Establishing Fully-Automated Fundus-Controlled Dark Adaptometry: A Validation and Retest-Reliability Study

ABSTRACT Purpose To establish and validate a novel fundus-controlled dark-adaptometry method. Methods We developed a custom dark-adaptometry software for the S-MAIA device using the open perimetry interface. In the validation-substudy, participants underwent dark-adaptometry testing with a comparator device (MonCvONE, 59% rhodopsin bleach, cyan and red stimuli centered at 2°, 4°, and 6° eccentricity). Following a brief break (approx. 5 min), the participants were bleached again and underwent dark-adaptometry testing with the S-MAIA device (same loci). In the retest reliability-substudy, participants were tested twice with the S-MAIA device (same loci as above). Nonlinear curve fitting was applied to extract dark-adaptation curve parameters. Validity and repeatability were summarized in terms of the mean bias and 95% limits of agreement (LoAs). Results In the validation-substudy (N=20 participants, median age [IQR] 31.5 years [25.8, 62.0]), measures of rod-mediated dark-adaptation showed little to no between method differences for the cone-rod-break-time (bias [95% CI] of +0.09 min [-0.5, 0.67]), rod-intercept-time (+0.42 min [-0.51, 1.35]), and S2 slope (-0.03 LogUnits/min [-0.04, -0.02]). In the retest reliability-substudy (N=10 participants, 32.0 years [27.0, 57.5]), the corresponding LoAs were (cone-rod-break-time) -3.01 to 2.02 min, (rod-intercept-time) -3.95 to 2.94min, and (S2 slope) -0.09 to 0.07 LogUnits/min. The LoAs for the steady-state cone and rod thresholds were -0.27 to 0.31 LogUnits and -0.32 to 0.27 LogUnits. Conclusions The devised fundus-controlled dark-adaptometry method yields valid and reliable results. Fundus-controlled dark-adaptometry solves the critical need for localized testing of the visual cycle in eyes with unstable fixation (e.g., in the setting of subretinal gene therapy).