Calcified nodules in retinal drusen are associated with disease progression in age-related macular degeneration

Calcified Drusen Prevent the Detection of Underlying Choriocapillaris Using Swept-Source Optical Coherence Tomography Angiography

Purpose

In age-related macular degeneration (AMD), choriocapillaris flow deficits (CCFDs) under soft drusen can be measured using established compensation strategies. This study investigated whether CCFDs can be quantified under calcified drusen (CaD).

Methods

CCFDs were measured in normal eyes (n = 30) and AMD eyes with soft drusen (n = 30) or CaD (n = 30). CCFD density masks were generated to highlight regions with higher CCFDs. Masks were also generated for soft drusen and CaD based on both structural en face OCT images and corresponding B-scans. Dice similarity coefficients were calculated between the CCFD density masks and both the soft drusen and CaD masks. A phantom experiment was conducted to simulate the impact of light scattering that arises from CaD.

Results

Area measurements of CCFDs were highly correlated with those of CaD but not soft drusen, suggesting an association between CaD and underlying CCFDs. However, unlike soft drusen, the detected optical coherence tomography (OCT) signals underlying CaD did not arise from the defined CC layer but were artifacts caused by the multiple scattering property of CaD. Phantom experiments showed that the presence of highly scattering material similar to the contents of CaD caused an artifactual scattering tail that falsely generated a signal in the CC structural layer but the underlying flow could not be detected. Similarly, CaD also caused an artifactual scattering tail and prevented the penetration of light into the choroid, resulting in en face hypotransmission defects and an inability to detect blood flow within the choriocapillaris. Upon resolution of the CaD, the CC perfusion became detectable.

Conclusions

The high scattering property of CaD leads to a scattering tail under these drusen that gives the illusion of a quantifiable optical coherence tomography angiography signal, but this signal does not contain the angiographic information required to assess CCFDs. For this reason, CCFDs cannot be reliably measured under CaD, and CaD must be identified and excluded from macular CCFD measurements.

Spectral-Domain and Swept-Source OCT Angiographic Scans Yield Similar Drusen Measurements When Processed with the Same Algorithm

Purpose

An algorithm developed to obtain drusen area and volume measurements using swept-source OCT angiography (SS-OCTA) scans was tested on spectral-domain OCT angiography (SD-OCTA) scans.

Design

Retrospective study.

Participants

Forty pairs of scans from 27 eyes with intermediate age-related macular degeneration and drusen.

Methods

Patients underwent both SD-OCTA and SS-OCTA imaging at the same visit using the 6 mm × 6 mm OCTA scan patterns. Using the same algorithm, we obtained drusen area and volume measurements within both 3 mm and 5 mm fovea-centered circles. Paired 2-sample t-tests were performed along with Pearson's correlation tests.

Main Outcome Measures

Mean square root (sqrt) drusen area and cube root (cbrt) drusen volume within the 3 mm and 5 mm fovea-centered circles.

Results

Mean sqrt drusen area values from SD-OCTA and SS-OCTA scans were 1.57 (standard deviation [SD] 0.57) mm and 1.49 (SD 0.58) mm in the 3 mm circle and 1.88 (SD 0.59) mm and 1.76 (SD 0.58) mm in the 5 mm circle, respectively. Mean cbrt drusen volume measurements were 0.54 (SD 0.19) mm and 0.51 (SD 0.20) mm in the 3 mm circle, and 0.60 (SD 0.17) mm and 0.57 (SD 0.17) mm in the 5 mm circle. Small differences in area and volume measurements were found (all P < 0.001); however, the correlations between the instruments were strong (all coefficients > 0.97; all P < 0.001).

Conclusions

An algorithm originally developed for SS-OCTA scans performs well when used to obtain drusen volume and area measurements from SD-OCTA scans; thus, a separate SD-OCT structural scan is unnecessary to obtain measurements of drusen.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Structural OCT and OCT angiography biomarkers associated with the development and progression of geographic atrophy in AMD

BACKGROUND

Geographic atrophy (GA) is an advanced, irreversible, and progressive form of age-related macular degeneration (AMD). Structural optical coherence tomography (OCT) and OCT angiography (OCTA) have been largely used to characterize this stage of AMD and, more importantly, to define biomarkers associated with the development and progression of GA in AMD.

METHODS

Articles pertaining to OCT and OCTA biomarkers related to the development and progression of GA with relevant key words were used to search in PubMed, Researchgate, and Google Scholar. The articles were selected based on their relevance, reliability, publication year, published journal, and accessibility.

RESULTS

Previous reports have highlighted various OCT and OCTA biomarkers linked to the onset and advancement of GA. These biomarkers encompass characteristics such as the size, volume, and subtype of drusen, the presence of hyperreflective foci, basal laminar deposits, incomplete retinal pigment epithelium and outer retinal atrophy (iRORA), persistent choroidal hypertransmission defects, and the existence of subretinal drusenoid deposits (also referred to as reticular pseudodrusen). Moreover, biomarkers associated with the progression of GA include thinning of the outer retina, photoreceptor degradation, the distance between retinal pigment epithelium and Bruch's membrane, and choriocapillaris loss.

CONCLUSION

The advent of novel treatment strategies for GA underscores the heightened need for prompt diagnosis and precise monitoring of individuals with this condition. The utilization of structural OCT and OCTA becomes essential for identifying distinct biomarkers associated with the initiation and progression of GA.

Extensive Macular Atrophy with Pseudodrusen-like appearance: Progression Kinetics and Late-Stage Findings

PURPOSE

To describe the clinical outcome and late-stage findings of extensive macular atrophy with pseudodrusen-like appearance (EMAP).

DESIGN

Retrospective cohort study.

PARTICIPANTS

Seventy-eight patients (156 eyes) affected by EMAP.

METHODS

We collected data on best-corrected visual acuity, kinetic perimetry, OCT, short-wavelength autofluorescence, and near-infrared autofluorescence findings. Genetic testing for the TIMP3 and C1QTNF5 genes was performed via Sanger sequencing for 58 patients, with no pathogenic variants identified.

MAIN OUTCOME MEASURES

The primary outcomes were best-corrected visual acuity at the last examination, visual field at the last examination, and incidence rates and time-to-event curves for blindness with the United States Social Security Administration and World Health Organization (WHO) criteria, foveal involvement, and atrophy enlargement beyond the 30° and 55° field of view. Imaging findings at the last examination were secondary outcomes.

RESULTS

At the most recent visit, mean age was 70.9 ± 5.2 years. Using United States criteria, 58.1% of the patients were blind, and 25.8% were blind according to WHO criteria. All eyes showed large central scotomas, which were associated with visual field constriction in 22.2% of eyes. We detected focal openings or large dehiscences of Bruch's membrane (BM) in 25.4% of eyes. Near-infrared autofluorescence showed increased visibility of the choroidal vessels beyond the atrophy in 87.2% of eyes. The incidence rates for blindness were 3.95 per 100 patient-years with United States criteria and 1.54 per 100 patient-years according to WHO criteria. The incidence rates were 22.8 per 100 eye-years for foveal involvement, 12.0 per 100 eye-years for atrophy enlargement beyond 30°, and 6.6 per 100 eye-years for atrophy enlargement beyond 55°. The estimates were not influenced by the age at onset.

