Recognition speed using a bioptic telescope.

Purpose. This study sought to quantify the training and the asymptotic efficiency of novice users of spectacle-mounted bioptic telescopes. Methods. Fifteen subjects with simulated 20/200 central acuity were fitted with bioptic telescopes. We measured the speed with which subjects were able to use a bioptic telescope to locate and identify a small letter, which was presented peripherally in a crowded array of letters at 45° eccentricity. Both the target onset and its location were random. Subjects participated in four experimental sessions for a total of 500 (short session group) or 1000 trials (long session group). Results. After training, the letter recognition speed with a bioptic telescope decreased by about 800 ms. Most of the improvement, however, occurred within the first 150 trials. There were no systematic differences between groups. The asymptotic recognition speed with a bioptic telescope was about 1000 ms, 450 ms longer than the recognition speed in the same task but with 20/20 vision. Preliminary measurements suggest that these learning effects persist over a period of several years. Conclusions. Evidently, novice users can quickly acquire proficiency in using a spectacle-mounted bioptic telescope. This task could be used to train new bioptic telescope users in a safe environment and to evaluate their progress. (Optom Vis Sci 2008;85:1135-1141)