Development and Validation of a Portable Visual Navigation Challenge for Assessment of Retinal Disease in Multi-Centered Clinical Trials

Abstract

Purpose : Traditional visual function endpoints used to evaluate retinal disease often are not sensitive to detect clinically meaningful changes in visual function in patients with vision loss from an inherited retinal disease. The goal of this study was to create a metric which can provide a reproducible measure of functional vision in a setting that can be applied to multi-center clinical trial protocol.

Methods : The visual navigation challenge (VNC) employs a homogeneous, modifiable lighting environment to an area featuring marked paths and a series of physical obstacles. Subjects were asked to navigate courses under a range of light levels. Validation included testing of normal subjects and subjects with goggle-simulated visual impairment for modeling of mild or severe retinitis pigmenta (RP).

Results : Light levels were measured over the entire VNC course at intensity settings from 1-400 lux; deviations in lux values were 2.3-7.5% over the entire area. Navigation times for normal, mild RP and severe RP displayed consistent differences across all test light levels (see figure), and showed significant differences between these groups by paired t-test (p < 0.05 for all points).

Conclusions : We have developed and validated a visual navigation challenge designed to assess visual function in a simulated “real-world” setting, immersing a patient in a 360-degree visual challenge environment with obstacles and varying lighting levels. Use of the Ora-VNC can differentiate simulated inherited retinal disease states. This mobile system (including lighting) facilitates its use in multi-center clinical trials.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.