Telescope Implant Improves Vision in Macular Degeneration

By Jennifer Anderson

A new ruling by the FDA makes it possible for younger patients with end-stage macular degeneration to regain central vision through a telescope implant.

In October the FDA expanded access to an implantable miniature telescope to include patients as young as 65. Previously, the pea-sized telescope had been approved only for patients aged 75 and older.

The telescope is the only FDA-approved surgical device for the most common form of end-stage macular degeneration, says Marc H. Levy, MD, a neuro-ophthalmologist at the Sarasota Retina Institute in Florida, who has implanted such devices in more than a dozen patients.

"Lowering the age has allowed us to reach out to many more patients who we otherwise are just treating with vitamins, glasses, and cataract surgery," Levy says. He noted 65 as an "appropriate age" for implanting the telescope because patients generally have had fewer strokes or other medical conditions that might make them ineligible for the telescope implant.

"They still have end-stage macular degeneration," he says, "but their eyes are [generally] healthier and their corneas are clearer."

Doubling of Visual Acuity
At 4 mm long and 3 mm in diameter, the implantable miniature telescope—known as IMT—fits inside the capsular bag of the eye and replaces the natural lens. Allen Hill, president and CEO of VisionCare Ophthalmic Technologies in Saratoga, California, the company marketing the telescope in the United States, describes the device as "an elegant, miniaturized [version] of Galileo's telescope." 

Hill explains that the telescope, designed by an inventor in Israel, relies on two ultraprecision microlenses that do the bulk of the work. Three air spaces that also function as lenses provide the refractive power of the telescope.

Those lenses, combined with the front and rear telescope windows, make for a total of six lens surfaces. "That's important," Hill says, "because if we just take the microlenses out and put those in the eye, we would not have nearly the refractive power we have."

The telescope has been approved for patients aged 65 and older with a visual acuity no better than 20/160 and no worse than 20/800, or what Hill describes as severe to profound impairment.  Once the telescope is installed, patients should experience a four-line change on a visual acuity chart—what Hill describes as "a more than doubling of visual acuity."

Thus a patient diagnosed with vision of 20/160 should achieve vision around 20/80 with the telescope implant, he says.

Patients also must have scarred maculas from end-stage wet or end-stage dry macular degeneration, and involving both eyes. The telescope is installed in the eye with the better vision and functions in conjunction with the cornea and similar to the kind of fixed-focus lens of a camera.

One Size Fits All
The telescope does not cure macular degeneration, Hill says. But it does send a high-resolution, magnified 2.7 times, over the macula, the central portion of the retina that is comprised of high-resolution light-sensing cells that allow for central vision. The telescopic image more than covers the damaged portion of the macula, as well as a large area of the retina surrounding the macula, essentially restoring the lost central vision.

There is also a telescope magnifying 2.2 times, which primarily is used for patients outside the United States who are eligible for the telescope with less severe vision loss.

"They are still one-size-fits-all," Hill says of the telescopes. No one receives an individual prescription. After it is implanted, patients still may need glasses to adjust for near and far vision.

The cost of the device itself is approximately $15,000, Hill says. But because most patients are insured by Medicare, out-of-pocket costs should be minimal.

The telescope is intended to be permanent and is made of biocompatible plastic and quartz glass, Hill says. While no patients have had a telescope for more than a dozen years, "we do know how these materials perform in humans over long periods of time," Hill says.

It has been implanted in approximately 500 patients, primarily in the United States but also in Europe and other markets, Hill says. He estimates that 200,000 people in the United States are eligible for the telescope, which means they have both the bilateral end-stage "dry" macular degeneration and severe vision impairment.

Another 20,000 to 30,000 new cases of people with macular degeneration and vision of 20/160 or worse are diagnosed each year, he says.

The company's focus had been on hospital outpatient departments due to limitations on reimbursement, Hill says. With reimbursement rules changing, the company in January will begin working with ambulatory surgery centers, he says.

Expanding the Field of Vision
Once implanted, the telescope allows patients to focus on, for example, reading and recognizing people when they come to the door, explains David S. Boyer, MD, a retina specialist with Retina-Vitreous Associates Medical Group in California.

One drawback is that the eye housing the telescope loses all peripheral vision, leaving that task to the other eye, Boyer says. Because vision between the eyes overlaps, he estimates total peripheral vision loss at just 15%.

"It's not perfect vision, but it's certainly better than what they've had, and it improves their quality of life," Boyer says.

Indeed, before the telescope, patients with end-stage macular degeneration had only external magnifiers as visual aids, Levy explains. External magnifying glasses and thick glasses are not only unsightly and label people as visually disabled, he says, but they also restrict the field of vision to only six degrees. At a football game, for example, binoculars might enable sight of the quarterback and linemen but not the wide receivers.

By putting the magnification directly into the eye, the field of vision is expanded to 24 degrees, and patients are able to use their eye movements, rather than turning their head, to look around.  "It actually does give you back central vision because images are three times larger," Levy says.  "The image is larger than the central blind spot."

Only a trained observer would notice the telescope in the eye, he says. "Mostly it is behind the colored part of eye. You might see reflection in the eye but won't pay much attention to it."

Independent Living
Levy estimates that about 18 million people in the United States have macular degeneration and that, of those, approximately 500,000 aged 60 and older have bilateral blindness due to end-stage macular degeneration.

Candidates for the telescope must have an eye with enough depth to house the device, cataracts still in place, and no other major medical conditions. Once these requirements are met, they typically would meet with a low-vision optometrist, who works with a patient using magnifiers to determine how well he or she might adapt once the instrument is implanted.

If all the medical requirements fall into place, a corneal surgeon implants the telescope, and an occupational therapist follows up to ensure the safety of a patient's environment and the ability to move around easily without bumping into furniture or other hazards.

The surgery takes about an hour, and patients use eye drops afterward, technically for six weeks but Levy said the drops have been improved to the extent that his most recent patient was able to discontinue them after only three weeks. 

Once implanted, the telescope is intended to be permanent, Levy says. His first patient, who participated in the clinical trials, is now in her upper 80s, lives in Sarasota, and has been using the telescope for 11 years. "She's doing great; very independent," Levy says.

As the technology improves, newer models of the telescope will be less bulky and easier to implant, Levy says, leading to even faster surgery and rehabilitation process.

— Jennifer Anderson is a freelance health and science writer based in Falls Church, Virginia.