CONCLUSIONS

We identified characteristic imaging findings, including BM ruptures, in elder patients with EMAP and calculated incidence rates for different functional and anatomic outcomes.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Non-Neovascular Age-Related Macular Degeneration Assessment: Focus on Optical Coherence Tomography Biomarkers

The imagistic evaluation of non-neovascular age-related macular degeneration (AMD) is crucial for diagnosis, monitoring progression, and guiding management of the disease. Dry AMD, characterized primarily by the presence of drusen and retinal pigment epithelium atrophy, requires detailed visualization of the retinal structure to assess its severity and progression. Several imaging modalities are pivotal in the evaluation of non-neovascular AMD, including optical coherence tomography, fundus autofluorescence, or color fundus photography. In the context of emerging therapies for geographic atrophy, like pegcetacoplan, it is critical to establish the baseline status of the disease, monitor the development and expansion of geographic atrophy, and to evaluate the retina's response to potential treatments in clinical trials. The present review, while initially providing a comprehensive description of the pathophysiology involved in AMD, aims to offer an overview of the imaging modalities employed in the evaluation of non-neovascular AMD. Special emphasis is placed on the assessment of progression biomarkers as discerned through optical coherence tomography. As the landscape of AMD treatment continues to evolve, advanced imaging techniques will remain at the forefront, enabling clinicians to offer the most effective and tailored treatments to their patients.

Optical coherence tomography biomarkers in early and intermediate age-related macular degeneration: A clinical guide

Advanced forms of age-related macular degeneration (AMD), characterised by atrophic and neovascular changes, are a leading cause of vision loss in the elderly population worldwide. Prior to the development of advanced AMD, a myriad of risk factors from the early and intermediate stages of AMD have been published in the scientific literature over the last years. The ability to precisely recognise structural and anatomical changes in the ageing macula, altogether with the understanding of the individual risk implications of each one of them is key for an accurate and personalised diagnostic assessment. The present review aims to summarise updated evidence of the relative risk conferred by diverse macular signs, commonly seen on optical coherence tomography, in terms of progression to geographic atrophy or macular neovascularization. This information may also serve as a basis for tailored follow-up monitoring visits.

Solid-state NMR MAS CryoProbe enables structural studies of human blood protein vitronectin bound to hydroxyapatite

The low sensitivity of nuclear magnetic resonance (NMR) is a major bottleneck for studying biomolecular structures of complex biomolecular assemblies. Cryogenically cooled probe technology overcomes the sensitivity limitations enabling NMR applications to challenging biomolecular systems. Here we describe solid-state NMR studies of the human blood protein vitronectin (Vn) bound to hydroxyapatite (HAP), the mineralized form of calcium phosphate, using a CryoProbe designed for magic angle spinning (MAS) experiments. Vn is a major blood protein that regulates many different physiological and pathological processes. The high sensitivity of the CryoProbe enabled us to acquire three-dimensional solid-state NMR spectra for sequential assignment and characterization of site-specific water-protein interactions that provide initial insights into the organization of the Vn-HAP complex. Vn associates with HAP in various pathological settings, including macular degeneration eyes and Alzheimer's disease brains. The ability to probe these assemblies at atomic detail paves the way for understanding their formation.

Bruch's Membrane Calcification in Pseudoxanthoma Elasticum: Comparing Histopathology and Clinical Imaging

Purpose

To investigate the histology of Bruch's membrane (BM) calcification in pseudoxanthoma elasticum (PXE) and correlate this to clinical retinal imaging.

Design

Experimental study with clinicopathological correlation.

Subjects and Controls

Six postmortem eyes from 4 PXE patients and 1 comparison eye from an anonymous donor without PXE. One of the eyes had a multimodal clinical image set for comparison.

Methods

Calcification was labeled with OsteSense 680RD, a fluorescent dye specific for hydroxyapatite, and visualized with confocal microscopy. Scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy (SEM-EDX) and time-of-flight secondary ion mass spectrometry (TOF-SIMs) were used to analyze the elemental and ionic composition of different anatomical locations. Findings on cadaver tissues were compared with clinical imaging of 1 PXE patient.

Main Outcome Measures

The characteristics and topographical distribution of hydroxyapatite in BM in eyes with PXE were compared with the clinical manifestations of the disease.

Results

Analyses of whole-mount and sectioned PXE eyes revealed an extensive, confluent OsteoSense labeling in the central and midperipheral BM, transitioning to a speckled labeling in the midperiphery. These areas corresponded to hyperreflective and isoreflective zones on clinical imaging. Scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy and TOF-SIMs analyses identified these calcifications as hydroxyapatite in BM of PXE eyes. The confluent fluorescent appearance originates from heavily calcified fibrous structures of both the collagen and the elastic layers of BM. Calcification was also detected in an aged comparison eye, but this was markedly different from PXE eyes and presented as small snowflake-like deposits in the posterior pole.

Conclusions

Pseudoxanthoma elasticum eyes show extensive hydroxyapatite deposition in the inner and outer collagenous and elastic BM layers in the macula with a gradual change toward the midperiphery, which seems to correlate with the clinical phenotype. The snowflake-like calcification in BM of an aged comparison eye differed markedly from the extensive calcification in PXE.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Deep-learning-based automated measurement of outer retinal layer thickness for use in the assessment of age-related macular degeneration, applicable to both swept-source and spectral-domain OCT imaging

Effective biomarkers are required for assessing the progression of age-related macular degeneration (AMD), a prevalent and progressive eye disease. This paper presents a deep learning-based automated algorithm, applicable to both swept-source OCT (SS-OCT) and spectral-domain OCT (SD-OCT) scans, for measuring outer retinal layer (ORL) thickness as a surrogate biomarker for outer retinal degeneration, e.g., photoreceptor disruption, to assess AMD progression. The algorithm was developed based on a modified TransUNet model with clinically annotated retinal features manifested in the progression of AMD. The algorithm demonstrates a high accuracy with an intersection of union (IoU) of 0.9698 in the testing dataset for segmenting ORL using both SS-OCT and SD-OCT datasets. The robustness and applicability of the algorithm are indicated by strong correlation (r = 0.9551, P < 0.0001 in the central-fovea 3 mm-circle, and r = 0.9442, P < 0.0001 in the 5 mm-circle) and agreement (the mean bias = 0.5440 um in the 3-mm circle, and 1.392 um in the 5-mm circle) of the ORL thickness measurements between SS-OCT and SD-OCT scans. Comparative analysis reveals significant differences (P < 0.0001) in ORL thickness among 80 normal eyes, 30 intermediate AMD eyes with reticular pseudodrusen, 49 intermediate AMD eyes with drusen, and 40 late AMD eyes with geographic atrophy, highlighting its potential as an independent biomarker for predicting AMD progression. The findings provide valuable insights into the ORL alterations associated with different stages of AMD and emphasize the potential of ORL thickness as a sensitive indicator of AMD severity and progression.

Epidemiology of geographic atrophy and its precursor features of intermediate age-related macular degeneration

Globally age-related macular degeneration (AMD) is a leading cause of blindness with a significant impact on quality of life. Geographic atrophy (GA) is the atrophic late form of AMD and its prevalence increases markedly with age with around 1 in 5 persons aged 85 and above having GA in at least one eye. Bilateral GA leads to severe visual impairment thus posing a significant burden on patients, careers and health providers. The incidence and prevalence of GA varies across different geographic regions, with the highest rates in those of European ancestry. Although heterogeneity in definitions of GA and reporting strategy can explain some of the discrepancies, the data overall are consistent in showing a lower prevalence in other ethnicities such as those of Asian heritage. This is at present unexplained but thought to be due to the existence of protective factors such as differences in eye pigmentation, diet, environmental exposures and genetic variability. This review covers key aspects of the prevalence and incidence of the ocular precursor features of GA (large drusen, pigmentary abnormalities and reticular pseudo-drusen), the late stage of GA and factors that have been known to be associated with modifying risk including systemic, demographic, environment, genetic and ocular. Understanding the global epidemiology scenario is crucial for the prevention of and management of patients with GA.

