Results from a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherired Retinal Dystrophies (RD)

Abstract

Purpose : We assessed safety and efficacy of a technically advanced subretinal electronic implant in end-stage RD in an ongoing prospective clinical multicenter trial

Methods : The new RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted subretinally in 15 RD-patients (age 55.2 +/- 10.2 y, mean +/- SD). Inclusion criteria were uncertain light localization or no light perception, intact inner retinal function and previous reading ability. Functional outcome measures included 1) screen-based standardized 2- or 4-alternative forced-choice tests of light perception, light localization, grating acuity and Landolt C-rings; 2) grey level discrimination; 3) performance during activities of daily living (ADL-table tasks).

Results : Implant-mediated light perception was observed in 14/15 patients. During the observation period (12 months) implant mediated localization of visual targets was possible in 13/15 patients. Grating acuity was 0.1 cpd (cycles per degree) in 4/15 ; 0.33 cpd in 5/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. Best visual acuity assessed with Landolt C- ring was 20/546 and 20/1111. Of 6 possible grey levels, pairwise presented 3 times, 12 +/- 2.5 out of 18 were discerned correctly (mean +/- SD, n=10). Improvements (power ON vs. OFF) of ADL table tasks were reported by 13/15 patients. Results were overall stable during observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movement of the implant, readjusted in a second surgery; 3 conjunctiva erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs) were transient and mostly of mild to moderate intensity.

Conclusions : Psychophysical and subjective data show that RETINA IMPLANT Alpha AMS is reliable, well tolerated and partially restores visual functions in the majority of patients. Compared with previous Implant Alpha IMS, longevity of the new Implant Alpha AMS has considerably improved with a similar efficacy profile as Alpha IMS. Alpha AMS has meanwhile been certified as a commercially available medical device, in Germany reimbursed by the public health system. Providing centers have been recruited in several European countries.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.