A shape statistic for visual field evaluation: Utility in minor optic neuropathy

Minor deviations from the normal threshold surface are difficult to identify in static perimetry. Numerical assessment of surface shape is a possible remedy. An easily calculated statistic that depends on an extended isopter concept is presented. It is capable of detecting small aberrations from normal. Sensitivity was superior to that of pattern standard deviation in subjects with resolved optic neuritis. Specificity was estimated at 95%.