Treating patients with geographic atrophy: are we there yet?

Geographic atrophy (GA) is a progressive degenerative disease that significantly contributes to visual impairment in individuals aged 50 years and older. The development of GA is influenced by various modifiable and non-modifiable risk factors, including age, smoking, and specific genetic variants, particularly those related to the complement system regulators. Given the multifactorial and complex nature of GA, several treatment approaches have been explored, such as complement inhibition, gene therapy, and cell therapy. The recent approval by the Food and Drug Administration of pegcetacoplan, a complement C3 inhibitor, marks a significant breakthrough as the first approved treatment for GA. Furthermore, numerous interventions are currently in phase II or III trials, alongside this groundbreaking development. In light of these advancements, this review provides a comprehensive overview of GA, encompassing risk factors, prevalence, genetic associations, and imaging characteristics. Additionally, it delves into the current landscape of GA treatment, emphasizing the latest progress and future considerations. The goal of starting this discussion is to ultimately identify the most suitable candidates for each therapy, highlight the importance of tailoring treatments to individual cases, and continue monitoring the long-term implications of these emerging interventions.

Imaging Histology Correlations of Intraretinal Fluid in Neovascular Age-Related Macular Degeneration

Purpose

Fluid presence and dynamism is central to the diagnosis and management of neovascular age-related macular degeneration. On optical coherence tomography (OCT), some hyporeflective spaces arise through vascular permeability (exudation) and others arise through degeneration (transudation). Herein we determined whether the histological appearance of fluid manifested this heterogeneity.

Methods

Two eyes of a White woman in her 90s with anti-vascular endothelial growth factor treated bilateral type 3 neovascularization secondary to age-related macular degeneration were osmicated, prepared for submicrometer epoxy resin sections, and correlated to eye-tracked spectral domain OCT. Examples of intraretinal tissue fluid were sought among similarly prepared donor eyes with fibrovascular scars, in a web-based age-related macular degeneration histopathology resource. Fluid stain intensity was quantified in reference to Bruch's membrane and the empty glass slide.

Results

Exudative fluid by OCT was slightly reflective and dynamically responded to anti-vascular endothelial growth factor. On histology, this fluid stained moderately, possessed a smooth and homogenous texture, and contained blood cells and fibrin. Nonexudative fluid in degenerative cysts and in outer retinal tubulation was minimally reflective on OCT and did not respond to anti-vascular endothelial growth factor. By histology, this fluid stained lightly, possessed a finely granular texture, and contained mainly tissue debris. Quantification supported the qualitative impressions of fluid stain density. Cells containing retinal pigment epithelium organelles localized to both fluid types.

Conclusions

High-resolution histology of osmicated tissue can distinguish between exudative and nonexudative fluid, some of which is transudative.

Translational Relevance

OCT and histological features of different fluid types can inform clinical decision-making and assist in the interpretation of newly available automated fluid detection algorithms.

Endpoints for clinical trials in ophthalmology

With the identification of novel targets, the number of interventional clinical trials in ophthalmology has increased. Visual acuity has for a long time been considered the gold standard endpoint for clinical trials, but in the recent years it became evident that other endpoints are required for many indications including geographic atrophy and inherited retinal disease. In glaucoma the currently available drugs were approved based on their IOP lowering capacity. Some recent findings do, however, indicate that at the same level of IOP reduction, not all drugs have the same effect on visual field progression. For neuroprotection trials in glaucoma, novel surrogate endpoints are required, which may either include functional or structural parameters or a combination of both. A number of potential surrogate endpoints for ophthalmology clinical trials have been identified, but their validation is complicated and requires solid scientific evidence. In this article we summarize candidates for clinical endpoints in ophthalmology with a focus on retinal disease and glaucoma. Functional and structural biomarkers, as well as quality of life measures are discussed, and their potential to serve as endpoints in pivotal trials is critically evaluated.

Multiscale multimodal characterization and simulation of structural alterations in failed bioprosthetic heart valves

Calcific degeneration is the most frequent type of heart valve failure, with rising incidence due to the ageing population. The gold standard treatment to date is valve replacement. Unfortunately, calcification oftentimes re-occurs in bioprosthetic substitutes, with the governing processes remaining poorly understood. Here, we present a multiscale, multimodal analysis of disturbances and extensive mineralisation of the collagen network in failed bioprosthetic bovine pericardium valve explants with full histoanatomical context. In addition to highly abundant mineralized collagen fibres and fibrils, calcified micron-sized particles previously discovered in native valves were also prevalent on the aortic as well as the ventricular surface of bioprosthetic valves. The two mineral types (fibres and particles) were detectable even in early-stage mineralisation, prior to any macroscopic calcification. Based on multiscale multimodal characterisation and high-fidelity simulations, we demonstrate that mineral occurrence coincides with regions exposed to high haemodynamic and biomechanical indicators. These insights obtained by multiscale analysis of failed bioprosthetic valves serve as groundwork for the evidence-based development of more durable alternatives. STATEMENT OF SIGNIFICANCE: Bioprosthetic valve calcification is a well-known clinically significant phenomenon, leading to valve failure. The nanoanalytical characterisation of bioprosthetic valves gives insights into the highly abundant, extensive calcification and disorganization of the collagen network and the presence of calcium phosphate particles previously reported in native cardiovascular tissues. While the collagen matrix mineralisation can be primarily attributed to a combination of chemical and mechanical alterations, the calcified particles are likely of host cellular origin. This work presents a straightforward route to mineral identification and characterization at high resolution and sensitivity, and with full histoanatomical context and correlation to hemodynamic and biomechanical indicators, hence providing design cues for improved bioprosthetic valve alternatives.

68Ga-bisphosphonates for the imaging of extraosseous calcification by positron emission tomography

Radiolabelled bisphosphonates (BPs) and [18F]NaF (18F-fluoride) are the two types of radiotracers available to image calcium mineral (e.g. bone), yet only [18F]NaF has been widely explored for the non-invasive molecular imaging of extraosseous calcification (EC) using positron emission tomography (PET) imaging. These two radiotracers bind calcium mineral deposits via different mechanisms, with BPs chelating to calcium ions and thus being non-selective, and [18F]NaF being selective for hydroxyapatite (HAp) which is the main component of bone mineral. Considering that the composition of EC has been reported to include a diverse range of non-HAp calcium minerals, we hypothesised that BPs may be more sensitive for imaging EC due to their ability to bind to both HAp and non-HAp deposits. We report a comparison between the 68Ga-labelled BP tracer [68Ga]Ga-THP-Pam and [18F]NaF for PET imaging in a rat model of EC that develops macro- and microcalcifications in several organs. Macrocalcifications were identified using preclinical computed tomography (CT) and microcalcifications were identified using µCT-based 3D X-ray histology (XRH) on isolated organs ex vivo. The morphological and mineral analysis of individual calcified deposits was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). PET imaging and ex vivo analysis results demonstrated that while both radiotracers behave similarly for bone imaging, the BP-based radiotracer [68Ga]Ga-THP-Pam was able to detect EC more sensitively in several organs in which the mineral composition departs from that of HAp. Our results strongly suggest that BP-based PET radiotracers such as [68Ga]Ga-THP-Pam may have a particular advantage for the sensitive imaging and early detection of EC by being able to detect a wider array of relevant calcium minerals in vivo than [18F]NaF, and should be evaluated clinically for this purpose.

