A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Interim Clinical Trial Results

Purpose: To report the initial safety and efficacy results of a second-generation (44-channel) suprachoroidal retinal prosthesis at 56 weeks after device activation. Methods: Four subjects, with advanced retinitis pigmentosa and bare-light perception only, enrolled in a phase II trial (NCT03406416). A 44- channel electrode array was implanted in a suprachoroidal pocket. Device stability, efficacy, and adverse eventswere investigated at 12-week intervals. Results: All four subjects were implanted successfully and there were no devicerelated serious adverse events. Color fundus photography indicated a mild postoperative subretinal hemorrhage in two recipients, which cleared spontaneously within 2 weeks. Optical coherence tomography confirmed device stability and position under the macula. Screen-based localization accuracy was significantly better for all subjects with device on versus device off. Two subjects were significantly better with the device on in a motion discrimination task at 7, 15, and 30 degrees/s and in a spatial discrimination task at 0.033 cycles per degree. All subjects were more accurate with the device on than device off at walking toward a target on amodified door task, localizing and touching tabletop objects, and detecting obstacles in an obstacle avoidance task. A positive effect of the implant on subjects' daily lives was confirmed by an orientation and mobility assessor and subject self-report. Conclusions: These interim study data demonstrate that the suprachoroidal prosthesis is safe and provides significant improvements in functional vision, activities of daily living, and observer-rated quality of life. Translational Relevance: Asuprachoroidal prosthesis canprovide clinically useful artificial vision while maintaining a safe surgical profile.

Automated summary

The study investigated the safety and efficacy of a second-generation suprachoroidal retinal prosthesis in four subjects with advanced retinitis pigmentosa. The results showed significant improvements in functional vision and quality of life for the subjects after device activation, indicating the potential clinical usefulness of this prosthesis.