Silicone ring addresses challenges of precise capsulorhexis creation

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A silicone ring-shaped device for assisting continuous curvilinear capsulorhexis creation provides a guide for precisely sizing and positioning the capsular opening.

Dr. Kahook

By Cheryl Guttman Krader; Reviewed by Malik Y. Kahook, MD

Denver-A new device for guiding anterior capsulotomy (Verus Capsulorhexis Device, Mile High Ophthalmics) is an easy-to-use option that will allow surgeons-regardless of expertise and operating environment-to size and center a continuous curvilinear capsulorhexis (CCC) better, and at minimal cost compared with a femtosecond laser, said its inventor, Malik Y. Kahook, MD.

“Data from multiple studies demonstrate that capsulorhexis size and location can affect visual outcome after cataract surgery secondary to their effect on IOL position,” said Dr. Kahook, The Slater Family Endowed Chair in Ophthalmology, vice chairman, clinical and translational research, and professor of ophthalmology, University of Colorado Anschutz Medical Campus, Denver. “However, capsulorhexis creation remains the most difficult step of cataract surgery, and successful capsulorhexis is especially challenging for ophthalmologists in training.

“The new device we developed addresses the steep learning curve of capsulorhexis,” he added. “We believe it will allow even residents performing their first cases to make the capsulorhexis consistently, and it will provide all surgeons access to the benefits that come with a better capsulorhexis without the cost and technical requirements of a femtosecond laser.”

Design of the device

The device is made of medical grade silicone and is doughnut-shaped, with a 5-mm central aperture and a micropattern etched on the silicone surface that contacts the anterior capsule. The inner opening provides a caliper for precise capsulorhexis sizing, the inside edge of the ring serves as a guide for the leading edge of the CCC, and the micropattern allows the device to adhere to the anterior capsule and remain stable once it is positioned.

Dr. Kahook and colleagues came up with various prototypes in trying to develop a device that would enable surgeons to perform capsulorhexis consistently. They settled on the doughnut-shaped ring for several reasons.

“It was simple to insert into the eye through a small incision and easy to position at the desired location,” Dr. Kahook said. “In addition, the inner aperture provided a caliper for targeted sizing, and the device remained in place without the need to exert any downward force other than filling the anterior chamber with viscoelastic.

“Compared with some of our other iterations, it also had the simplest design,” he said. “Avoiding extra hardware was important for cost containment, which was another important goal.”

The development of the new device is described in a published paper [J Cataract Refract Surg. 2014;40:822-830]. As reported in the article, bench-side testing in bovine and human eyes performed after filling the anterior chamber with viscoelastic confirmed that the device was self-adhesive to the capsule, remaining immobile despite application of tangential forces during creation of the rhexis (Figures 1 and 2).

However, it could be easily lifted and removed from the eye at the end of the procedure using a Sinskey hook.

“The micropattern that is etched on the bottom of the silicone essentially acts like an integrated brake system, holding the device on the anterior capsule,” Dr. Kahook said.

In bench-side testing, the CCC was successfully created using the Utrata forceps to pull along the internal edge of the silicone ring and without evidence of tears or discontinuities.

Malik Y. Kahook, MD

E: malik.kahook@ucdenver.edu

Dr. Kahook has a financial interest in Mile High Ophthalmics. The device has been licensed from the University of Colorado Anschutz Medical Campus, Denver, to Mile High Ophthalmics and will be sold for single use. All necessary premarketing testing has been performed or is being completed, and the product is expected to have a global release before the end of 2014.