This single-arm clinical trial assessed the ability of the Retina Implant Alpha AMS (Retina Implant AG) to restore vision in 6 patients with end-stage retinitis pigmentosa.

Study design

The prospective, investigator-sponsored, interventional trial compared vision with the implant turned on vs with the implant turned off in the same eye. Each of the 6 patients received the Alpha AMS implant in their worse-seeing eye, which had bare light perception or no light perception at study entry.

The main outcome measures were vision assessments, which included object recognition tasks, patient self-assessment of their mobility, as well as screen-based visual acuity testing, including basic light and motion testing as well as grading visual acuity.

Outcomes

During a 24-month follow-up period, the implant restored light perception and temporal resolution to all 6 participants. The ability to locate high-contrast tabletop objects was re-established in all but 1 participant, whose implant was damaged intraoperatively.

There were 2 incidents of conjunctival erosion, 1 macula-on-retinal detachment, and 2 cases of inadvertent damage to the implant during surgery.

Limitations

Because patients in this trial had bare light perception or no light perception at baseline, they may have had significant, permanent retinal damage prior to implantation. The surgery involves placing the implant underneath the fovea and is technically challenging. There were adverse events that arose due to the implantation process, such as conjunctival dehiscence or erosion and retinal detachment.

Clinical significance

Patients who are blind from retinitis pigmentosa may have partial restoration of some visual precepts with this device. These early findings suggest the Alpha AMS performs at least as well as the previous generation Alpha IMS device, and with increased longevity.