Functional Microperimetric Correlates of OCT Structural Features in Intermediate Age-related Macular Degeneration

Abstract

Purpose : Structure-function correlation studies are essential to better understand age-related macular degeneration (AMD) disease pathophysiology and to define surrogate endpoints for early intervention clinical trials. The purpose of this study is to characterize the microperimetric correlates of OCT structural features in intermediate AMD.

Methods : OCT volumes (20°x20°, ART 5, 97 lines; Spectralis HRA+OCT, Heidelberg Engineering, Germany) and photopic microperimetry (MP-3 type S; Nidek Co.Ltd., Japan) were prospectively obtained from 20 eyes with evidence of intermediate AMD on fundus examination at the Doheny-Eye Centers UCLA from January 2023 to June 2023. The microperimetry grid consisted of a 20°x20° macular pattern of 33 stimuli (Goldman III, 4-2 fast) centered on the fovea. A pointwise sensitivity (PWS) analysis was carried out to correlate the mean photopic sensitivity (dB) at each microperimetric stimulus with the corresponding OCT structural feature. Linear mixed effects models were employed, taking into account the multilevel/hierarchical nature of the data structure to assess the relationship between PWS and OCT structural features. For each OCT structural feature, we report the mean sensitivity (MS). An extension of the Heyex Spectralis Heidelberg review software was used to co-localize the microperimetry stimulus to the OCT B-scan at that location.

Results : 18 eyes of 15 subjects were eligible for the analysis (mean age 83.16 ± 7.08; F 66.6 %). 14 subtypes of OCT structural features were detected (reference “none” = absence of AMD structural features on OCT; Table 1). 552 PWS were assessed from a total of 594 (41 were dropped for being located outside the OCT pattern). The least mean PWS was recorded corresponding to incomplete retinal pigment epithelial and outer retina atrophy, followed by acquired vitelliform lesion, external limiting membrane attenuation/disruption, intraretinal hyperreflective foci, and presence of multiple photoreceptors degeneration signs, representing evidence of more than one PRDS, suggesting a more advanced stage of the disease. (Table 2)

Conclusions : The study of the functional profile of each OCT structural feature in eyes with intermediate AMD exploring a PWS analysis provides new insights into the pathophysiology and evolution of AMD. This information will be essential for defining surrogate biomarkers.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.