the Cincinnati Eye Institute in Ohio. They may be reached at (513) 984-5133; firstname.lastname@example.org.
Richard J. Fugo, MD, PhD, is Director of the Fugo Eye Institute and is Chairman of the Department of Ophthalmology at Mercy Suburban Hospital, both in Norristown, Pennsylvania. He has a financial interest in the Fugo Blade and Medisurg Ltd. Dr. Fugo may be reached at (610) 277-3937; email@example.com.
Christopher Khng, MD, is a subspecialist in complex cataract surgery and anterior segment reconstruction at The Eye Institute, Tan Tock Seng Hospital, Singapore. He is also a clinical tutor with the National University of Singapore. He states that he holds no financial interest in the products or companies mentioned herein. Dr. Khng may be reached at +65 6357 7726; firstname.lastname@example.org.
Guillermo Rocha, MD, FRCSC, is Medical Director at GRMC Vision Centre in Brandon, Manitoba; Assistant Professor at the University of Manitoba; and Adjunct Professor at the University of Ottawa Eye Institute in Canada. He states that he holds no financial interest in the products or companies mentioned herein. Dr. Rocha may be reached at (204) 727-1954; email@example.com.
1. Davidson JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg. 2000;26:1346-1355.
2. Worst JGF. The Vitreous Body in 3-D. Groningen, Holland: Ophtec BV; 2001.
3. Worst JGF, Los LI. Cisternal Anatomy of the Vitreous. Amsterdam/New York: Kugler Publications; 1997.