Presbyopic corneal inlay shows promise

October 15, 2009

Results from early clinical experience show the latest version of an investigational presbyopic corneal inlay is associated with efficacy and safety that translate to high patient satisfaction.

The corneal inlay is a microporous, optically clear, hydrogel 2-mm insert used in an additive procedure that addresses presbyopia by steepening the central cornea and increasing its power, said Dr. Barragan, director, Laser Ocular Hidalgo, Monterrey, Mexico. The inlay has the same refractive index as the cornea and is placed intrastromally in the nondominant eye, under a LASIK-type flap. The inlay is intended for use in patients aged 45 or more years who have emmetropic presbyopia with 20/25 or better distance uncorrected visual acuity (UCVA) and a near add requirement of 1.5 to 2.5 D.

Mexican, Canadian study

No losses of two or more lines of near or distance BCVA were seen at any follow-up visit, and the single adverse event that occurred in the series was a need for repositioning of a displaced inlay on the first day after surgery. The latter procedure was completed successfully and resulted in good vision.

"The manufacturer has redesigned the inlay by increasing its diameter from 1.5 to 2 mm in order to improve near and intermediate vision while avoiding compromise of distance UCVA," Dr. Barragan said. "The early clinical results indicate these goals have been achieved. Patient satisfaction with distance vision is strong, and at this point in our follow-up, 100% of patients stated they would have the procedure again."

Keith Holliday, PhD, vice president, research and development, ReVision Optics, Lake Forest, CA, told Ophthalmology Times, "We now have follow-up data for patients in this study out to 9 months that show the visual acuity outcomes and functionality remain stable. More recently, flaps have been created using [a femtosecond laser (IntraLase, Abbott Medical Optics)], and early results for these patients indicate it results in even better vision performance."

The microporous hydrogel material of the inlay is biocompatible and allows transmission of nutrients, oxygen, and water. When placed under a LASIK-type flap, the inlay is delivered onto a dry stromal bed and centered over the constricted pupil using an inserter designed to minimize corneal touch.

The inlay adheres to the dry cornea and is covered with the hydrated corneal flap.

"The surgical procedure for placing this inlay is very easy, and it can also be removed easily, if necessary," Dr. Barragan said.

The 38 patients whose data were analyzed had an average age of 49.4 years (range, 45 to 56 years), and preoperatively, their mean sphere, cylinder, and near add power were +0.38 D, –0.38 D, and +1.82 D.

The results reported by Dr. Barragan were based on data from 1-, 3-, and 6-month follow-up visits completed by 37, 22, and 7 patients, respectively. Mean preoperative near UCVA was about 20/60 and improved to 20/25 at all follow-up visits, representing an average gain of four lines. Mean intermediate UCVA improved by about two lines, from about 20/40 to 20/25.

"We are very encouraged that the excellent near and intermediate visual acuity results are consistent with patient reports on their functional vision," he said. "Patients are asked about their ability to perform a variety of near tasks, including reading instructions on medicine bottles, newspapers, magazines, dialing their cell phones, and examining their finger nails, as well as about intermediate tasks, including working at the computer, finding items on the kitchen shelf, using a wall calendar, recognizing photo portraits, and using a bathroom mirror. All patients report being able to perform all of these intermediate tasks and almost all of these near tasks without glasses."

Future trials

Dr. Holliday said that the corneal inlay recently obtained the CE mark in Europe, whereas it remains an investigational device in the United States. ReVision Optics said that it hopes to begin clinical trials in the United States later this year.

The work was performed in collaboration with David Lin, MD, and Simon Holland, MD, Pacific Laser Eye Centre, Vancouver, British Columbia.