Influence of field of view in visual prostheses design: Analysis with a VR system

TL;DR

This study investigates how the field of view affects visual perception in prostheses, revealing that higher angular resolution in a smaller area improves recognition and response times, guiding future prosthesis design.

Contribution

The paper introduces a VR-based simulation to analyze the impact of field of view and resolution on visual task performance in prostheses, providing new insights for design optimization.

Findings

Accuracy and response time decrease with larger field of view.

Performance correlates with angular resolution, with diminishing returns beyond 2.3 phosphenes/degree.

Focusing phosphenes in a small area enhances perception despite reduced field of view.

Abstract

Visual prostheses are designed to restore partial functional vision in patients with total vision loss. Retinal visual prostheses provide limited capabilities as a result of low resolution, limited field of view and poor dynamic range. Understanding the influence of these parameters in the perception results can guide prostheses research and design. In this work, we evaluate the influence of field of view with respect to spatial resolution in visual prostheses, measuring the accuracy and response time in a search and recognition task. Twenty-four normally sighted participants were asked to find and recognize usual objects, such as furniture and home appliance in indoor room scenes. For the experiment, we use a new simulated prosthetic vision system that allows simple and effective experimentation. Our system uses a virtual-reality environment based on panoramic scenes. The simulator employs a head-mounted display which allows users to feel immersed in the scene by perceiving the entire scene all around. Our experiments use public image datasets and a commercial head-mounted display. We have also released the virtual-reality software for replicating and extending the experimentation. Results show that the accuracy and response time decrease when the field of view is increased. Furthermore, performance appears to be correlated with the angular resolution, but showing a diminishing return even with a resolution of less than 2.3 phosphenes per degree. Our results seem to indicate that, for the design of retinal prostheses, it is better to concentrate the phosphenes in a small area, to maximize the angular resolution, even if that implies sacrificing field of view.