Implantable Miniature Telescope retains positive results in 5-year follow-up

All patients had significant visual acuity gains at 5 years, but younger patients retained more vision and had fewer adverse events.

Issue: September 10, 2015

The Implantable Miniature Telescope showed favorable safety and efficacy outcomes for treating end-stage age-related macular degeneration over the long term, particularly in patients younger than 75 years old, according to a study.

The IMT (VisionCare Ophthalmic Technologies) is a fixed-focus telescopic system that enlarges visual objects in a patient’s central visual field.

“The IMT telescope can improve vision in some patients with bilateral vision loss from central geographic atrophy or end-stage wet macular degeneration about to undergo cataract surgery,” lead author David Boyer, MD, told Ocular Surgery News.

The prospective, open-label, multicenter clinical trial, a continuation of the 24-month IMT-002 study, evaluated 63 patients with the IMT 60 months after surgery, with 31 patients ranging from 65 to 74 years old in group 1 and 32 patients age 75 years or older in group 2.

Younger age yields better results

At 24 months, mean improvement in best corrected distance visual acuity was 3.2 lines. At 60 months, mean improvement in best corrected distance visual acuity was 2.4 lines, with 62% of patients maintaining a two-line improvement. Retention of visual acuity gains was higher in group 1, with 58% maintaining three lines or more at 60 months.

Improvement in quality-of-life scores was significant in both groups but higher in group 1.

Group 2 had a higher cumulative incidence of complications in 13 of 15 categories and more adverse events in 11 of 14 categories.

“The 5-year data show retention of visual acuity gains over an extended period of time after implantation with the IMT,” Boyer said. “Both younger and older patients had clinically significant visual acuity gains at 5 years, though the younger patients retained more of the vision gains at 5 years and experienced somewhat fewer adverse events.”

Mean endothelial cell density was 1,995 cell/mm² 3 months after implantation, with an acute loss of 20%. In the extension study, chronic loss was 3% per year, with less endothelial cell density loss in group 1 vs. group 2.

The IMT was removed from one patient in group 1 and 10 patients in group 2.

“Few lenses needed to be explanted because of patient dissatisfaction,” Boyer said. “Corneal problems were identified in a small number of patients.”

Next step for IMT

Boyer suggested that the ideal patient for the IMT is younger than 75 years of age and does not want to drive but is motivated to read or see people’s faces.

“The 65- to 75-year-old is more apt to be able to adapt to the lens and is probably more motivated,” he said.

As a next step, Boyer recommended cataract surgeons or retina specialists should offer IMT surgery to more patients.

“Patients need to undergo a complete evaluation by a low vision center or specialist and be offered a simulation that mimics the implant so they can actually see the potential treatment benefit themselves, before surgery, so they understand what the treatment is capable of doing,” he said.

Because the IMT has shown retention of visual gains over an extended period of time, with favorable outcomes in a younger cohort of patients, Boyer is hopeful about improving patients’ central visual fields using the implant.

“Five years ago we would tell these patients there was no medical or surgical options to help their vision,” he said. “Today we have an FDA-approved device, it is Medicare approved, and now with the long-term data, that all may provide significant visual benefit for our patients living with central blindness when no other options to improve visual acuity are available.” – by Kristie L. Kahl

Reference:
Boyer D, et al. Clin Ophthalmol. 2015;doi:10.2147/OPTH.S86208.

For more information:
David Boyer, MD, can be reached at Retina-Vitreous Associates Medical Group, 9001 Wilshire Blvd., Suite 301, Beverly Hills, CA 90211; email: vitdoc@aol.com.

Disclosure: Boyer reports no relevant financial disclosures.