Novel 3D Computer-Automated Threshold Amsler Grid Visual Field Testing of Scotomas in Patients with Glaucoma

Abstract

Three-dimensional (3D) computer-automated threshold Amsler grid testing was used to identify and characterize scotomas typical of glaucoma. The 3D test exhibits a grid on a computer screen at a preselected grayscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. Eleven eyes in patients with an established diagnosis of glaucoma were examined according to the above protocol. A total of 23 eyes from normal subjects were used as controls. The 5-minute test required that patients repeatedly outline scotomas on a touch screen with varied displays of contrast while maintaining their gaze on a central fixation marker. A 3D depiction of the visual field defects was then obtained that was further characterized by the location, shape, extent, depth, and slope of the scotomas. In this pilot study, the 3D depiction of visual field loss demonstrated paracentral, superior and inferior altitudinal, and nasal step defects consistent with glaucomatous damage. The 3D depiction showed a shape, extent, depth, and slope that are consistent with the severity of damage. The 3D test identified and characterized scotomas typical of glaucoma. The test provides several advantages over conventional perimetry including additional information through 3D depiction of scotomas with the addition of contrast sensitivity and a higher angular/spatial resolution. Improved patient compliance and reliability through shorter testing time and potential interactive accessibility and distribution over the Internet further characterize the test.