Spatial Cluster Patterns of Retinal Sensitivity Loss in Intermediate Age-Related Macular Degeneration Features

Purpose

To examine spatial patterns of retinal sensitivity loss in the three key features of intermediate age-related macular degeneration (iAMD).

Methods

One-hundred individuals (53 iAMD, 47 normal) underwent 10-2 mesopic microperimetry testing in one eye. Pointwise sensitivities (dB) were corrected for age, sex, iAMD status, and co-presence of co-localized key iAMD features: drusen load, pigmentary abnormalities, and reticular pseudodrusen (RPD). Clusters (labeled by ranks of magnitude C-2, C-1, C0) were derived from pointwise sensitivities and then assessed by quadrants and eccentricity/rings.

Results

Two clusters of decreased sensitivities were evident in iAMD versus normal: C-2, -1.67 dB (95% CI (confidence intervals), -2.36 to -0.98; P < 0.0001); C-1, -0.93 dB (95% CI, -1.5 to -0.36; P < 0.01). One cluster of decreased sensitivity was independently associated each with increased drusen load (13.57 µm increase per -1 dB; P < 0.0001), pigmentary abnormalities (C-1: -2.23 dB; 95% CI, -3.36 to -1.1; P < 0.01), and RPD (C-1: -1.07 dB; 95% CI, -2 to -0.14; P < 0.01). Sensitivity loss in iAMD was biased toward the superior and central macula (P = 0.16 to <0.0001), aligning with structural distributions of features. However, sensitivity loss associated with drusen load also extended to the peripheral macula (P < 0.0001) with paracentral sparing, which was discordant with the central distribution of drusen.

Conclusions

Drusen load, pigmentary abnormalities, and RPD are associated with patterns of retinal sensitivity loss commonly demonstrating superior and central bias. Results highlighted that a clinical focus on these three key iAMD features using structural measures alone does not capture the complex, spatial extent of vision-related functional impairment in iAMD.

Translational Relevance

Defining the spatial patterns of retinal sensitivity loss in iAMD can facilitate a targeted visual field protocol for iAMD assessment.

Two-Photon Excited Fluorescence Lifetime Imaging of Tetracycline-Labeled Retinal Calcification

Deposition of calcium-containing minerals such as hydroxyapatite and whitlockite in the subretinal pigment epithelial (sub-RPE) space of the retina is linked to the development of and progression to the end-stage of age-related macular degeneration (AMD). AMD is the most common eye disease causing blindness amongst the elderly in developed countries; early diagnosis is desirable, particularly to begin treatment where available. Calcification in the sub-RPE space is also directly linked to other diseases such as Pseudoxanthoma elasticum (PXE). We found that these mineral deposits could be imaged by fluorescence using tetracycline antibiotics as specific stains. Binding of tetracyclines to the minerals was accompanied by increases in fluorescence intensity and fluorescence lifetime. The lifetimes for tetracyclines differed substantially from the known background lifetime of the existing natural retinal fluorophores, suggesting that calcification could be visualized by lifetime imaging. However, the excitation wavelengths used to excite these lifetime changes were generally shorter than those approved for retinal imaging. Here, we show that tetracycline-stained drusen in post mortem human retinas may be imaged by fluorescence lifetime contrast using multiphoton (infrared) excitation. For this pilot study, ten eyes from six anonymous deceased donors (3 female, 3 male, mean age 83.7 years, range 79-97 years) were obtained with informed consent from the Maryland State Anatomy Board with ethical oversight and approval by the Institutional Review Board.

OPTICAL COHERENCE TOMOGRAPHY FEATURES RELEVANT TO NEOVASCULAR AGE-RELATED MACULAR DEGENERATION MANAGEMENT AND NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION PROGRESSION: CLINICOPATHOLOGIC CORRELATION

PURPOSE

Clinicopathologic correlation of two optical coherence tomography (OCT) features in neovascular age-related macular degeneration.

METHODS

Case report, clinicopathologic correlation.

RESULTS

A patient in her 90s was diagnosed with Type 3 macular neovascularization secondary to age-related macular degeneration in the index right eye and underwent intravitreal antivascular endothelial growth factor treatment for 5 years. A double-layer sign on in vivo OCT was correlated to calcified drusen on histology. Furthermore, hyperfluorescence on fluorescein angiography corresponded on histology to choroidal hypertransmission on OCT and retinal pigment epithelium atrophy above calcified drusen.

CONCLUSION

A double-layer sign on OCT can represent nonneovascular subretinal pigment epithelium material including wide and flat calcific nodules. Furthermore, hyperfluorescence on FA, among different origins, can be due to a window defect corresponding to retinal pigment epithelium atrophy, which can be confirmed with OCT. Clinicopathological correlation using high-resolution histology can demonstrate the fine details available to clinical decision making through currently available in vivo OCT imaging.

SUBRETINAL LIPID GLOBULES AN EARLY BIOMARKER OF MACULAR NEOVASCULARIZATION IN EYES WITH INTERMEDIATE AGE-RELATED MACULAR DEGENERATION

PURPOSE

To explore the association between subretinal lipid globules (SLGs) detected in eyes with intermediate age-related macular degeneration with the presence of nonexudative macular neovascularization.

METHODS

This was a retrospective analysis of 113 consecutive patients with bilateral intermediate age-related macular degeneration (226 eyes) followed for a least 6 months. All eyes underwent multimodal imaging with fundus autofluorescence, spectral-domain optical coherence tomography, and optical coherence tomography angiography. Subretinal lipid globules were identified on spectral-domain optical coherence tomography as round hyporeflective lesions measuring 31 to 157 µ m located between the ellipsoid zone and the retinal pigment epithelium/Bruch membrane complex. Nonexudative macular neovascularization was detected with optical coherence tomography angiography. The features of NE-MNV lesions detected in eyes with SLGs were compared with those in eyes without SLGs.

RESULTS

Subretinal lipid globules were identified in 15 eyes of which 14 eyes (93.3%) demonstrated NE-MNV on optical coherence tomography angiography. In the remaining 98 eyes without SLGs, 18 (18.4%) displayed NE-AMD on optical coherence tomography angiography. The macular neovascularization area was larger in the SLG subgroup (+0.38 vs. +0.21 mm 2 , P = 0.008) and showed faster horizontal growth (+727 µ m, CI 95% 250.4, 1,205.4) than MNV in eyes without SLGs (+64.9 µ m, CI 95%, 24.3, 154) on optical coherence tomography B-scans. After a mean of 11.6 months, the conversion rate to exudative MNV was similar between eyes with SLGs and those without SLGs [8/26 (38.5%) versus 3/13 (27.3%), P = 0.56)].

CONCLUSION

The detection of SLGs in eyes with intermediate age-related macular degeneration was strongly correlated with the presence of NE-MNV. Although these MNV lesions were larger and grew faster than NE-MNV detected in eyes lacking SLGs, the rates of conversion to exudative MNV appeared similar.

Systemic disease associations with angioid streaks in a large healthcare claims database

BACKGROUND/OBJECTIVES

To assess systemic associations of angioid streaks (AS) using a large US healthcare database.

