Functional vision in the real-world environment with a 44-channel suprachoroidal retinal prosthesis

Abstract

Purpose : The Bionic Vision Technologies Australia suprachoroidal retinal prosthesis (“bionic eye”) has been shown to improve functional vision in patients with late stage retinitis pigmentosa (RP) in a first-generation trial in a laboratory setting. In a subsequent trial of a second-generation device (NCT03406416), we assessed whether patients with late stage RP could increase their performance in real-world functional visual tasks conducted with the prosthesis switched ON compared to OFF.

Methods : The Functional Low-Vision Observer Rated Assessment (FLORA) instrument was administered to three males (aged 39, 47 and 63) and one female (aged 66) before implantation and at 17, 20, 32, 44, 56 and 68 weeks after device fitting. The FLORA contains 13 self-reported and 35 observer-reported items. The ease of which participants completed each functional vision task was assessed with a four-point scale: impossible, difficult, moderate, and easy. The tasks were evaluated in four discrete domains: ‘Visual Orientation’, ‘Visual Mobility’, ‘Daily Life’ and ‘Interaction with Others’. The distribution of person-level domain scores has been summarised via mode.

Results : Three participants completed the FLORA up to 68 weeks, with one participant being lost to follow up at 20 weeks for reasons unrelated to the device. For all participants after 17 weeks, the mode ease of task score with the device switched ON was higher or equal to when it was switched OFF (Figure 1). In general, ease of task score increased over time with the device switched ON. Tasks from the ‘Visual Orientation’ and ‘Daily Life’ domains were the main contributors to this effect. Qualitative analyses revealed participant-reported improvements in mobility, functional vision, and quality of life with device switched ON.

Conclusions : Participants with late-stage RP implanted with the second-generation suprachoroidal retinal prosthesis demonstrated improved ease of task scores over time with device ON relative to OFF. Improvement of ease of task scores over time with the device ON suggests a learning effect. The device shows potential utility in everyday life, and further research into its real-world use is warranted.

This is a 2021 ARVO Annual Meeting abstract.

 

Figure 1. Mode Ease of Task Scores for each participant with the Device Switched ON and OFF over 68 weeks (Participants A – D) Post-Device Fitting. Participant D assessed until 20 weeks. *If bi-modal, higher mode presented.