Abstract
Purpose::
This work is related to the efforts of the Boston Retinal Implant Project to develop a sub-retinal prosthesis to restore vision to the blind. The purpose is to compare, propose and discuss a battery of testing methods that can be used to: 1) assess pre- and post-operative visual function; 2) optimize rehabilitative potential of the patients; and 3) establish developmental criteria aimed at identifying candidates for implantation.
Methods::
We have carried out an analysis of testing methods described by any of the research groups that are developing a retinal prosthesis, particularly those with on-going human clinical trials. This analysis included an exhaustive literature search of published data to identify methods of visual function assessment and rehabilitative strategies that have been considered by the groups. Our search included all publications available in the English language or translated that were found by Internet searchers pf the Pub Med, National Institute of Health, National Library of Congress as well as personal communications from many investigators who were contacted individually.
Results::
Using retrospective analysis, our group has compiled a battery of tests designed to asses pre- and post- operative visual function. These tests represent a combination of existing strategies as well as novel methods that include measures of quality of life and assessments of the contribution of sensory compensatory processing by the tactile and auditory systems. We propose that selection criteria for an "ideal" candidate should be strongly influenced by a careful assessment of the compensatory neuroplastic changes that follow visual deprivation. Our analysis has also led us to develop a rehabilitative training platform in which tactile and auditory information are presented in conjunction with visually presented stimuli, the premise of which rests upon the fact that sensory stimuli presented in conjunction will facilitate overall sensory perception and the potential benefit that would be derived from electrical stimulation with a prosthesis. The specifics of our proposed battery of tests will be presented.
Conclusions::
We believe that such a multi-faceted approach may better characterize the full range of pre-operative disability as well as the potential post-operative functional gains that could be realized by prosthetic intervention.
Keywords: neuro-ophthalmology: cortical function/rehabilitation • plasticity • visual impairment: neuro-ophthalmological disease