Custom iris prosthesis benefits aniridic patients

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A custom flexible, silicone iris prosthesis (CustomFlex, HumanOptics) provides visual and cosmetic improvements for patients with complete or partial aniridia.

Dr. Snyder

By Cheryl Guttman Krader; Reviewed by Michael E. Snyder, MD

Cincinnati-Five years of experience with in-the-bag implantation of a custom flexible, silicone iris prosthesis (CustomFlex, HumanOptics) demonstrates excellent clinical results for addressing iris defects not amenable to primary iris reconstruction.

“The artificial iris device markedly reduced light sensitivity and photic symptoms,” said Dr. Snyder, a faculty consulting surgeon and board of directors member, Cincinnati Eye Institute, Cincinnati, OH. “Some individuals also had significant improvement in best-corrected visual acuity, although that may be partly associated with the concomitant cataract surgery.”

Dr. Snyder reviewed findings from a series of 60 eyes of 48 patients with the iris prosthesis implanted during cataract surgery. The eyes in the series represented cases of congenital and acquired defects, including partial and complete aniridia. Postoperative follow-up ranged from 3 months to 5 years.

All of the cases were performed under compassionate use exemptions from the FDA. A U.S. multicenter FDA IDE trial of the device was launched in August 2013.

Significant reductions of iris defect-associated visual symptoms along with improvement in self-perceptions of body image were among the patient benefits, according to Dr. Snyder.

In addition, visual function was significantly improved in some patients. None of the devices needed to be explanted, and there was no evidence that the prosthesis increased susceptibility to complications that can occur in patients with iris defects related to underlying comorbid pathology.

Cosmetic appearance

“The cosmetic outcomes are also impressive,” Dr. Snyder said. “It should not be overlooked that improvement in the appearance of the eye had a tremendous positive impact on the patients’ psychosocial function.”

Each custom iris prosthesis is handcrafted so that its color matches a photograph taken of the fellow normal eye or, in patients with bilateral aniridia, any chosen eye. The pupil of the prosthesis measures 3.35 mm in diameter and features an undulated edge that replicates the pupillary frill of a natural iris. The devices are also molded so that their anterior surface mimics that of the natural iris.

“The appearance of these devices is so good that it is extremely hard to tell that a prosthesis is present when speaking to recipients from cocktail party distance,” Dr. Snyder said.

Implantation of the device

The device is implanted into the capsular bag during cataract surgery after removal of the crystalline lens. Each device measures 12.8 mm in diameter and is trimmed as necessary based on the size of the patient’s capsular bag. It is placed using an injection process akin to that used for implanting a foldable IOL.

A capsular tension ring is now placed routinely in all eyes.

“We learned that a capsular tension ring is necessary to ensure that the capsular bag maintains its shape over time so as to prevent the prosthesis from buckling or curling,” Dr. Snyder said. “With one exception, none of the eyes in which the prosthesis was implanted with a capsular tension ring developed any issues that could be related to the prosthesis.”

The exception involved a patient who had a thick capsular rind-like plaque causing significant shrinkage of the capsular bag as it contracted postoperatively, despite a standard capsular tension ring, causing focal buckling of the iris device in that meridian. The device was repositioned successfully with suture fixation, and the patient has remained with an excellent outcome since.

Michael E. Snyder, MD

E: msnyder@cincinnatieye.com

Dr. Snyder is a consultant for HumanOptics and is the medical monitor for the FDA IDE study. The device is unapproved and manufactured outside the United States. Consequently, the FDA has not determined the device’s safety, efficacy, or if the device has been manufactured according to FDA’s quality systems or other pertinent FDA regulations.

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