Do retinal implants provide long-term efficacy, safety and improve quality of life? A systematic review

Retinal implants have emerged as interventions to partially restore functional vision such as light perception, motion detection or object localisation in patients with severe vision loss from degenerative retinal conditions, including retinitis pigmentosa (RP) and dry age-related macular degeneration (AMD).

To evaluate the long-term efficacy, safety and quality of life (QoL) impact of retinal implants with ⩾1 year of follow-up.

Following PRISMA guidelines, a systematic search was conducted (31st July to 31st August 2024) in Web of Science, PubMed, Medline, Scopus, Cochrane Library and Embase, using the terms: ('retinal implant' OR 'retinal prosthesis') AND ('long-term' OR 'follow-up') AND ('efficacy' OR 'safety' OR 'quality of life'). No publication date restrictions were applied. Eligible studies were in English, involved human subjects with retinal degenerations, and reported ⩾1 year follow-up. Risk of bias was assessed using the Critical Appraisal Skills Programme (CASP) cohort study checklist for most studies, as they involved prospective follow-up without randomisation or control groups. The Joanna Briggs Institute (JBI) critical appraisal checklist for case series was applied to studies with a case series design. Narrative synthesis was applied.

Thirteen studies met the inclusion criteria: 53.85% assessed epiretinal implants (Argus II), 30.77% subretinal (Alpha AMS and PRIMA), and 15.38% suprachoroidal (44 and 49-channel STS). Epiretinal implants improved visual function, with up to 89% better in SLT, 50%-56% in DOM, and 30%-40% reaching ⩾2.9 logMAR when activated. Subretinal implants enhanced light perception, localisation, and grating acuity (to 3.33 cycles/degree), with acuity of 20/460 and 20/550 in some cases. Suprachoroidal devices improved SLT, DOM and GVA. Adverse events were more frequent with epiretinal than other implant types. QoL outcomes improved, particularly in mobility, orientation, and daily tasks.

Retinal implants confer functional vision, but acuities remain below 20/200, and recipients continue to meet criteria for legal blindness. Given the high risk of bias, lack of controls and potential placebo effects, further high-quality evidence is needed to confirm their efficacy, safety and QoL impact.