Geographic Atrophy Structure-Function Relationships Based on Loss of OCT Outer Retinal Bands and Fundus...

To examine the association between the loss of the OCT outer retinal bands and deep visual sensitivity losses quantified by defect-mapping microperimetry (DMP).

Cross-sectional study.

Fifty individuals with geographic atrophy (GA) secondary to age-related macular degeneration.

All participants underwent DMP testing-a strategy optimized to quantify the spatial extent of deep visual sensitivity losses through single presentations of 10 decibel stimuli-with 208 locations sampled within the central 8° radius region. Participants also underwent OCT and fundus autofluorescence (FAF) imaging. OCT scans were automatically segmented to detect regions of retinal pigment epithelium (RPE), ellipsoid zone (EZ), and external limiting membrane (ELM) loss, and FAF images were manually annotated for GA. The extent of these parameters in the central 8° radius region where DMP testing was performed, and at each individual test location, was derived through image coregistration for evaluating structure-function associations.

Global structure-function correlation between the proportion of locations missed on DMP testing and the extent of loss of the structural parameters based on Spearman rank correlation coefficient (ρ), and spatial agreement between the presence of structural changes and missed stimuli on DMP testing at individual test locations based on the Dice similarity coefficient (DSC).

There were strong global structure-function correlations based on loss of the OCT outer retinal bands (ρ = 0.85-0.86), similar to what was seen with FAF-defined GA (ρ = 0.89; P ≥ 0.326). However, the spatial agreement between OCT-defined EZ and ELM loss with missed stimuli on DMP testing (DSC = 0.64 for both) was higher than that seen with RPE loss (DSC = 0.60) and FAF-defined GA (DSC = 0.62; P = 0.008 for both), but the structure-function spatial agreement was similar between RPE loss and FAF-defined GA (P = 0.152).

Spatial agreement with pointwise deep visual sensitivity losses was comparable based on OCT-defined RPE loss and FAF-defined GA, but higher based on EZ and ELM loss. These findings confirm the expected functional relevance of these automatically derived OCT-defined parameters and support their utility as tools for monitoring GA progression.

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.