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April 1986

Threshold Amsler Grid TestingCross-Polarizing Lenses Enhance Yield

Author Affiliations

From the Departments of Ophthalmology and Neurology, Tulane University School of Medicine, New Orleans (Dr Wall) and the University of Southern California School of Medicine, Los Angeles (Dr Sadun).

Arch Ophthalmol. 1986;104(4):520-523. doi:10.1001/archopht.1986.01050160076015

• The Amsler grid is a commonly used test for evaluation of the 10° of visual field surrounding fixation. The Amsler grid is a suprathreshold stimulus and thus may not detect relative scotomas. Therefore, we had ten patients with optic neuropathies view the grid through cross-polarizing filters that created low luminance conditions in which the grid was barely perceptible. The patients were also surveyed with a 2-m tangent screen protocol and threshold automated perimetry. The threshold Amsler grid technique increased both the number of defects found and the total area of these defects by approximately a factor of 5. Two thirds of the defects found were confirmed by one of the other screening techniques. Threshold Amsler grid testing is a rapid, inexpensive, and sensitive technique for the evaluation of the central 10° of the visual field.