Abstract
Low vision patients with central scotoma must utilize their intact peripheral vision to execute tasks that are normally achieved with the fovea. Ophthalmologists specializing in low vision have observed that the severity of impairment (i.e. extent of scotoma) does not necessarily determine how well a patient is able to cope with the tasks of daily living. The objective of this study is to determine to what extent eye movement strategies can compensate for loss of vision in patients with bilateral central scotoma. Matched for acuity and scotoma properties, “High” and “low” performing patients were identified with the MNRead test. Eye movements were recorded using a video eye tracker and stimuli were presented with a large format projection system. Using methods described previously (Renninger, et. al. JOV 2007) we compute the information gained by the patient as they study a novel shape silhouette. This computation takes into account the size and location of the scotoma, as measured by microperimetry with a scanning laser ophthalmoscope. The efficiency of the eye movement strategy is taken as the ratio of information gained divided by the maximum gain possible, averaged over fixations. Results support the hypothesis that reading performance is correlated with the efficiency of the eye movement pattern.
Pacific Vision Foundation; NIH R01 EY018004