Subretinal Glial Membranes in Eyes With Geographic Atrophy

The Border of Macular Atrophy in Age-Related Macular Degeneration: A Clinicopathologic Correlation

PURPOSE

To correlate in vivo imaging to histology in an eye with macular atrophy owing to age-related macular degeneration (AMD; complete retinal pigment epithelium [RPE] and outer retinal atrophy [cRORA]) to evaluate the utility of new optical coherence tomography (OCT) suggested by previous histology.

DESIGN

Case study with clinicopathologic correlation.

METHODS

In vivo eye-tracked cross-sectional OCT scans at 13 and 8 months before death were compared to postmortem histopathology. On OCT, the atrophy border was identified as either the descent of the external limiting membrane (ELM) toward the Bruch membrane (BrM) (representing gliosis) or the presence of choroidal hypertransmission (representing lack of shadowing by RPE). Thicknesses of RPE, basal laminar deposit (BLamD), and BrM were measured at 500 and 100 μm on the nonatrophic and atrophic sides of these borders, on in vivo eye-tracked OCT and histology matched to the same location.

RESULTS

In all OCT scans, the ELM descent was visible. The RPE-BLamD band significantly thickened toward it (P < .005), over time (P = .015 and P = .043, at 500 and 100 μm, respectively). On OCT, the ELM descent delineated a smaller atrophic area than did hypertransmission. RPE-BLamD thicknesses manually measured on OCT overestimated histologic thicknesses. BrM visibility varied with RPE status.

CONCLUSION

Visible on OCT, the ELM descent is a histopathologic atrophy border supporting new terminology of cRORA, whereas hypertransmission reveals RPE degeneration. RPE-BLamD thickening across the macula, toward the atrophy and over time is confirmed. The presence of gliosis and thick RPE-BLamD suggests that macular atrophy is a late stage in disease progression, encouraging anatomic endpoints at earlier AMD stages than atrophy enlargement.

Ocular Histopathology and Immunohistochemical Analysis in the Oldest Known Individual with Autosomal Dominant Vitreoretinochoroidopathy

PURPOSE

To assess the immunohistochemical and histopathological changes in a subject with Autosomal Dominant Vitreoretinochoroidopathy (ADVIRC).

DESIGN

Case study.

PARTICIPANT

Ninety two year-old Caucasian male with ADVIRC.

METHODS

The subject was documented clinically for 54 Years. The retina/choroid complex of the right eye was evaluated with cryosections stained with hematoxylin and eosin or periodic acid schiff reagent. Cryosections were also evaluated with immunofluorescence or alkaline phosphatase immunohistochemistry (IHC) using primary antibodies against bestrophin1, GFAP, PEDF, RPE65, TGFβ, VEGF, and vimentin. The left retina and choroid were evaluated as flat mounts using immunofluorescence. UEA lectin was used to stain viable vasculature.

MAIN OUTCOME MEASURES

The immunohistochemical and histopathological changes in retina and choroid from a subject with ADVIRC.

RESULTS

The subject had a heterozygous c.248G>A variant in exon 4 of the BEST1 gene. There was widespread chorioretinal degeneration and atrophy except for an island of spared RPE monolayer in the perimacula/macula OU. In this region, some photoreceptors were present, choriocapillaris was spared, and retinal pigment epithelial cells were in their normal disposition. There was a Muller cell periretinal membrane throughout much of the fundus. Bestrophin-1 was not detected or only minimally present by IHC in the ADVIRC RPE, even in the spared RPE area. Beyond the island of retained RPE monolayer on Bruch's membrane (BrMb), there was migration of RPE into the neuro-retina, often ensheathing blood vessels and producing excessive matrix within their perivascular aggregations.

CONCLUSIONS

The primary defect in ADVIRC is in RPE, the only cells in the eye that express the BEST1 gene. The dysfunctional RPE cells may go through epithelial/mesenchymal transition as they migrate from BrMb to form papillary aggregations in the neuro-retina, often ensheathing blood vessels. This may be the reason for retinal blood vessel nonperfusion. Migration of RPE from BrMb was also associated with attenuation of the choriocapillaris.

Clinicopathologic Correlation of Anti-Vascular Endothelial Growth Factor-Treated Type 3 Neovascularization in Age-Related Macular Degeneration

PURPOSE

To correlate histologic results with previously recorded multimodal imaging results from a patient with type 3 neovascularization secondary to age-related macular degeneration (AMD).

DESIGN

Case study, clinical imaging, laboratory imaging, and eye-tracked clinicopathologic correlation.

PARTICIPANT

An 86-year-old white woman with type 3 neovascularization secondary to AMD treated with 6 intravitreal injections of bevacizumab.

METHODS

Multimodal retinal imaging at each clinic visit was correlated with ex vivo and high-resolution histologic images of the preserved donor eye. Clinical imaging included serial near-infrared reflectance and eye-tracked spectral-domain OCT. Eye tracking, applied to the donor eye, enabled identification of histologic features corresponding to clinical OCT signatures.

MAIN OUTCOME MEASURES

Histologic correlates for clinical OCT signatures were sought, including reflectivity of the vascular complex, intraretinal hyperreflective foci and intraretinal cellularity, analysis of the topography of pathologic features, and evaluation of the sub-retinal pigment epithelium (RPE) plus basal lamina (BL) space.

RESULTS

Clinical imaging showed a deep neovascular lesion in close relationship with a mixed serous and drusenoid pigment epithelium detachment (PED), characteristic of type 3 neovascularization. Antiangiogenic therapy achieved a complete resolution of exudation. The PED progressively flattened with each treatment, leaving a persistent triangular hyperreflectivity in the outer retina. This persistent deep lesion histologically correlated with a vascular complex implanted into sub-RPE basal laminar deposit. No connection between the choriocapillaris and the sub-RPE plus BL space was observed. Both RPE-derived and lipid-filled cells were correlated with clinical intraretinal hyperreflective foci. The sub-RPE plus BL space contained macrophages, lymphocytes, Müller cell processes, and subducted RPE.

CONCLUSIONS

Clinicopathologic correlation of type 3 neovascularization showed vascular elements of retinal origin accompanied by collagenous material and Müller cell processes implanting into thick sub-RPE basal laminar deposit, which may simulate the appearance of chorioretinal anastomosis. Surrounding RPE-derived and lipid-filled cells thought to be microglia correlated with clinical intraretinal hyperreflective foci.