Retinal Structure and Functional Correlation in Subjects with Dry Age-Related Macular Degeneration Using Spectral Domain Optical Coherence Tomography and Scotopic Microperimetry

Abstract

Purpose : To evaluate the relationship between structural and functional parameters measured using spectral domain optical coherence tomography (SD-OCT) and scotopic microperimetry (MP-1S) in subjects with dry age-related macular degeneration (AMD).

Methods : Twenty-four eyes from 23 subjects with dry AMD were included in this IRB-approved prospective cross-sectional study from the Retina Foundation of the Southwest. All subjects underwent SD-OCT and MP-1S testing. Retinal sensitivity was measured using a Nidek MP-1S with 2 neutral density filters using a macular grid of 32 stimuli. SD-OCT was performed using Spectralis HRA+OCT (Heidelberg Engineering Inc., Germany). Thickness measurements were generated after two independent reading center-certified graders manually segmented the individual retinal layers: outer nuclear layer (ONL), inner segments (IS), outer segments (OS), retinal pigment epithelium (RPE), and pigment epithelium detachment (PED) in all 31 B-scans of each study eye using 3D OCTOR software. Retinal sensitivity maps and thickness maps generated for each layer by SD-OCT were registered and the mean and maximum thickness values of each retinal layer were extracted for circles with radii of 100, 200, 300, 400, and 500 microns from the center of each MP retinal sensitivity locus. Correlation between local retinal sensitivity and corresponding layer thickness was analyzed using bivariate Pearson correlations (SPSS ver. 18.0).

Results : The mean retinal sensitivity was 11.29 ± 7.50 dB. The local retinal sensitivity was significantly but weakly correlated with mean and maximum retinal thickness measurements of each retinal layer: total retina (r = 0.26; p <0.001), ONL (r = 0.23; p <0.001), IS (r = 0.25; p <0.001), OS (r = 0.33; p <0.001), RPE (r = 0.24; p <0.001), PED (r = 0.04; p = 0.19) in a 100 micron radius circle. Similar correlations were observed for different radii (as shown in Table 1).

Conclusions : Scotopic retinal sensitivity appears to correlate weakly with retinal layer thickness in subjects with dry AMD. Other factors which predict visual function in these patients need further elucidation.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.