Telescope Implant Improves Vision in Macular Degeneration

by Kathleen Louden
(Chicago, Illinois) — People with end-stage age-related macular degeneration (AMD) have improved visual acuity and quality of life after receiving an intraocular implant containing a tiny telescope in 1 eye, new research shows. An ophthalmologist who participated in the clinical trials presented the unpublished results here at the American Academy of Ophthalmology and Middle East Africa Council of Ophthalmology 2010 Joint Meeting.

The telescope implant improves vision in "a disease in which the patient is legally blind and has no surgical or medical alternatives," the presenter, Stephen Lane, MD, told Medscape Medical News. He was a medical monitor for the pivotal trials and is an adjunct professor of ophthalmology at the University of Minnesota, Minneapolis.

In July, the US Food and Drug Administration approved the telescope implant, also called the implantable miniature telescope (VisionCare Ophthalmic Technologies), to improve vision in some patients with end-stage AMD.

Telescope Magnifies Images More Than 2 Times

"The reason why this [device] works is a magnification effect, so the central scotoma can be overcome," Dr. Lane told meeting attendees.

This pea-sized implant, which replaces the natural lens, magnifies images greater than 2 times and projects the images onto a healthy part of the retina, according to the device manufacturer. It is available in 2 models: 1 that provides 2.2 times the magnification and another that gives 2.7 times magnification. Patients use the eye that received the implant for central vision and use the untreated fellow eye for peripheral vision.

To be eligible for this class 3 medical device, patients must have bilateral geographic atrophy or "post-wet" AMD disciform scars and must not yet have had cataract surgery, although they can have cataract, Dr. Lane said. Other eligibility criteria, according to the US Food and Drug Administration, include age 75 years or older and "stable severe to profound vision impairment" resulting from bilateral central scotoma.

In a multicenter clinical trial of more than 200 patients who received the implant, the mean best corrected visual acuity before implantation was worse than 20/300, Dr. Lane said. More than 80% of patients had at least a 2-line improvement in visual acuity on the Snellen chart 1 year after surgery, and 46% of patients improved 4 lines or more at 1 year, he reported. Most of those patients, according to Dr. Lane, maintained their improved visual acuity 2 years postoperatively (75% with 2 lines or better and 43% with 4 or more lines of improvement).

"Quality of life gains also are clinically meaningful," Dr. Lane said. "Patients were less dependent, better able to recognize people, and better able to...do activities of daily living."

Endothelial Cell Loss Possible

A possible complication of the implant is the loss of corneal endothelial cells. In the study, there was a 20% loss of epithelial cells, which Dr. Lane called "a little high." He said ophthalmologists should inform their patients that substantial endothelial cell loss can lead to corneal decompensation and the need for a corneal transplant.

A Michigan ophthalmologist who did not participate in the studies, George Williams, MD, said in an interview that study investigators told him that most patients in the studies tolerated the implant well and found it very helpful.

However, the device is for "a select group of patients with end-stage AMD," said Dr. Williams, chairman of the Department of Ophthalmology at Oakland University William Beaumont School of Medicine, Royal Oak, Michigan.

He mentioned, as did Dr. Lane, that patients need to undergo an evaluation to determine whether they can benefit from this device, which involves a trial with an external telescope.

"Only 1 in 5 patients who are screened actually end up getting the device," Dr. Williams told Medscape Medical News.

After the surgery, patients must receive training with a low-vision specialist. "It's hard to walk around with a telescope in your eye," Dr. Williams said.

Patients who did not tolerate the implant were those who could not adjust to using 1 eye for near-vision tasks and the other eye for distance vision, Dr. Lane said during the meeting.