Accuracy of kinetic perimetry assessment with the Humphrey 850; an exploratory comparative study.

The Humphrey perimeter's aspheric bowl introduces a ceiling effect for measurements in the superior and inferior visual field at approximately 40 and 50 degrees respectively. This results in potential diagnostic accuracy issues when measuring uniocular rotations, fields of binocular single and visual field boundaries in conditions that specifically impair superior and/or inferior ocular motility (e.g., thyroid eye disease) or visual fields (e.g., chiasmal compression).