Repeated mobility testing for later artificial visual function evaluation

The study investigates the utility of a newly designed mobility test for repeated testing of visual function in patients with severe visual impairment and future application in evaluating functional progress in patients with artificial vision. Ten subjects divided into three groups based on visual acuity (VA) ranging from light perception to 20/200 and reduced visual field (VF) were included in the study. The mobility test consisted of using a set of four different but structurally similar and relatively short mazes having a constant number of obstacles of various sizes. The subjects, divided into three groups by acuity, passed through each course several times. In general, the patients with better VA had a larger extent of VF. Average speed and number of contacts were recorded as measures of performance. The average passing times of the groups through the courses were significantly different (p = 0.03), which was influenced by VA and VF. There was no significant difference in average number of contacts between the groups (p = 0.15). The mobility test proved to be appropriate for gaining statistically relevant results in repeated individual testing of patients with severe vision impairment. Results show promise for use this mobility test as a tool for assessing visual function of patients undergoing implantation of a visual prosthesis for artificial vision.