SUBJECTS/METHODS

A retrospective cross-sectional study was conducted of patients diagnosed with AS in a large, national US insurer from 2000-2019. Cases were matched 1:5 to controls. The prevalence rates of established associated disease states and other systemic diseases were calculated and compared using logistic regression. Additionally, the rate of anti-VEGF treatment was assessed as a proxy for the incidence of choroidal neovascularization (CNV).

RESULTS

One thousand eight hundred fifty-two cases of AS and 9028 matched controls were included. The rates of association between AS and the well-characterized conditions included: Pseudoxanthoma elasticum (PXE)-228 patients (12.3%), Ehlers-Danlos syndrome-18 patients (1.0%), Paget's disease-6 patients (0.3%), hemoglobinopathies-30 patients (1.6%), and idiopathic-1573 patients (84.9%). There was a statistically higher prevalence of the following less classically associated diseases among patients with AS compared to controls: hereditary spherocytosis (1.7% vs. 0.6%, p < 0.001), connective tissue disease (1.0% vs 0.3%, p < 0.001) and non-exudative age-related macular degeneration (33.9% vs 10.6%, p < 0.001). Among 1442 eligible cases analyzed, 427 (29.6%) received at least 1 anti-VEGF injection with 338 (23.4%) patients having the injection after their AS diagnosis.

CONCLUSIONS

In the largest collection of AS patients to date, the classical teaching of systemic disease associations occur at rates far, far lower than previously reported. The association of AS with other less reported diseases highlights new potential associations and may contribute to the understanding of AS formation.

Fluorescence Lifetime Imaging of Human Sub-RPE Calcification In Vitro Following Chlortetracycline Infusion

We have shown that all sub-retinal pigment epithelial (sub-RPE) deposits examined contain calcium phosphate minerals: hydroxyapatite (HAP), whitlockite (Wht), or both. These typically take the form of ca. 1 μm diameter spherules or >10 μm nodules and appear to be involved in the development and progression of age-related macular degeneration (AMD). Thus, these minerals may serve as useful biomarkers the for early detection and monitoring of sub-RPE changes in AMD. We demonstrated that HAP deposits could be imaged in vitro by fluorescence lifetime imaging microscopy (FLIM) in flat-mounted retinas using legacy tetracycline antibiotics as selective sensors for HAP. As the contrast on a FLIM image is based on the difference in fluorescence lifetime and not intensity of the tetracycline-stained HAP, distinguishing tissue autofluorescence from the background is significantly improved. The focus of the present pilot study was to assess whether vascular perfusion of the well tolerated and characterized chlortetracycline (widely used as an orally bioavailable antibiotic) can fluorescently label retinal HAP using human cadavers. We found that the tetracycline delivered through the peripheral circulation can indeed selectively label sub-RPE deposits opening the possibility for its use for ophthalmic monitoring of a range of diseases in which deposit formation is reported, such as AMD and Alzheimer disease (AD).

Clinicopathologic Findings in Three Siblings With Geographic Atrophy

Purpose

Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly worldwide. Clinical imaging and histopathologic studies are crucial to understanding disease pathology. This study combined clinical observations of three brothers with geographic atrophy (GA), followed for 20 years, with histopathologic analysis.

Methods

For two of the three brothers, clinical images were taken in 2016, 2 years prior to death. Immunohistochemistry, on both flat-mounts and cross sections, histology, and transmission electron microscopy were used to compare the choroid and retina in GA eyes to those of age-matched controls.

Results

Ulex europaeus agglutinin (UEA) lectin staining of the choroid demonstrated a significant reduction in the percent vascular area and vessel diameter. In one donor, histopathologic analysis demonstrated two separate areas with choroidal neovascularization (CNV). Reevaluation of swept-source optical coherence tomography angiography (SS-OCTA) images revealed CNV in two of the brothers. UEA lectin also revealed a significant reduction in retinal vasculature in the atrophic area. A subretinal glial membrane, composed of processes positive for glial fibrillary acidic protein and/or vimentin, occupied areas identical to those of retinal pigment epithelium (RPE) and choroidal atrophy in all three AMD donors. SS-OCTA also demonstrated presumed calcific drusen in the two donors imaged in 2016. Immunohistochemical analysis and alizarin red S staining verified calcium within drusen, which was ensheathed by glial processes.

Conclusions

This study demonstrates the importance of clinicohistopathologic correlation studies. It emphasizes the need to better understand how the symbiotic relationship between choriocapillaris and RPE, glial response, and calcified drusen impact GA progression.

OCT Risk Factors for Development of Atrophy in Eyes with Intermediate Age-Related Macular Degeneration

PURPOSE

To determine the frequency of multiple OCT biomarkers of intermediate age-related macular degeneration (iAMD) and their relationship with the development of complete retinal pigment epithelium and outer retinal atrophy (cRORA) after 2 years.

DESIGN

Retrospective cohort study.

PARTICIPANTS

This retrospective analysis included 330 eyes of 330 consecutive patients with iAMD in ≥ 1 eye who had 24 months of follow-up data.

METHODS

Spectralis OCT volume scans (49 B-scans over 6 × 6 mm, automatic real time = 6, fovea-centered) at baseline were evaluated for the previously described iAMD biomarkers, including a high-central drusen volume (DV; ≥ 0.03 mm³), intraretinal hyper-reflective foci (IHRF), subretinal drusenoid deposits (SDDs), hypo-reflective drusen cores (hDCs), and a thin or thick (multilayered) double-layer sign (DLS). The age-related macular degeneration (AMD) status in the fellow eye was also assessed and classified as normal or early AMD, iAMD, exudative macular neovascularization, or cRORA.

MAIN OUTCOME MEASURES

Incidence of cRORA, odds ratio for demographics, and OCT features.

RESULTS

At month 24, 16.36% (54/330) of the iAMD eyes developed cRORA. Several baseline features, including high-central DV, IHRF, SDD, hDC, thin DLS, and cRORA in the fellow eye, were associated with a significantly greater risk for development of cRORA at 2 years. The odds ratio, 95% confidence interval, P value, and baseline frequencies of these biomarkers were DV (6.510, 2.467-17.176, P < 0.001, 49.1%), IHRF (12.763, 4.763-34.202, P < 0.001, 38.8%), SDD (2.307, 1.003-5.304, P = 0.049, 34.2%), hDC (3.012, 1.152-7.873, P = 0.024, 13.0%), thin DLS (4.517, 1.555-13.126, P = 0.006, 11.8%), and cRORA in the fellow eye (7.184, 1.938-26.623, P = 0.003, 8.2%).

CONCLUSIONS

In addition to the 4 previously reported factors that are present in a significant proportion of iAMD (DV, IHRF, hDC, and SDD), a thin DLS and cRORA in the fellow eye were associated with an increased risk of progression to cRORA over 2 years. These biomarkers may aid in prognostication, risk stratification, and selection of patients for clinical trials.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Automated segmentation and quantification of calcified drusen in 3D swept source OCT imaging

Qualitative and quantitative assessments of calcified drusen are clinically important for determining the risk of disease progression in age-related macular degeneration (AMD). This paper reports the development of an automated algorithm to segment and quantify calcified drusen on swept-source optical coherence tomography (SS-OCT) images. The algorithm leverages the higher scattering property of calcified drusen compared with soft drusen. Calcified drusen have a higher optical attenuation coefficient (OAC), which results in a choroidal hypotransmission defect (hypoTD) below the calcified drusen. We show that it is possible to automatically segment calcified drusen from 3D SS-OCT scans by combining the OAC within drusen and the hypoTDs under drusen. We also propose a correction method for the segmentation of the retina pigment epithelium (RPE) overlying calcified drusen by automatically correcting the RPE by an amount of the OAC peak width along each A-line, leading to more accurate segmentation and quantification of drusen in general, and the calcified drusen in particular. A total of 29 eyes with nonexudative AMD and calcified drusen imaged with SS-OCT using the 6 × 6 mm² scanning pattern were used in this study to test the performance of the proposed automated method. We demonstrated that the method achieved good agreement with the human expert graders in identifying the area of calcified drusen (Dice similarity coefficient: 68.27 ± 11.09%, correlation coefficient of the area measurements: r = 0.9422, the mean bias of the area measurements = 0.04781 mm²).

