Corneal Inlay Corrects Presbyopia, Preserves Distance Vision

Caroline Helwick

November 27, 2013

NEW ORLEANS — More than 10,000 patients with presbyopia from around the world have been treated safely and effectively with the KAMRA intracorneal inlay (AcuFocus, Inc), new data show.

The inlay is commercially available outside the United States, and the premarket approval review is currently under consideration by the US Food and Drug Administration.

"KAMRA corneal inlay implantation is a good treatment option for emmetropic and ametropic presbyopes, and also for post-LASIK presbyopes," said Minoru Tomita, MD, from the Shinagawa LASIK Center in Tokyo, who spearheaded the development of KAMRA. Patients with cataracts, at least those younger than 60 years, are also considered "good candidates for this inlay."

Although there are other corneal inlays, KAMRA might be unique, in that it allows patients to maintain good distance vision, Dr. Tomita told Medscape Medical News. "With other inlays, studies have shown that distance vision can worsen," he explained.

Dr. Tomita presented efficacy data for KAMRA here at the American Academy of Ophthalmology 2013 Annual Meeting.

In a separate presentation, John Vukich, MD, from the Davis Duehr Dean Center for Refractive Surgery in Madison, Wisconsin, reported results from a prospective nonrandomized clinical trial of KAMRA.

The inlay uses a pinhole effect to create greater depth of focus, allowing clear vision at near, intermediate, and far distances. The procedure involves the implantation of an inlay into a femtosecond-created lamellar pocket, where the polymer inlay (3.8 mm in diameter, 10 µm thick) is inserted. The flap is replaced over the inlay to hold it in place without sutures.

Pinhole Effect, Greater Focus

The eye with the implant remains emmetropic so both eyes work together for distance vision. The inlay has no effect on examination and imaging of ocular structures.

Dr. Tomita presented an analysis of more than 10,000 KAMRA corneal inlay implantations for the treatment of presbyopia; most were performed in Japan. For patients with ametropia, a simultaneous LASIK procedure allowed KAMRA to be implanted under the LASIK flap. For patients with post-LASIK presbyopia, KAMRA was implanted into the pocket interface.

At 2-year follow-up, ametropia patients had gained 8 lines of uncorrected distance visual acuity and 3 lines of uncorrected near visual acuity.

At 1-year follow-up, post-LASIK presbyopia patients had lost 1 line of uncorrected distance visual acuity and gained 3 lines of uncorrected near visual acuity at 1 year.

In both groups, mean uncorrected distance visual acuity was 20/20 and mean uncorrected near visual acuity was about 20/30 after implantation. There was no change in mean corrected distance visual acuity, which remained 20/16, or corrected near visual acuity, which remained about 20/25.

"Patients also reported high satisfaction and reduced dependence on reading glasses," Dr. Tomita said. "The surgery is very easy," he told Medscape Medical News. "I can do one of these procedures in 2 minutes, and can remove the inlay in 1 minute."

Although the device can be easily removed, it has been necessary in less than 1% of patients. "The removal rate is extremely low," he said.

Three-Year Results in Emmetropic Presbyopes

Dr. Vukich presented results from a prospective nonrandomized clinical trial conducted at 24 sites in the Asia-Pacific region, Europe, and the United States. KAMRA inlays were implanted in 507 patients 40 to 60 years of age with naturally occurring emmetropic presbyopia.

"Near and intermediate vision improved, while good distance vision was maintained," Dr. Vukich noted. "Long-term data show maintained visual gain."

At 3 years, mean uncorrected near visual acuity in the inlay eye was about 20/30, uncorrected intermediate visual acuity was 20/25, and uncorrected distance visual acuity was 20/20. Mean binocular uncorrected distance visual acuity was 20/16.

Uncorrected near visual acuity improved from a mean of about 20/65 to about 20/30 in the inlay eye between the preoperative and 1-month visit. This result was maintained out to 5 years. Vision was unaffected by the progression of presbyopia in the inlay eye and in both eyes. Uncorrected near visual acuity in the untreated eye showed a mean loss of 1 line over the same time period, Dr. Vukich reported.

The KAMRA inlay is "a revolutionary concept," said James Salz, MD, from the University of Southern California in Los Angeles and founding editor-in-chief of the Journal of Refractive Surgery.

"It's so nice that you can show this pinhole effect to patients in the office with a piece of paper," Dr. Salz told Medscape Medical News. He said he also likes the fact that distance vision is not affected.

"The question will be whether patients will want to pay for this," Dr. Salz added. He calculated the cost of the disc and fees from the surgeon and laser center, which would not be covered by insurance, to be upward of $3000 per eye. Others have predicted that the cost could be higher.

"I think there will be a market for it," he predicted. "Some people just hate wearing glasses, and they may well spend $3000 to get rid of them."

Dr. Tomita is a consultant for Schwind Eye-Tech Solutions, Ziemer Ophthalmic Systems AG, and AcuFocus. Dr. Vukich has consulted for AcuFocus, Abbott Medical Optics, Carl Zeiss Meditec, Optical Express, Optimedica, and STAAR Surgical. Dr. Salz reports financial relationships with Alcon Laboratories and NTK Enterprises.

American Academy of Ophthalmology (AAO) 2013 Annual Meeting: Presented November 15 (Dr. Vukich) and November 16 (Dr. Tomita), 2013.

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