Abstract
Abstract: :
Purpose: To compare the original Amsler grid with white lines on black background developed by Mark Amsler in 1947, exemplified by the Yannuzzi card (YC), to the modified grid (MG) with black lines and white background used in the eye clinics on a daily basis and given to patients for home monitoring of central visual changes in macular diseases. Methods: Patients with a variety of macular diseases (129 eyes: 37 with cystoid macular edema, 54 with clinically significant diabetic macular edema, 31 with age-related macular degeneration, 4 with central serous retinopathy, and 3 with epiretinal membranes) were tested with both grids and changes were recorded according to original questions designed by Amsler. Macular pathology representing the basis of the central visual distortion was confirmed by slitlamp biomicroscopic examination, fluorescein angiography, and optical coherence tomography if needed. Results: When visual acuity was better than 20/50, central visual field abnormalities were detected with either grid. Patients in this subgroup preferred the MG to the YC to describe central visual distortion, which correlated better with the corresponding macular pathologic changes (84% versus 16% respectively). At visual acuity of 20/50 or worse, central visual distortions corresponding to the macular pathology were more detectable on the YC than the MG (89% versus 11% respectively). When visual acuity dropped to below 20/200, no changes could be detected on either grid, in spite of the presence of macular pathology. Preference of the YC to the MG as the visual acuity drops can be explained by the double opponent theory, the intensity differential theory, and the theory of major cone stimulation. Conclusion: The YC and the MG are both useful in detecting central visual changes correlating to pathologic changes in macular diseases when visual acuity is better than 20/200. The MG is preferred with visual acuity better than 20/50 while the YC is preferred with lower levels of visual acuity but better than 20/200. It is advisable to test patients with the appropriate grid according to the level of their visual acuity and more importantly to choose the correct grid for the patient to take home for early detection of changes in macular diseases.
Keywords: 554 retina • 460 macula/fovea • 368 contrast sensitivity