Optical Coherence Tomography Biomarkers for Conversion to Exudative Neovascular Age-related Macular Degeneration

PURPOSE

To identify optical coherence tomography (OCT) biomarkers, including thin and thick double-layer sign (DLS) for the progression from intermediate AMD (iAMD) to exudative macular neovascularization (MNV) over 24 months.

DESIGN

Retrospective cohort study.

METHODS

Setting: Retina consultants of Texas.

PATIENT POPULATION

458 eyes of 458 subjects with iAMD in at least 1 eye with 24 months of follow-up data.

MAIN OUTCOMES MEASURES

The following biomarkers were assessed at baseline: high central drusen volume (≥0.03 mm³), intraretinal hyper-reflective foci (IHRF), subretinal drusenoid deposits, hyporeflective drusen cores, thick DLS, thin DLS, and central choroidal thickness. A binary logistic regression was computed to investigate the association between baseline OCT covariates and the conversion to exudative MNV within 24 months. In addition, fellow eye status was also included in the model.

RESULTS

During follow-up, 18.1% (83 of 458) of eyes with iAMD progressed to exudative MNV. Thick DLS, IHRF, and fellow eye exudative MNV were found to be independent predictors for the development of exudative MNV within 2 years. The baseline frequencies, odds ratios, 95% confidence intervals, and P values for these biomarkers were as follows: thick DLS (9.6%, 4.339, 2.178-8.644; P < .001), IHRF (36.0%, 2.340, 1.396-3.922; P = 0.001), and fellow eye exudative MNV (35.8%, 1.694, 1.012-2.837; P = .045).

CONCLUSIONS

Thick DLS, IHRF, and fellow eye exudative MNV were associated with an increased risk of progression from iAMD to exudative MNV. These biomarkers, which are readily identified by the review of OCT volume scans, may aid in risk prognostication for patients and for identifying patients for early intervention trials.

Zinc Supplementation Induced Transcriptional Changes in Primary Human Retinal Pigment Epithelium: A Single-Cell RNA Sequencing Study to Understand Age-Related Macular Degeneration

Zinc supplementation has been shown to be beneficial to slow the progression of age-related macular degeneration (AMD). However, the molecular mechanism underpinning this benefit is not well understood. This study used single-cell RNA sequencing to identify transcriptomic changes induced by zinc supplementation. Human primary retinal pigment epithelial (RPE) cells could mature for up to 19 weeks. After 1 or 18 weeks in culture, we supplemented the culture medium with 125 µM added zinc for one week. RPE cells developed high transepithelial electrical resistance, extensive, but variable pigmentation, and deposited sub-RPE material similar to the hallmark lesions of AMD. Unsupervised cluster analysis of the combined transcriptome of the cells isolated after 2, 9, and 19 weeks in culture showed considerable heterogeneity. Clustering based on 234 pre-selected RPE-specific genes divided the cells into two distinct clusters, we defined as more and less differentiated cells. The proportion of more differentiated cells increased with time in culture, but appreciable numbers of cells remained less differentiated even at 19 weeks. Pseudotemporal ordering identified 537 genes that could be implicated in the dynamics of RPE cell differentiation (FDR < 0.05). Zinc treatment resulted in the differential expression of 281 of these genes (FDR < 0.05). These genes were associated with several biological pathways with modulation of ID1/ID3 transcriptional regulation. Overall, zinc had a multitude of effects on the RPE transcriptome, including several genes involved in pigmentation, complement regulation, mineralization, and cholesterol metabolism processes associated with AMD.

Biomineralogical signatures of breast microcalcifications

Microcalcifications, primarily biogenic apatite, occur in cancerous and benign breast pathologies and are key mammographic indicators. Outside the clinic, numerous microcalcification compositional metrics (e.g., carbonate and metal content) are linked to malignancy, yet microcalcification formation is dependent on microenvironmental conditions, which are notoriously heterogeneous in breast cancer. We interrogate multiscale heterogeneity in 93 calcifications from 21 breast cancer patients using an omics-inspired approach: For each microcalcification, we define a "biomineralogical signature" combining metrics derived from Raman microscopy and energy-dispersive spectroscopy. We observe that (i) calcifications cluster into physiologically relevant groups reflecting tissue type and local malignancy; (ii) carbonate content exhibits substantial intratumor heterogeneity; (iii) trace metals including zinc, iron, and aluminum are enhanced in malignant-localized calcifications; and (iv) the lipid-to-protein ratio within calcifications is lower in patients with poor composite outcome, suggesting that there is potential clinical value in expanding research on calcification diagnostic metrics to include "mineral-entrapped" organic matrix.

Automated Identification of Incomplete and Complete Retinal Epithelial Pigment and Outer Retinal Atrophy Using Machine Learning

OBJECTIVE

To assess and validate a deep learning algorithm to automatically detect incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) and complete retinal pigment epithelial and outer retinal atrophy (cRORA) in eyes with age-related macular degeneration.

DESIGN

In a retrospective machine learning analysis, a deep learning model was trained to jointly classify the presence of iRORA and cRORA within a given B-scan. The algorithm was evaluated using 2 separate and independent datasets.

PARTICIPANTS

OCT B-scan volumes from 71 patients with nonneovascular age-related macular degeneration captured at the Doheny-University of California Los Angeles Eye Centers and the following 2 external OCT B-scans testing datasets: (1) University of Pennsylvania, University of Miami, and Case Western Reserve University and (2) Doheny Image Reading Research Laboratory.

METHODS

The images were annotated by an experienced grader for the presence of iRORA and cRORA. A Resnet18 model was trained to classify these annotations for each B-scan using OCT volumes collected at the Doheny-University of California Los Angeles Eye Centers. The model was applied to 2 testing datasets to assess out-of-sample model performance.

MAIN OUTCOMES MEASURES

Model performance was quantified in terms of area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC). Sensitivity, specificity, and positive predictive value were also compared against additional clinician annotators.

RESULTS

On an independently collected test set, consisting of 1117 volumes from the general population, the model predicted iRORA and cRORA presence within the entire volume with nearly perfect AUROC performance and AUPRC scores (iRORA, 0.61; 95% confidence interval [CI] [0.45, 0.82]: cRORA, 0.83; 95% CI [0.68, 0.95]). On another independently collected set, consisting of 60 OCT B-scans enriched for iRORA and cRORA lesions, the model performed with AUROC (iRORA: 0.68, 95% CI [0.54, 0.81]; cRORA: 0.84, 95% CI [0.75, 0.94]) and AUPRC (iRORA: 0.70, 95% CI [0.55, 0.86]; cRORA: 0.82, 95% CI [0.70, 0.93]).

