The afferent pupillary defect in asymmetric glaucoma.

The OCTOPUS 2000 perimeter and a central 30 degrees program were used to study consecutively 27 patients with glaucoma who had either a relative afferent pupillary defect (APD) or asymmetric optic nerve cupping without an APD. The mean difference in visual field sensitivity between fellow eyes was 48.2% (range, 13% to 93%) for the APD group and 5.5% (range, 0% to 9.0%) for the non-APD group. The mean difference in cup-disc ratio was 0.43 (range, 0.2 to 0.6) for the APD group and 0.24 (range, 0.2 to 0.3) for the non-APD group. The APD depth was quantitated with neutral density filters and correlated with visual field asymmetry but not with cup-disc ratio asymmetry. There was no overlap between the APD and non-APD groups in the amount of visual field asymmetry: Every patient with a sensitivity difference of 13% or greater had an APD. The presence of an APD indicates that a threshold of asymmetric optic nerve damage has been exceeded. With automated perimetry, this threshold can be quantitated and may improve the assessment of patients with glaucoma.