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A U.S. FDA clinical trial is now under way to explore the potential of intracorneal inlay technology to correct presbyopia in emmetropic patients.
Patients at up to 20 centers nationwide are being recruited to receive the inlay (AcuFocus ACI 7000, AcuFocus Inc.), an approach that seeks to improve near and intermediate vision while preserving distance vision in the same eye. The target enrollment is 400, reported George O. Waring III, MD, FRCS, FRCOphth, here at the American Academy of Ophthalmology annual meeting.
"Because it is thin and flexible, it makes minimal change to the corneal curvature underneath the flap," explained Dr. Waring. "Once it is placed, it can be centered around the corneal light reflex or the pupil and the flap can be put back in place. Its optical function is similar to the effect achieved with the F22 stop on a camera."
Preliminary results from a multinational study of the corneal inlay show that the device is able to improve near vision without affecting distance vision in patients with emmetropic presbyopia, he said.
Omer Faruk Yilmas, MD, of Istanbul, Turkey, performed the surgery on 39 patients with an average age of 55 years. Before surgery, all were emmetropic with good distance vision and poor near vision. At 12 months' follow-up, the uncorrected distance visual acuity remained the same, on average. The uncorrected near visual acuity had been J6 and gradually improved to J1 and J2.
"There is a learning process with this technology," Dr. Waring said. "It takes the brain of the patient a while to figure out how to use this device, so there is a delay of weeks to months to maximum effect. There is, however, a final stability."
The device was considered extremely safe because no eyes that retained the device lost more than 2 lines of best spectacle-corrected visual acuity. In fact, all the patients who kept the device were spectacle-free except for one. Three patients in Turkey did require the device to be removed, one because of an epithelial defect from herpes and the other two patients because of the loss of some distance vision, he continued.
Preliminary FDA studies
Dr. Waring participated in the early FDA trials of the device with implantation in 10 patients with emmetropic presbyopia and normal corneas. Most patients were very pleased with the visual results of the inlay, with some comparing their vision to that of a 21-year-old, he said.
Besides its potential ability to improve near vision, the corneal inlay can be safely removed. The surgeon only has to lift the flap, remove the inlay, and replace the flap, Dr. Waring said.