Test could aid detection of AMD

November 2, 2007

According to a Canadian study, computer-based methods for evaluating the eye's ability to distinguish object details and shape in patients with age-related macular degeneration (AMD) could provide a more accurate assessment of the effectiveness of eye surgery and vision rehabilitation.

According to a Canadian study, computer-based methods for evaluating the eye's ability to distinguish object details and shape in patients with age-related macular degeneration (AMD) could provide a more accurate assessment of the effectiveness of eye surgery and vision rehabilitation.

Authors of the study incorporated four known features to improve visual acuity in their computer-based method: high contrast; white optotypes (symbols, letters, or numbers used in vision testing) on a black background to reduce intraocular scatter; proportional layout to reduce the effect of crowding; and multiple optotypes to minimize the effects of fixation instability and to maximize the likelihood of optotype detection.

After experimenting authors concluded that a multiple-optotype, reversed-polarity test is most effective in estimating a patient's optimal visual acuity at baseline before vision rehabilitation interventions or surgery.

"People with AMD rarely read or view things under optimal conditions, so this is not a test of how well they see in daily life," said study author, Esther G. González "This test is designed to give vision rehabilitation practitioners a measure of the best visual acuity a person is capable of and in this sense it could be a useful tool for assessing rehabilitation progress."