CONCLUSIONS

A deep learning model can accurately and precisely identify both iRORA and cRORA lesions within the OCT B-scan volume. The model can achieve similar sensitivity compared with human graders, which potentially obviates a laborious and time-consuming annotation process and could be developed into a diagnostic screening tool.

Incomplete Retinal Pigment Epithelial and Outer Retinal Atrophy: Longitudinal Evaluation in Age-Related Macular Degeneration

PURPOSE

To examine the association between incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) on OCT imaging and the subsequent risk of developing geographic atrophy (GA) defined on conventional color fundus photography (CFP) and to compare this with the specific features that define nascent GA (nGA).

DESIGN

Retrospective analysis of data from a longitudinal study.

PARTICIPANTS

A total of 280 eyes from 140 participants with bilateral large drusen without specific nGA-defining features or late age-related macular degeneration (AMD) at baseline.

METHODS

OCT imaging and CFP were performed at baseline and then at 6-month intervals for up to 36 months. Eyes that developed neovascular AMD were censored on the day it was detected. OCT volume scans were graded for the presence of iRORA and nGA separately, and CFP images were graded for the presence of GA.

MAIN OUTCOME MEASURES

Association with and variance explained in time to GA development.

RESULTS

A total of 58 eyes (21%) from 46 participants (33%) had iRORA at baseline, and a further 87 eyes (31%) developed iRORA over the follow-up period. Time-to-event analyses demonstrated that prevalent or incident iRORA was associated with an increased rate of GA development (adjusted hazard ratio [HR], 12.1; P = 0.021), as was incident nGA (adjusted HR, 78.6; P < 0.001). However, only the specific nGA features (adjusted P < 0.001), and not iRORA (adjusted P = 0.520), were associated with an increased rate of GA development when both features were included in the same multivariable model. The proportion of variance explained in the time to GA development by iRORA itself (R² = 43%) was significantly lower than explained by nGA alone (R² = 91%; P = 0.010).

CONCLUSIONS

In this cohort, iRORA is a significant risk factor for GA development, but its association with GA development appears to be accounted for by the development of the specific features that define nGA. Although requiring replication, these findings provide useful guidance on the relative utility of nGA and iRORA as risk factors for GA and as potential surrogate end points for future interventional studies in the early stages of AMD.

Differentiating drusen and drusenoid deposits subtypes on multimodal imaging and risk of advanced age-related macular degeneration

Drusen are extracellular material considered a precursor lesion to advanced age-related macular degeneration (AMD), located either on the retinal pigment epithelium (RPE) or the sub-RPE; they contain various proteins associated with inflammation and lipids. Previous studies suggest that the lifecycle of drusen varies depending on drusen type and size. In general, conventional drusen grow and aggregate/coalesce in the first stage, and in the second stage, they regress with or without showing RPE atrophy. The risk of advanced AMD also varies depending on the drusen and drusenoid deposit types' along with their size and RPE abnormalities. In eyes with macular neovascularization (MNV), specific drusen/drusenoid deposits are closely associated with the MNV subtype. Recently, pachychoroid-associated drusen (pachydrusen) were proposed and clinical findings regarding this entity have been accumulating, as more attention is focused on drusen as well as pachychoroid diseases. With the advance in imaging modalities, various modalities can show specific characteristics depending on drusen types. To assess the risk of advanced AMD, it is essential for physicians to have accurate clinical knowledge about each druse/drusenoid lesion and correctly evaluate its imaging characteristics using multimodal imaging. This review summarizes the latest clinical knowledge about each druse/drusenoid lesions and documents their imaging characteristics on multimodal imaging, allowing clinicians to better manage patients and stratify the risk of developing advanced AMD. The most representative cases are illustrated, which can be helpful in the differential diagnosis of drusen and drusenoid deposits.

Choroidal structural features of acquired vitelliform lesions in non-exudative age-related macular degeneration

PURPOSE

To define the choroidal morphological characteristics of non-exudative age-related macular degeneration (AMD) cases associated with acquired vitelliform lesions (AVLs).

METHODS

This retrospective study included intermediate AMD patients with AVLs (Group1, 21eyes) and without AVLs (Group2, 21eyes). A healthy control group was (Group3, 23eyes) also included. Subfoveal choroidal thickness (SFCT), greatest basal diameter (GBD), and maximum height (MH) of the largest PED were measured on spectral domain optical coherence tomography. Internal reflectivity of PEDs and total choroidal area (TCA) were measured using ImageJ software. The TCA was binarized to the luminal area (LA) and stromal area. The choroidal vascularity index (CVI) was assessed.

RESULTS

The mean SFCT, TCA, and LA were higher in Group 1 (290.3 ± 86.8 μm, 0.840 ± 0.302 mm², 0.602 ± 0.227 mm²) than in Group 2 (215.6 ± 85.0 μm, 0.594 ± 0.183 mm², 0.429 ± 0.139 mm²) (p = 0.014, p = 0.017, p = 0.020, respectively). There was no significant difference in the CVI measurements between Group 1 and Group 2 (p = 1.000). The mean GBD and MH of the PED was higher in Group 1 (1443 ± 595 µm, 188 ± 86 µm) than in Group 2 (851 ± 368 µm, 119 ± 38 µm) (p = <0.001, p = 0.001, respectively). Internal PED reflectivity was significantly lower in Group 1 (0.44 ± 0.21) than in Group 2 (0.66 ± 0.17) (p = <0.001). Internal PED reflectivity showed negative correlation with GBD and MH of the PED in Group 1 (r = -0.587, p = 0.005; rho = -0.448, p = 0.042, respectively). In Group 2, internal PED reflectivity had a negative correlation with MH of the PED (rho = -0.511, p = 0.018).

CONCLUSION

Non-exudative AMD patients with AVLs are more prone to have a thick choroid and large hyporeflective PEDs as compared to the those without AVLs.

Future perspectives for treating patients with geographic atrophy

Purpose

Geographic atrophy (GA) is a late-stage form of age-related macular degeneration (AMD) characterized by the expansion of atrophic lesions in the outer retina. There are currently no approved pharmacological treatments to prevent or slow the progression of GA. This review describes the progression and assessment of GA, predictive imaging features, and complement-targeting investigational drugs for GA.

Methods

A literature search on GA was conducted.

Results

Expansion of atrophic lesions in patients with GA is associated with a decline in several measures of visual function. GA lesion size has been moderately associated with measures obtained through microperimetry, whereas GA lesion size in the 1-mm diameter area centered on the fovea has been associated with visual acuity. Optical coherence tomography (OCT) can provide 3-dimensional quantitative assessment of atrophy and is useful for identifying early atrophy in GA. Features that have been found to predict the development of GA include certain drusen characteristics and pigmentary abnormalities. Specific OCT features, including hyper-reflective foci and OCT-reflective drusen substructures, have been associated with AMD disease progression. Lesion characteristics, including focality, regularity of shape, location, and perilesional fundus autofluorescence patterns, have been identified as predictors of faster GA lesion growth. Certain investigational complement-targeting drugs have shown efficacy in slowing the progression of GA.

Conclusion

GA is a progressive disease associated with irreversible vision loss. Therefore, the lack of treatment options presents a significant unmet need. OCT and drugs under investigation for GA are promising future tools for disease management.

