Assessment of visual function in patients with gyrate atrophy who are considered candidates for gene replacement.

OBJECTIVE To assess the course of change of visual function outcome variables in 5 patients with gyrate atrophy before a gene replacement therapy clinical trial. METHODS The outcome variables selected were visual field sensitivity and electroretinogram amplitude. The course of change of these outcome variables was determined by calculation of their half-lives. RESULTS In the 4 to 6 years during which each patient was followed up for this study, median visual field half-lives were 17.0 years (static perimetry) and 11.4 years (kinetic perimetry). Median electroretinogram half-lives were 16.0 years (maximal response) and 10.7 years (flicker response). CONCLUSIONS The course of the decline of visual function outcome variables is frequently slow. Thus, a long-term clinical trial would be required to assess the efficacy of the intervention in the preservation of visual function.