Abstract
Purpose: :
To determine if patient performance on automated static perimetry is affected by the presence of more than one test taker in the same room or by the technician-to-patient ratio.
Methods: :
Consecutive patients undergoing Humphrey visual field (HVF) testing in the Kellogg Eye Center Glaucoma clinic from October 2008 to April 2009 were screened. A "double field" was defined as a HVF that occurred with at least one minute of overlap with another test-taker in the same room undergoing simultaneous HVF testing. A "single field" was defined as a HVF from the same patient’s same eye, performed in a room without another patient present using the same testing protocol within two years of the double field. All double fields from the screening interval were included as long as a comparison single field was available. If more than one eligible single field was present, the chronologically proximal HVF was selected for comparison. All pertinent data from each HVF were recorded: age, visual acuity, HVF duration, testing protocol, fixation losses (FL), false positives (FP), false negatives (FN), glaucoma hemifield test (GHT) score, visual field index (VFI), mean deviation (MD), pattern standard deviation (PSD), and the technician-to-patient ratio. Individuals’ single and double visual field performance and reliability were compared using a paired t-test. The double fields were stratified by technician-to-patient ratio and their HVF parameters were compared using an independent t-test.
Results: :
Double fields from 471 eyes (261 subjects) were collected. No significant differences between single and double fields were found in the reliability (FL, FP, FN) or performance (VFI, MD, PSD) indices. Test duration was longer in double fields than single fields (6.1±1.5 vs 5.9±1.5 minutes, p=0.0006). 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: :
HVF testing performed by two glaucoma patients in the same room is not associated with any decrement in reliability or performance when compared to HVF testing performed by each patient singly. These results hold true regardless of the technician-to-patient ratio in a double field. With today’s emphasis on cost containment and maximizing clinical efficiency, these findings are relevant to a large number of busy ophthalmology clinics.
Keywords: visual fields • clinical (human) or epidemiologic studies: systems/equipment/techniques • perimetry