Approved retinal prostheses: comparison, current knowledge, and developments—a systematic review

Summary Background Recent epidemiological research showed that inherited retinal dystrophies are the leading cause of severe visual impairment among children and working adults across Europe, notably in Austria. Currently, available treatments are primarily supportive with limitations. However, promising new therapeutic approaches such as retinal prostheses offer prospects for addressing these challenges. Approved retinal prostheses are currently restricted to epiretinal and subretinal implants. Here, we analyze and compared the medical risks and subretinal enhancements in visual function of both systems considering their respective rehabilitative differences. Furthermore, we explore the current state of knowledge and future developments of retinal prostheses. Material and methods This systematic review is based on PRISMA‑P using diverse scientific databases. Only non-randomized clinical studies and case series were included. All included studies were individually assessed with the ROBINS‑I tool of the Cochrane Collaboration and the TREND checklist for bias assessment. Results Out of 564 screened records, 16 non-randomized controlled clinical studies were included, comprising eight on subretinal implants and eight on epiretinal implants. Data analysis revealed that epiretinal implants provided more consistent outcomes in motion detection and object localization, while subretinal implants showed greater variability with occasional superior gains in visual acuity but at the cost of higher complication rates. The overall bias risk was moderate. Conclusion Both prosthesis systems can restore basic visual functions but differ in consistency, safety profile, and methodological rigor. Further standardized, long-term studies are needed to enable reliable comparisons and optimize patient outcomes. A glimpse into the future promises many new therapeutic approaches, such as artificial intelligence-supported retinal prostheses.