Pachychoroid neovasculopathy falls within a spectrum of diseases associated with choroidal thickening that includes pachychoroid pigment epitheliopathy, central serous chorioretinopathy, and polypoidal choroidal vasculopathy and should be considered as a possible diagnosis in eyes with features of Type 1 neovascularization and choroidal thickening in the absence of characteristic age-related macular degeneration or degenerative changes. Pachychoroid neovasculopathy may occur as a focal abnormality within the macula, even in myopic eyes with normal subfoveal choroidal thickness. Pachychoroid neovasculopathy can ultimately progress to the development of polypoidal choroidal vasculopathy.
Spectral domain optical coherence tomography imaging showed that a subset of patients with LMH had an epiretinal proliferation with medium reflectivity and no evidence of contractile properties that was contiguous with layers of the mid-retina. This phenotype differs from conventionally described ERMs in appearance and induced changes of the underlying retina. Given these distinct anatomical relationships, the presence of LHEP could affect surgical outcomes.
Eyes with LMH and LHEP were associated with poorer visual acuity, larger LMH diameters, thinner retinal thickness, and higher incidence of ellipsoid disruption compared with eyes without LHEP, suggesting a process involving more severe retinal tissue loss and injury. Both LMH with and without LHEP seemed to be stable configurations over time.
Purpose
To investigate the frequency, natural evolution and histological correlates of layered, hyperreflective, sub-retinal pigment epithelium (sub-RPE) lines, known as the Onion Sign, in neovascular age-related macular degeneration (nvAMD).
Design
Retrospective observational cohort study; an experimental laboratory study.
Participants
Two hundred thirty eyes of 150 consecutive patients with nvAMD; 40 human donor eyes with clinical and histopathologic diagnosis of nvAMD.
Methods
Spectral-domain optical coherence tomography (SD-OCT), near-infrared reflectance (nIR), color fundus images and medical charts were reviewed. Donor eyes underwent multimodal ex vivo imaging including SD-OCT before processing for high-resolution histology.
Main Outcome Measures
Presence of layered, hyperreflective sub-RPE lines, qualitative analysis of their change in appearance over time with SD-OCT, histological correlates of these lines, and associated findings within surrounding tissues.
Results
Sixteen of 230 eyes of patients (7.0%) and 2 of 40 donor eyes (5.0%) with nvAMD had layered, hyperreflective sub-RPE lines on SD-OCT imaging. These appeared as refractile, yellow-gray exudates on color imaging and hyperreflective lesions on nIR. In all 16 eyes, the Onion Sign persisted in follow-up for up to 5 years, with fluctuations in the abundance of lines and associated with intraretinal hyperreflective foci. Patients with the Onion Sign were disproportionately taking cholesterol-lowering medications (p = 0.025). Histology of 2 donor eyes revealed that hyperreflective lines correlated with clefts created by extraction of cholesterol crystals during tissue processing. Fluid surrounding crystals contained lipid yet was distinct from oily drusen. Intraretinal hyperreflective foci correlated with intraretinal RPE and lipid-filled cells of probable monocyte origin.
Conclusion
Persistent and dynamic, the Onion Sign represents sub-RPE cholesterol crystal precipitation in aqueous environment. The frequency of the Onion Sign in nvAMD in a referral practice and a pathology archive is 5–7%. Associations include use of cholesterol-lowering medication and intraretinal hyperreflective foci attributable to RPE cells and lipid-filled cells of monocyte origin.
Lamellar macular hole with LHEP may demonstrate closure after pars plana vitrectomy with LHEP and internal limiting membrane peeling and gas tamponade. There was considerable improvement in visual acuity. It is possible that LHEP originates from middle retinal layers of the lamellar hole defect because it contains retinal glial cells, specifically Müller cells.
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