Purpose
To describe outer retinal findings in eyes with severe atrophy associated with age-related macular degeneration (AMD) using spectral-domain optical coherence tomography (SD-OCT) and suggest candidate histopathologic correlates.
Methods
We retrospectively reviewed medical records of AMD patients with severe atrophy due to either choroidal neovascularization (CNV) or geographic atrophy (GA). The findings were evaluated in SD-OCT images, and compared with histopathologic findings in donor eyes with GA or CNV stained with periodic acid-Schiff-hematoxylin or toluidine blue. Some OCT images had volume rendering using the program Medical Image Processing, Analysis, and Visualization.
Results
In 25 eyes of 16 patients (mean age, 82.7 ± 7.9 years) with AMD (20 eyes with CNV and 5 eyes with GA), a sheet of moderately reflective material was identified above the Bruch membrane line within the atrophic area in the SD-OCT images. At its external border the material was contiguous with the outer portion of the retinal pigment epithelium (RPE) band. Below the material was a relatively hyporeflective space. The material seen was thrown into folds in more widespread cases following CNV. Histopathology revealed a rippled layer of basal laminar deposits (BlamD) in an area of RPE atrophy in 7 of 9 donor eyes with GA (mean age, 87.3 ± 4.4 years) stained with periodic acid-Schiff-hematoxylin. High-resolution histology section stained with toluidine blue revealed that below persistent BlamD there were cells of retinal origin, calcified drusen, or CNV. In some Müller cell processes seemed to extend under and undermine BlamD. The mean thickness of persistent BlamD of 36 donor eyes with CNV and 10 donor eyes with GA (mean age, 85.6 ± 6.7 years) was 9.5 ± 8.9 μm, but some of them were very thick (the maximum thickness was 71.9 μm).
Conclusions
BlamD, which get thicker and often do not go away with the progression of AMD, is common in specimens of GA and CNV. We have described a new entity, termed outer retinal corrugations, which may correspond to histological BlamD, an extracellular deposit that persists in eyes with AMD. The visualization of the material suggests that at least in some AMD eyes the OCT-designated RPE band may be more than just RPE. This finding in eyes with CNV does not necessarily mean there is exudation or leakage, and as a consequence these patients do not need injection based on this solitary finding.
Keywords: 412 age-related macular degeneration •
550 imaging/image analysis: clinical