Spatial Cluster Patterns of Retinal Sensitivity Loss in Intermediate Age-Related Macular Degeneration Features

PURPOSE: To examine spatial patterns of retinal sensitivity loss in the three key features of intermediate age-related macular degeneration (iAMD). METHODS: One-hundred individuals (53 iAMD, 47 normal) underwent 10-2 mesopic microperimetry testing in one eye. Pointwise sensitivities (dB) were corrected for age, sex, iAMD status, and co-presence of co-localized key iAMD features: drusen load, pigmentary abnormalities, and reticular pseudodrusen (RPD). Clusters (labeled by ranks of magnitude C(−2), C(−1), C(0)) were derived from pointwise sensitivities and then assessed by quadrants and eccentricity/rings. RESULTS: Two clusters of decreased sensitivities were evident in iAMD versus normal: C(−2), −1.67 dB (95% CI (confidence intervals), −2.36 to −0.98; P < 0.0001); C(−1), −0.93 dB (95% CI, −1.5 to −0.36; P < 0.01). One cluster of decreased sensitivity was independently associated each with increased drusen load (13.57 µm increase per −1 dB; P < 0.0001), pigmentary abnormalities (C(−1): −2.23 dB; 95% CI, −3.36 to −1.1; P < 0.01), and RPD (C(−1): −1.07 dB; 95% CI, −2 to −0.14; P < 0.01). Sensitivity loss in iAMD was biased toward the superior and central macula (P = 0.16 to <0.0001), aligning with structural distributions of features. However, sensitivity loss associated with drusen load also extended to the peripheral macula (P < 0.0001) with paracentral sparing, which was discordant with the central distribution of drusen. CONCLUSIONS: Drusen load, pigmentary abnormalities, and RPD are associated with patterns of retinal sensitivity loss commonly demonstrating superior and central bias. Results highlighted that a clinical focus on these three key iAMD features using structural measures alone does not capture the complex, spatial extent of vision-related functional impairment in iAMD. TRANSLATIONAL RELEVANCE: Defining the spatial patterns of retinal sensitivity loss in iAMD can facilitate a targeted visual field protocol for iAMD assessment.