Novel 3D computer-automated threshold Amsler grid visual field testing of scotomas in patients with glaucoma.

PURPOSE: Three-dimensional (3D) computer-automated threshold Amsler grid testing was used to identify and characterize scotomas typical of glaucoma. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Early detection of glaucoma by means of a novel 3D computer-automated visual field test.

PURPOSE: A recently devised 3D computer-automated threshold Amsler grid test was used to identify early and distinctive defects in people with suspected glaucoma. Further, the location, shape and depth of these field defects were characterised. Finally, the visual fields were compared with those obtained by standard automated perimetry. PATIENTS AND METHODS: Glaucoma suspects were defined as those having elevated intraocular pressure (>21 mm Hg) or cup-to-disc ratio of >0.5. 33 patients and 66 eyes with risk factors for glaucoma were examined. 15 patients and 23 eyes with no risk factors were tested as controls. The recently developed 3D computer-automated threshold Amsler grid test was used. The test exhibits a grid on a computer screen at a preselected greyscale and angular resolution, and allows patients to trace those areas on the grid that are missing in their visual field using a touch screen. The 5-minute test required that the 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 characterised by the location, shape and depth of the scotomas. The exam was repeated three times per eye. The results were compared to Humphrey visual field tests (ie, achromatic standard or SITA standard 30-2 or 24-2). RESULTS: In this pilot study 79% of the eyes tested in the glaucoma-suspect group repeatedly demonstrated visual field loss with the 3D perimetry. The 3D depictions of visual field loss associated with these risk factors were all characteristic of or compatible with glaucoma. 71% of the eyes demonstrated arcuate defects or a nasal step. Constricted visual fields were shown in 29% of the eyes. No visual field changes were detected in the control group. CONCLUSIONS: The 3D computer-automated threshold Amsler grid test may demonstrate visual field abnormalities characteristic of glaucoma in glaucoma suspects with normal achromatic Humphrey visual field testing. This test may be used as a screening tool for the early detection of glaucoma.

Scotomas of age-related macular degeneration detected and characterized by means of a novel three-dimensional computer-automated visual field test.

PURPOSE: We used the recently devised three-dimensional computer-based threshold Amsler grid test to acquire and identify typical patterns of visual field defects (scotomas) caused by age-related macular degeneration (AMD). METHODS: Patients with AMD traced on a computer touch screen the borders of those areas on an Amsler grid that were missing from their field of vision. Scotomas were repeatedly outlined and recorded at different grid contrast levels. The resulting three-dimensional "hole" in the central 25 degrees of the visual field was further characterized by its slope, location, shape, and depth. The results were compared with fundus photographs and fluorescein angiograms. RESULTS: Twenty-five patients and 41 eyes were examined. The three-dimensional depictions consistently demonstrated central scotomas with "scallop"-shaped borders and steplike patterns, with either steep slopes or a combination of steep and shallow slopes. The steep slopes corresponded to nonexudative AMD, while the shallow slopes indicated exudative AMD. CONCLUSION: The three-dimensional computer-automated threshold Amsler grid test may demonstrate characteristic scotoma patterns in patients with AMD that conform to the respective fluorescein angiograms. The test shows promise as an effective tool in accurately evaluating, characterizing, and monitoring scotomas in patients with AMD. It may have the potential as a screening tool for the early diagnosis of AMD.