Repeatability of Foveal Sensitivity Measured Using Adaptive Optics Microperimetry

To assess the within and between-session repeatability of foveal sensitivity measurements using adaptive optics (AO) microperimetry.

Five normal-sighted participants underwent AO microperimetry testing (550-nm circular stimulus) at the preferred retinal locus across two sessions (2 months ± 2 weeks). Two psychophysical paradigms were used: quick estimation of threshold (QUEST) and method of constant stimuli (MOCS). Each paradigm employed both 1.05-arcmin2 and 30.4-arcmin2 stimulus sizes; stimuli were not stabilized in real time. Trial-by-trial responses were fit with a logistic psychometric function to obtain thresholds at a criterion of 78% seen. Thresholds were converted to sensitivity. Statistical comparisons were performed using paired-sample t-tests.

Sensitivities measured from QUEST and MOCS procedures were not significantly different (QUEST: 1.05 arcmin2, P = 0.36 for session 1 and P = 0.41 for session 2; MOCS: 30.4 arcmin2, P = 0.14 for session 1 and P = 0.12 for session 2). Data were thus combined across paradigms for tests of repeatability. Sensitivities for data split into two groups within session 1 and separately within session 2 were not significantly different (QUEST: 1.05 arcmin2, P = 0.34 for session 1 and P = 0.51 for session 2; MOCS: 30.4 arcmin2, P = 0.31 for session 1 and P = 0.27 for session 2). Overall, sensitivities across the two sessions were not significantly different (QUEST: 1.05 arcmin2, P = 0.06; MOCS: 30.4 arcmin2, P = 0.81). The coefficients of repeatability across sessions were 1.5 decibels (dB) and 0.4 dB for 1.05 arcmin2 and 30.4 arcmin2, respectively.

Sensitivity measurements from AO microperimetry were repeatable within and across sessions.

Results of the present study will guide future longitudinal studies of disease progression in detecting sensitivity changes using AO microperimetry.