Reading Analysis in Ophthalmologic Patients

Reading is a complex function. It requires a proper retinal image that is received by the brain. There it is analyzed for letter and word recognition and then the semantics is detected. Reading speed slows down when letters are blurred, or do not have enough contrast or luminance or when binocular fusion is hampered. Hence, it is obvious that reading ability is reduced in patients with various ocular diseases. Especially, pathologies effecting the posterior pole (central and paracentral vision) might impair reading parameters significantly. Recently, the Eyetracker Eyelink 1000 (SR Research Ltd, Canada) became available. It´s application was described previously. Briefly, a high-speed infrared camera detects the position of eye (pupil and corneal reflex) and in turn the direction of gaze 500 times per second. During the calibration process the position can be linked to the position on a screen where, for instance, a text or a fixation target can be projected. Direction of gaze is recorded during the reading process and the gathered data are analyzed. Fixation ability was assessed using Eyelink 1000 in patients with age-related macular degeneration. It was shown that fixation is related to visual function. The worse eye showed reduced fixation ability which is improved during binocular fixation. This study investigates reading parameters in patients with various ocular diseases.