Deepayan Kar

University of Alabama at Birmingham | UAB · Department of Ophthalmology

PURPOSE: To describe baseline quantitative (short-wavelength) autofluorescence (qAF) findings in a large pseudophakic cohort at age-related macular degeneration (AMD)’s beginnings; to assess qAF8 as an outcome measure and evaluate AREDS and Beckman grading systems. METHODS: In the ALSTAR2 baseline cohort (NCT04112667), 346 pseudophakic eyes of 188...

A progression sequence for age-related macular degeneration onset may be determinable with consensus neuroanatomical nomenclature augmented by drusen biology and eye-tracked clinical imaging. This narrative review proposes to supplement the Early Treatment of Diabetic Retinopathy Study (sETDRS) grid with a ring to capture high rod densities. Publis...

Purpose Despite the centrality of the retinal pigment epithelium (RPE) in vision and retinopathy our picture of RPE morphology is incomplete. With a volumetric reconstruction of human RPE ultrastructure, we aim to characterize major membranous features including apical processes and their interactions with photoreceptor outer segments, basolateral...

Purpose Progress toward treatment and prevention of age-related macular degeneration (AMD) requires imaging end points that relate to vision. We investigated choriocapillaris flow signal deficits (FD%) and visual function in eyes of individuals aged ≥60 years, with and without AMD. Methods One eye of each participant in the baseline visit of the A...

Mitochondria are candidate reflectivity signal sources in optical coherence tomography (OCT) retinal imaging. Here, we use deep-learning-assisted volume electron microscopy of human retina and in vivo imaging to map mitochondria networks in the outer plexiform layer (OPL), where photoreceptors synapse with second-order interneurons. We observed alt...

Purpose: We evaluate the impact of test target location in assessing rod-mediated dark adaptation (RMDA) along the transition from normal aging to intermediate age-related macular degeneration (AMD). We consider whether RMDA slows because the test locations are near mechanisms leading to or resulting from high-risk extracellular deposits. Soft dru...

Purpose: Ultrahigh resolution spectral domain-OCT (UHR SD-OCT) enables in vivo visualization of micrometric structural markers which differentially associate with normal aging versus age-related macular degeneration (AMD). This study explores the hypothesis that UHR SD-OCT can detect and quantify sub-retinal pigment epithelium (RPE) deposits in ea...

Purpose: Quantification of retinal xanthophyll carotenoids in eyes with and without age-related macular degeneration (AMD) via macular pigment optical volume (MPOV), a metric for xanthophyll abundance from dual wavelength autofluorescence, plus correlations to plasma levels, could clarify the role of lutein (L) and zeaxanthin (Z) in health, AMD pro...

Purpose: We hypothesize the first visual dysfunction in transitioning to early and intermediate age-related macular degeneration (AMD) is delayed rod-mediated dark adaptation (RMDA), owing to impaired photoreceptor sustenance from the circulation. This analysis from the Alabama Study on Early Age-related Macular Degeneration 2 provides insight on...

Mitochondria are organelles essential for cellular metabolism that also contribute reflectivity to optical coherence tomography (OCT) via Mie scattering. To find reflectivity sources, we assessed mitochondrial distribution of outer plexiform layer (OPL) using comprehensive volume electron microscopy. Parafoveal retina of a 21-year-old male donor wa...

Purpose : To evaluate hypotheses about the role of acquired vitelliform lesion (AVL) in age-related macular degeneration (AMD) pathophysiology. Design : Laboratory histology study; retrospective, observational case series Methods : Two donor eyes in a research archive with AVL and AMD were analyzed with light and electron microscopy for AVL conte...

Purpose: By optical coherence tomography (OCT) imaging, hyperreflective foci (HRF) indicate progression risk for advanced age-related macular degeneration (AMD) and are in part attributable to ectopic retinal pigment epithelium (RPE). We hypothesized that ectopic RPE are molecularly distinct from in-layer cells and that their cross-retinal course...

Age-related macular degeneration (AMD) is a common sight-threatening disease of older adults and treatment options are needed. Abnormalities of retinal pigment epithelium (RPE), supporting cells to photoreceptors and capillaries, are a hallmark. Clinical optical coherence tomography (OCT) imaging reveals hyperreflective foci (HRF) that confer risk...

Purpose: Basal linear deposit (BLinD) is a thin layer of soft drusen material. To elucidate the biology of extracellular deposits conferring age-related macular degeneration (AMD) progression risk and inform multimodal clinical imaging based on optical coherence tomography (OCT), we examined lipid content and regional prevalence of BLinD, soft dru...

Purpose: We assessed the association between the abundance of macular xanthophyll carotenoid pigment using dual-wavelength autofluorescence and multimodal vision testing including rod-mediated dark adaptation (RMDA), a measure of retinoid re-supply, in adults ≥60 years old with and without age-related macular degeneration (AMD). Methods: AMD sev...

Purpose Hyperreflective foci (HRF) are optical coherence tomography (OCT) biomarkers for progression of non-neovascular age-related macular degeneration (AMD) attributed to anteriorly migrated retinal pigment epithelial (RPE) cells. We examined associations between rod- and cone-mediated vision and HRF plus smaller hyperreflective specks (HRS); we...