Abstract
Purpose :
Novel approaches to assess both functional and anatomic changes within the central 3 degrees macula in patients undergoing anti-complement treatment for geographic atrophy (GA) are needed. In the present study, results assessing the utility of an approach to measure photopic retinal sensitivities using small spot sizes arranged in a dense grid in the central macula (focal microperimetry) are presented.
Methods :
In this prospective study, 17 eyes from 13 subjects (7 males and 6 females, age ≥ 65 years) with evidence of peri-foveal geography atrophy (GA) as determined by optical coherence tomography (OCT) and fundus auto-fluorescence (FAF) and best-corrected visual acuity (BCVA) equal to or better than 20/80 were included. Focal microperimetry was performed using a Nidek MP-3 type S microperimeter, a test stimuli pattern of 45 points centered on the fovea, with spacing of 0.5 degree and a stimulus size of Goldmann II (0.21 degree diameter). To assess test-retest repeatability, 2 visits up to 60 days apart were performed. Repeatability was determined using Bland Altman analysis, intraclass correlation (ICC) and coefficient of repeatability (CoR). Various measures of subject performance were also collected. Structure-function correlation will be analyzed using OCT scans acquired on Heidelberg Spectralis HighRes OCT.
Results :
Subject performance metrics demonstrated that the mean (+/- SD) of total time required per eye testing was 4.33 (+/- 0.76) minutes with an average fixation within the 2 degree diameter ranging from 88.4 - 90.3 % and a BCEA @68.2% of 1.3 degree sq. Mean retinal sensitivities for the two tests were 13.9 dB with an ICC of 0.98 and CoR (95% CI) of 2.25 (1.2 - 3.3) dB, confirmed by Bland-Altman plots demonstrating a LoA between -1.7 and 2.8 dB.
Conclusions :
The use of photopic focal microperimetry within the central 3 degrees appears to be a reliable approach to measure central visual function in patients with GA. The low time to perform the test and short learning curve are strengths in addition to the adequate test-retest variability. These data support the test’s ability to detect important differences in patients undergoing anti-compliment therapies for GA. Correlations to various anatomic structures will also be presented.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.