Abstract
Purpose: :
To determine how Argus II users’ performances on different visual tasks correlate with each other.
Methods: :
The Argus II retinal prosthesis system includes a 10 x 6 electrode array implanted epiretinally, a tiny video camera mounted on a pair of glasses, and a small external computer that processes the video and determines the stimulation current of each electrode in real time. We determined the pairwise correlations for several different performance measures of Argus II users, including their ability to determine the direction of motion of a moving object, their visual acuity, their ability to discriminate pairs of electrodes, their ability to follow a line on the floor, and their ability to find a door.
Results: :
The pairwise correlations of the outcome measures fall into two groups: tasks that require a certain degree of spatial vision, and tasks that can be performed by scanning the visual scene. There are no significant pairwise correlations between measures falling in different groups.
Conclusions: :
The results show that the degree of success in different tasks correlate based on the method in which they are solved (spatial vision vs. scanning). The lack of correlations between tasks requiring different skills suggests that improvement in one set of tasks does not preclude improvement in other tasks. Therefore, targeted rehabilitation programs can be customized for Argus II users to develop specific skills and strategies. To our knowledge, this is the first quantitative assessment of visual performance correlations in a larger study group.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00407602
Keywords: visual acuity • shape, form, contour, object perception