Reticular pseudodrusen in early age-related macular degeneration are associated with choroidal thinning

PURPOSE: To compare choroidal thickness (CT) measurements in early AMD between patients with and without reticular pseudodrusen (RPD) using spectral-domain optical coherence tomography (SD-OCT).

METHODS: This cross-sectional study examined 84 age- and sex-matched AMD patients (40 RPD [63 eyes], 44 non-RPD [75 eyes]). Fundus photographs and scanning laser ophthalmoscopy images were graded to identify RPD and non-RPD groups by three retinal specialists (MO, SY, SB) who were masked to corresponding SD-OCTs. CT at the fovea and 2400 to 3000 μm superior and inferior to the fovea was measured on SD-OCT by a grader (AG) and reviewed by a retinal specialist (SB). Only images with a clear posterior choroidal margin were analyzed (six eyes excluded due to poor image quality), and enhanced depth imaging SD-OCT was used when available (20 of 138 eyes). Greatest retinal thickness (RT) on horizontal foveal SD-OCT was also recorded.

RESULTS: Mean CTs in the superior, foveal, and inferior macula in RPD (191.3 μm ± 57.9 SD, 176.3 μm ± 60.5 SD, 179.7 μm ± 56.24 SD) were significantly less than that of non-RPD (228.0 μm ± 66.1 SD, 216.5 μm ± 70.3 SD, 224.4 μm ± 71.9 SD; P = 0.0010, P = 0.0005, P = 0.0001, respectively), as was greatest RT (P = 0.0301).

CONCLUSIONS: CT was thinner throughout the macula in the RPD group as compared with the non-RPD group. The current analysis supports an association between RPD and a thinned choroidal layer and is consistent with a choroidal etiology of RPD. CT may be integral to understanding RPD, and may be helpful in stratifying AMD progression risk.