Virtual reality simulation of epiretinal stimulation highlights the relevance of the visual angle in prosthetic vision.

Objective: Retinal prostheses hold the potential for artificial vision in blind patients suffering from outer retinal dystrophies. The optimal number, density and coverage of the electrodes that a retinal prosthesis should have to provide adequate artificial vision in daily activities is still an open question and an important design parameter needed to develop better implants.

Approach: To address this question, we investigated the interaction between the visual angle, the pixel number and the pixel density without being limited by a small electrode count. We implemented prosthetic vision in a virtual reality environment in order to simulate the real-life experience of using a retinal prosthesis. We designed four different tasks simulating: object recognition, word reading, perception of a descending step and crossing a street.

Main Results: The results of our study showed that in all the tasks the visual angle played the most significant role in improving the performance of the participant.

Significance: The design of new retinal prostheses should take into account the relevance of the restored visual angle to provide a helpful and valuable visual aid to profoundly or totally blind patients.