Abstract
Purpose :
To investigate sensitive outcome measures based exclusively on abnormal points in microperimetry testing of eyes with intermediate age-related macular degeneration (iAMD)
Methods :
25 eyes of 25 subjects with iAMD had undergone 2 successive tests of mesopic microperimetry with the Macular Integrity Assessment Microperimeter (MAIA), using a custom grid of 33 points spanning the central 14 degrees of the macula. Each point was defined as abnormal if its threshold sensitivity was lower than 1.65 standard deviations (SD) (5%) or 2 SD (2.5%) than the expected threshold in healthy eyes according to the MAIA internal database. We analyzed the number of abnormal points in each test, their mean sensitivity and deviation from normal values, and compared the repeatability of these measures with those of all the points in the grid.
Results :
Among the 25 eyes there were 11.8 ± 9 and 8.4 ± 8.2 abnormal points at <5% and <2.5%, with mean deviation of thresholds from normal -4.9 ± 1.2 dB and -5.8 ± 1.5 dB, respectively. These deviations were greater, and their SD smaller, compared with the mean deviation of all points in the microperimetry grid which was -2.3 ± 2.0 dB. The number of eyes with at least 5 abnormal points was 19 (76%) and 14 (56%) using the two criteria. The 95% limits of agreement for average threshold between the 2 successive tests were smaller when only abnormal points were included compared with the complete grid, 3.2 vs 4.2 dB, implying better repetability.
Conclusions :
We propose a framework for the construction of an outcome measure for clinical trials of visual function improvement in iAMD that consists only of microperimetry points that are abnormal at baseline. Despite limiting the analysis to a particular subset of points, most subjects in this iAMD cohort could be enrolled. Advantages include a greater average deviation allowing more ample opportunity for observable effect of any intervention, a more homogenous dataset, and excellent test-retest variability.
This is a 2021 ARVO Annual Meeting abstract.