A Test of a Model of Glaucomatous Damage of the Macula With High-Density Perimetry: Implications for the Locations of Visual Field Test Points

Abstract

To use high-density perimetry to test a model of local glaucomatous damage to the macula (central visual field [VF]) and to assess the optimal placement of stimuli used to detect this damage. Thirty-one eyes of 31 patients showing glaucomatous arcuate damage within the upper hemifield of the central 10° were tested with a customized VF with double the density of the 10-2 (2° grid) test. Individual plots of total deviation (TD) values were generated. A model, which predicts a "vulnerable macular region" (VMR) and a "less vulnerable macular region" (LVMR), was compared with the TD values without (standard model) and with (aligned model) scaling and rotating to align it with the patient's fovea-to-disc axis. Computer simulations assessed alternative VF locations for adding two points to the 6° grid pattern (e.g., 24-2 VF) typically used in the clinic. There were significantly more abnormal points in the VMR than in the LVMR. However, the aligned model did no better than the standard model in describing the data. The optimal locations for adding two points to the 24-2 (6° grid) test were (-1°, 5°) and (1°, 5°), both within the VMR. The model describes the region of the superior VF vulnerable to arcuate damage. The model can be used to determine the optimal locations for adding test points to the commonly used VF test pattern (24-2). It does not seem necessary to adjust the location of VF test points based upon interindividual differences in the fovea-to-disc axis.