Psychophysical comparison of four automated perimeters.

It is not unusual for a doctor to detect a field loss on the office perimeter and refer the patient to a setting where a different perimeter is used. In such cases, fields are often repeated because of a lack of "comparability." In this study, we compared the "hill of vision" produced by four major types of perimeters. When possible, we explored alternate user-defined stimulus configurations in order to determine if a rough equivalence could be obtained among the various instruments. Background intensity and target size accounted for many of the differences found in the data. Target color, stimulus duration, and noise had relatively little effect. Despite our stimulus manipulations, subtle (but perhaps significant) differences in the hills of vision remained.