Reliability of simultaneous visual field testing

Abstract

Objective: To test for differences in reliability and performance between traditional, isolated perimetry and simultaneous testing with 2 patients in the same room.

Design: Comparative case series.

Participants: A total of 471 eyes of 261 subjects.

Methods: Consecutive patients undergoing Humphrey visual field (VF) testing in the Kellogg Eye Center glaucoma clinic were screened. Patients who underwent VF testing with another patient in the same room ("double field") during the screening interval were included as subjects if a comparison isolated VF from the same patient ("single field") was obtainable from the clinic's records. An individual subject's performance and reliability on his/her double and single fields were compared using a paired t test. In addition, the double fields were stratified by technician-to-patient ratio, and their VF indices were compared using an independent 2-sample t test.

Main outcome measures: False negatives, false positives, fixation losses, mean deviation, pattern standard deviation, VF index, VF duration, and technician-to-patient ratio.

Results: No significant differences between single and double fields were found in the reliability or performance parameters. Test duration was longer in double fields than in single fields (6.1 vs. 5.9 minutes, P < 0.001). There were no significant differences found in reliability or performance indices when the double-field data were stratified by technician-to-patient ratio (1:2 vs. 2:2).

Conclusions: There is no decrement in VF performance or reliability when patients undergo simultaneous testing with another patient in the same room. Busy clinical practices may be able to minimize costs and maximize efficiency by having 1 technician simultaneously supervise more than 1 test-taker in the same space.