Visual search training in subjects with severe to profound low vision

Effects of practicing on feature search tasks (a 2 degrees square target amid 1 degrees square distracters) for 5 days were compared between 45 visually impaired (VI) subjects with severe to profound low vision and 23 age-matched normal controls (NV). Search accuracy and speed improved in both groups. VI subjects had larger training gains than NV subjects, but their proportional gains were similar to that of NV subjects. There were no significant differences in training effect at different set sizes in both groups. Search performance on a 40 degrees field improved more than that on a 10 degrees or 20 degrees field in VI subjects, but not in NV subjects. No significant change was found between day 5 and 1-month follow-up. The fact that feature search training is equally efficient in VI and NV subjects encourages development of general purpose perceptual training protocols for low vision rehabilitation.