Novel 3 D Computerized Threshold Amsler Grid Test

Purpose: To introduce a novel 3D computerized threshold Amsler grid test, developed by Fink and Sadun, that allows for a novel characterization of the structure of visual field defects in three dimensions (see http://www.wfbabcom5.com/wf335.htm). Methods: With one eye covered, patients are placed in front of a computer monitor displaying an Amsler grid. While focusing on a varying central fixation marker, the patients trace the areas, on a touch sensitive screen overlaying the displayed grid, that are missing from their field of vision, with their finger. The procedure is repeated with varying degrees of grid contrast. The results are recorded and later displayed as topographical contour rings, in a 3D depiction of the central hill-of-vision. Results: Several clinical pilot studies have been conducted at the Doheny Eye Institute and over 200 patients have been examined so far. Conditions such as optic neuritis, anterior ischemic optic neuropathy, age-related macular degeneration, glaucoma, and ocular hypertension have been examined with the 3D visual field test. The tested visual field is limited to the central 20 to 25 degrees (depending on the computer monitor size). The physiological blind spot cannot be detected with this test due to the " fill-in phenomenon ". Conclusions: The 3D computerized threshold Amsler grid test is an innovative and fast (4-5 min. per eye) visual field test. It provides several novel features, including: a) additional information through immediate 3D rather than 2D depiction of scotomas, such as location, extent, slope, depth, and shape; b) simple test-setup; c) good patient compliance. In light of results from pilot studies, the 3D visual field test appears to have the potential for the early detection and monitoring of various diseases, in particular glaucoma and macular degeneration. 3 1. Introduction Visual field testing (perimetry) has always been an important part of an ophthalmological evaluation. In 1947 Amsler [1, 2] introduced a suprathreshold grid for evaluating the central ten degrees of the visual field. The high contrast of the standard Amsler test may fail to detect subtle field defects, such as relative scotomas.