In vivo cone-photoreceptor density comparison between eyes with subretinal drusenoid deposits and healthy eyes using high magnification imaging

Abstract

Purpose: To compare photoreceptor density automated quantification in eyes with subretinal drusenoid deposits (SDD) and healthy controls using Heidelberg Spectralis High Magnification Module (HMM) imaging.

Methods: Twelve eyes of 6 patients with intermediate AMD, presenting with SDD were included, as well as twelve eyes of healthy controls. Individual dot SDD within the central 30° retina were examined with infrared confocal laser ophthalmoscopy, HMM, and spectral-domain optical coherence tomography (SD-OCT). Photoreceptor density analysis was performed on the best-quality image using the ImageJ Foci Picker plugin, after the removal of SDD from the HMM image. Correlations were made between the HMM quantified photoreceptor density, SD-OCT characteristics, stage, and number of SDD.

Results: Mean age was 75.17 ± 2.51 years in the SDD group (3 males, 3 females) versus 73.17 ± 3.15 years in the healthy control group (p = 0.2). Defects in the overlying ellipsoid zone were present on SD-OCT in 8/12 (66.66%) eyes. The mean ± standard deviation foci detected (i.e., cone photoreceptors) was 7123.75 ± 3683.32 foci/mm² in the SDD group versus 13,253 ± 3331.00 foci/mm² in the healthy control group (p = 0.0003). The number of SDD was associated with a reduction in foci density, p = 0.0055, r = - 0.7622.

Conclusion: The decreased cone density in eyes with SDD may correlate with a decrease in retinal function in intermediate AMD eyes independent of neovascular complications or outer retinal pigment epithelial atrophy.

Keywords: Age-related macular degeneration; Cone density; HMM; Pseudodrusen; Subretinal drusenoid deposits.