Abstract
Purpose: :
This is an IRB approved prospective consecutive study of 44 healthy individuals that were tested with the Spectral Domain OCT/Microperimeter (OPKO SLO/OCT) after informed consent. Microperimetry was performed on each eye using a circular grid of 28 test spots centered on the fovea using a 4-2 threshold strategy. The average threshold sensitivity was compared between the two subject groups. The purpose of this study was to evaluate and compare the effect of fatigue on the second eye when two eyes are measured in succession.
Methods: :
44 healthy individuals with corrected visual acuities of 20/25 or better and normal exams were selected for microperimetry. The first group of 22 subjects underwent microperimetry testing in both eyes consecutively without interruption. The second group of 22 subjects were given a 15 minute rest period between testing sessions. Both groups were randomized according to which eye was tested first. The mean threshold retinal sensitivity was determined for each eye, and the two groups were compared for the difference in average sensitivity between the two eyes.
Results: :
The first group that had no resting period between testing sessions had 16 of 22 (73%) that showed a decrease in retinal sensitivity between the first and second eye tested. The remainder (6 of 22) showed an increase in average retinal sensitivity. The second group of subjects that had a 15 minute resting period between sessions had 11 of 22 (50%) with decreased sensitivity in the second eye tested. The remainder in this group (11 of 22) showed an increase in average retinal sensitivity.
Conclusions: :
If there is no fatigue effect from testing both eyes in immediate succession, one would expect to find an equal proportion of subjects that had an increase versus a decrease in retinal sensitivity of the second eye tested. This was the case for the second group of subjects that were given a 15 minute rest period between testing the first eye and the fellow eye. There was a statistically significant proportion of subjects in the first group with no resting period that had a decrease in average retinal sensitivity between the first eye tested and the second eye tested. This demonstrates a statistically significant fatigue effect in this group. Based on these results, a resting period is recommended for optimal retinal sensitivity results with microperimetry.
Keywords: visual fields • retina