Quantitative evaluation of manual kinetic perimetry using computer simulation

Manual kinetic perimetry is a common technique for detection and evaluation of visual field loss in glaucoma and other ophthalmic diseases. Previous investigations have examined the accuracy and reproducibility of kinetic perimetry, but have disagreed as to the source of variability in the test results.(1,2) In these studies, patient response characteristics could not be specified. The present study examined the effects of controlled patient factors on performance of manual kinetic perimetry. Three technicians each conducted thirty-six kinetic perimetry examinations on normal and abnormal visual fields with varying degrees of response errors and sensitivity fluctuations, using the KRAKEN computer simulation program.(3) Performance measures included elapsed time, number of plotted isopter and scotoma boundaries, time per boundary, mean error over the entire field, and mean local error within sectors. In addition, perimetrists judged the cooperation and reliability of the simulated patient on a five-point scale. Measures of accuracy yielded significant differences in location within the visual field: central vs peripheral and superior vs inferior. Measures of efficiency yielded significant effects of patient cooperation, normal vs abnormal visual fields, and technician's level of experience. Patient cooperation, as judged, agreed with simulated reliability. This approach appears to have promise as a training procedure for manual kinetic perimetry.