Eye movements and reading with plus-lens magnifiers

Purpose: This study aimed to determine the eye movement parameter(s) that is primarily affected when fully sighted subjects use plus-lens magnifiers for reading. Methods: Two forms of plus-lens magnifier were used: hand-held and spectacle-mounted. Eye movements were recorded using an infrared limbal reflection system as subjects read passages of text with and without the magnifiers; Data were compared for a young age group and an elderly (education-matched) age group. Results: For both age groups, a sawtooth pattern of eye movements was observed and reading speed was significantly (p = 0.0001) reduced when using the magnifiers compared with reading without. Forward saccade length decreased significantly (p = 0.0001) and time for retrace increased significantly (p = 0.0001), but fixation durations were unaffected. The form of magnifier had no significant effect on reading speed or eye movement parameters. Conclusions: The reduction in reading speed that occurred when using the plus-lens magnifiers was primarily a result of decreased forward saccade length.