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Up Front | Jul 2003

Cataract Challenge

Congenital Cataract With Sectoral Iridectomy

A 58-year-old white male born with bilateral congenital cataracts had undergone bilateral optical iridectomies at age 4. In 1968, cataract surgery with IOL implantation in his amblyopic right eye had not produced any visual improvement. Ten years later, another physician had diagnosed the patient with bilateral glaucoma and prescribed pilocarpine for IOP control. The patient had tried to wear a toric contact lens in his left eye without success and had explored the possibility of laser refractive surgery to correct that eye's astigmatism. He was referred to our office with a chief complaint of a gradual reduction in the vision of his left eye along with bothersome glare and halos. He was taking Xalatan (Pfizer Inc., New York, NY) bilaterally for his glaucoma.

The examination revealed a visual acuity of finger counting at 6 inches OD and 20/125 OS with his current correction at distance. A diagnostic refraction improved the vision of his left eye to 20/70 with -0.25 +5.50 X 87, but glare testing reduced the acuity to less than 20/400. Keratometry revealed between 4.00 and 5.00 D of with-the-rule astigmatism in each eye, a finding confirmed by corneal topography. The patient's congenital nystagmus remained horizontal in vertical gaze and showed a prominent null point.

Biomicroscopy of the patient's right anterior segment showed a small cornea, pseudophakia, a large-sector iridectomy extending from the 10:30- to the 2-o'clock position, and vitreous filling the pupil. In his left anterior segment, an optical iridectomy spanned from the 7- to the 8:30-o'clock position. The left cataract was axial and characterized by a linear opacity extending from the posterior nuclear/cortical interface to the anterior capsule (Figure 1). Applanation tonometry measured 18 mm Hg OD and

23 mm Hg OS. Dilated ophthalmoscopy showed small optic nerves with a 0.4 cup OD and a 0.5 cup OS. The patient's maculae appeared normal, and indirect ophthalmoscopy revealed an operculated tear in the superotemporal periphery of his right eye. Biometry of the left eye disclosed an axial length of 20.45 mm, and the average keratometry measured 49.70 D.

1. Is there an increased risk of posterior capsular rupture in this case?
2. Would you attempt to correct the preoperative keratometric astigmatism?
3. What is the best approach to address the iris defect and the glare?

In the OR, we measured the cornea of the patient's left eye at only 10.5 mm in the horizontal diameter. Keratoscopy using the Hyde-Osher ruler (Ocular Instruments, Bellevue, WA) confirmed approximately 5.00 D of with-the-rule astigmatism. Using a diamond knife, we placed two 690-µm incisions around a 5-mm optical zone. Repeated keratoscopy revealed a marked reduction in the cylinder. We then added two incisions around a 6.1-mm optical zone at the same depth and irrigated the incisions with BSS (Alcon Laboratories, Inc., Fort Worth, TX). Keratoscopy showed a nearly spherical light reflex, which indicated that the majority of the eye's astigmatism had been corrected.1

With a guarded diamond knife, we created a temporal, near-clear corneal incision and then switched to a trifaceted diamond knife to extend the incision 2 mm anteriorly. We entered the anterior chamber with a No. 55 blade and instilled Healon5 (Pfizer Inc.). After creating the capsulorhexis with a bent 22-gauge needle, we performed gentle hydrodissection and hydrodelamination. We then introduced the phacoemulsification handpiece and used slow-motion parameters to divide, chop, and safely remove the nucleus.2 We aspirated the cortex with a silicone I/A tip and vacuumed the posterior capsule.

At this point, we enlarged the incision to 3.5 mm with a diamond keratome. Next, we introduced the artificial iris segment (Morcher type 96F; Morcher GmbH, Stuttgart, Germany) into the capsular bag under the protection of Healon5 and rotated the segment into the area where the iris was absent.3 After injecting a foldable +27.00 D SA60AT AcrySof lens (Alcon Laboratories, Inc.) into the capsular bag, we placed its haptics behind the prosthetic iris device. Using the silicone I/A tip, we first removed the Healon5 from behind the IOL and then from within the anterior chamber. After confirming that the incision was watertight, we instilled topical pilocarpine, Alphagan (Allergan, Inc., Irvine, CA), Xalatan, TIMOPTIC Sterile Ophthalmic Solution (Merck & Co., Inc., West Point, PA), Pred Forte (Allergan, Inc.), and QUIXIN (Santen Inc., Napa, CA). We discharged the patient in good condition and wearing a protective eye shield.

On the first postoperative day, the patient's UCVA had improved to 20/50, and his IOP was 18 mm Hg. The sector iris device was well positioned, and the IOL appeared centered (Figure 2). Keratometry disclosed a 4.00-D reduction in astigmatism, and the patient was pleased.

This case was extremely complex, and the patient's symptoms justified cataract surgery in his better eye. Although posterior polar cataracts have an associated defect in the posterior capsule, this opacity was located in the anterior two-thirds of the lens, a position that did not increase the risk of a posterior capsular rupture during the phacoemulsification procedure.

Dr. Osher has used corneal relaxing incisions since 1983. With 5.00 D of cylinder in the patient's eyes, we believed a more emmetropic pseudophakic refractive error would be beneficial despite mild refractive amblyopia.

The aim of implanting the iris prosthetic device was to reduce the patient's glare, which related to an inferior sector iridectomy. Although this prosthesis is currently unapproved in the US, our preliminary results with the device have been encouraging.

Marcílio G. Barros, MD, is a fellow in cataract surgery at the Cincinnati Eye Institute in Ohio. Dr. Barros may be reached at (513) 984-5133; mgbar@uol.com.br.
Robert H. Osher, MD, is a professor at the University of Cincinnati College of Medicine and is Medical Director Emeritus at the Cincinnati Eye Institute in Ohio. He is a consultant for Alcon Laboratories, Inc., and Pfizer, Inc. Dr. Osher may be reached at (513) 984-5133; rosher@cincinnatieye.com.
The authors received no public or private financial support pertaining to the information published in this article.
1. Osher RH. Transverse astigmatism keratotomy combined with cataract surgery. In: Thompson KP, Waring III GO, guest eds. Ophthalmology Clinics of North America. Philadelphia, Pa: Saunders; 1992:717-725.
2. Osher RH. Slow motion phacoemulsification approach. J Cataract Refract Surg. 1993;19:667.
3. Osher RH, Burk SE. Cataract surgery combined with implantation of an artificial iris. J Cataract Refract Surg. 1999;25:1540-1547.
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