A 2,7-dichlorofluorescein derivative to monitor microcalcifications

Herein, we report the crystal structure of 2,7-dichlorofluorescein methyl ester (DCF-ME) and its fluorescence response to hydroxyapatite binding. The reported fluorophore is very selective for staining the bone matrix and provides turn-on fluorescence upon hydroxyapatite binding. The reported fluorophore can readily pass the cell membrane of the C2C12 cell line, and it is non-toxic for the cell line. The reported fluorophore DCF-ME may find applications in monitoring bone remodeling and microcalcification as an early diagnosis tool for breast cancer and age-related macular degeneration.

Studies of the retinal microcirculation using human donor eyes and high-resolution clinical imaging: Insights gained to guide future research in diabetic retinopathy

The microcirculation plays a key role in delivering oxygen to and removing metabolic wastes from energy-intensive retinal neurons. Microvascular changes are a hallmark feature of diabetic retinopathy (DR), a major cause of irreversible vision loss globally. Early investigators have performed landmark studies characterising the pathologic manifestations of DR. Previous works have collectively informed us of the clinical stages of DR and the retinal manifestations associated with devastating vision loss. Since these reports, major advancements in histologic techniques coupled with three-dimensional image processing has facilitated a deeper understanding of the structural characteristics in the healthy and diseased retinal circulation. Furthermore, breakthroughs in high-resolution retinal imaging have facilitated clinical translation of histologic knowledge to detect and monitor progression of microcirculatory disturbances with greater precision. Isolated perfusion techniques have been applied to human donor eyes to further our understanding of the cytoarchitectural characteristics of the normal human retinal circulation as well as provide novel insights into the pathophysiology of DR. Histology has been used to validate emerging in vivo retinal imaging techniques such as optical coherence tomography angiography. This report provides an overview of our research on the human retinal microcirculation in the context of the current ophthalmic literature. We commence by proposing a standardised histologic lexicon for characterising the human retinal microcirculation and subsequently discuss the pathophysiologic mechanisms underlying key manifestations of DR, with a focus on microaneurysms and retinal ischaemia. The advantages and limitations of current retinal imaging modalities as determined using histologic validation are also presented. We conclude with an overview of the implications of our research and provide a perspective on future directions in DR research.

Sub-retinal pigment epithelium tubules in non-neovascular age-related macular degeneration

To describe a novel optical coherence tomography (OCT) signature resembling sub-retinal pigment epithelium (RPE) tubules (SRT) in non-neovascular age-related macular degeneration (AMD). Patients suffering from non-neovascular AMD with complete medical records and multimodal imaging were retrospectively revised in three different tertiary care centers. Multimodal imaging included color fundus photograph, spectral-domain OCT (Spectralis, Heidelberg Engineering, Germany), fundus autofluorescence, OCT angiography (RTVue XR Avanti, Optovue, Inc., Fremont, CA). A total of 7 eyes of 7 patients with drusenoid pigment epithelium detachment (PED) were consecutively analyzed. The sub-RPE tubules appeared as ovoidal structures with a hyperreflective contour and hyporeflective interior appreciable in the sub-RPE-basal lamina (BL) space on OCT B-scan. The anatomical location of the sub-RPE formations was lying above the Bruch’s membrane in 5/7 cases (71.4%) or floating in the sub-RPE-BL space in 2/7 cases (28.6%). En-face OCTA revealed a curvilinear tubulation-like structure corresponding to SRT without flow signal. Sub-RPE tubules represent a newly identified OCT signature observed in eyes with drusenoid PED. The presumed origin may include a variant of calcified structure or alternatively activated RPE cells with some residual BL or basal laminar deposits attracted to BrM for craving oxygen.

Risk Factors for Progression of Age-Related Macular Degeneration: Population-Based Amish Eye Study

Objective: To evaluate the optical coherence tomography (OCT)-based risk factors for progression to late age-related macular degeneration (AMD) in a population-based study of elderly Amish. Methods: A total of 1332 eyes of 666 consecutive subjects who completed a 2-year follow-up visit were included in this multicenter, prospective, longitudinal, observational study. Imaging features were correlated with 2-year incidence of late AMD development. Odds ratios for imaging features were estimated from logistic regression. Baseline OCT images were reviewed for the presence of drusen volume ≥0.03 mm3 in the central 3 mm ring, intraretinal hyperreflective foci (IHRF), hyporeflective drusen cores (hDC), subretinal drusenoid deposits (SDD), and drusenoid pigment epithelium detachment (PED). Subfoveal choroidal thickness, drusen area, and drusen volume within 3 and 5 mm circles centered on the fovea were also assessed. Results: Twenty-one (1.5%) of 1332 eyes progressed to late AMD by 2 years. The mean age of the study subjects was 65 ± 10.17 (±SD) years and 410 subjects were female. Univariate logistic regression showed that drusen area and volume in both 3 mm and 5 mm circles, subfoveal choroidal thickness, drusen volume ≥ 0.03 mm3 in the 3 mm ring, SDD, IHRF, and hDC were all associated with an increased risk for development of late AMD. The multivariate regression model identified that drusen volume in the 3 mm ring (OR: 2.59, p = 0.049) and presence of IHRF (OR: 57.06, p < 0.001) remained as independent and significant risk factors for progression to late AMD. Conclusions: This population-based study confirms previous findings from clinic-based studies that high central drusen volume and IHRF are associated with an increased risk of progression to late AMD. These findings may be of value in risk-stratifying patients in clinical practice or identifying subjects for early intervention clinical trials.

Multimodal Imaging and En Face OCT Detection of Calcified Drusen in Eyes with Age-Related Macular Degeneration

PURPOSE

En face OCT imaging was investigated as a method for the detection and monitoring of calcified drusen in eyes with nonexudative age-related macular degeneration (AMD).

DESIGN

Retrospective case series of a prospective study.

PARTICIPANTS

Patients with nonexudative AMD.

METHODS

A retrospective review was performed of same-day color fundus (CF), fundus autofluorescence (FAF), near-infrared (NIR), and en face swept-source (SS) OCT images to identify eyes with nonexudative AMD and calcified drusen. The appearance and progression of these lesions were compared using the different imaging methods.

MAIN OUTCOME MEASURES

Comparison between the presence of calcified drusen observed on CF images with the detection of these lesions on FAF, NIR, and en face SS OCT images.

RESULTS

Two hundred twenty eyes from 139 patients with nonexudative AMD were studied, with 42.7% of eyes containing calcified drusen either at baseline or during follow-up visits. On the en face SS OCT images, calcified drusen appeared as dark focal lesions referred to as choroidal hypotransmission defects (hypoTDs) that were detected in the choroid using a sub-retinal pigment epithelium (RPE) slab. The corresponding B-scans showed drusen with heterogenous internal reflectivity, hyporeflective cores, and hyperreflective caps. In most calcified drusen, choroidal hypertransmission defects (hyperTDs) were observed to develop over time around the periphery of the hypoTDs, giving them the appearance of a donut lesion on the en face SS OCT images. These donut lesions were associated with significant attenuation of the overlying retina, and the corresponding FAF images showed hypoautofluorescence at the location of these lesions. The donut lesions fulfilled the requirement for a persistent hyperTD, which is synonymous with complete RPE and outer retinal atrophy (cRORA). Six eyes displayed regression of the calcified drusen without cRORA developing. B-scans at the location of these regressed calcified drusen showed deposits along the RPE, with outer retinal thinning in the regions where the calcified lesions previously existed.

CONCLUSIONS

En face OCT imaging is a useful method for the detection and monitoring of calcified drusen and can be used to document the evolution of these drusen as they form donut lesions or foci of cRORA.

Spectral and lifetime resolution of fundus autofluorescence in advanced age-related macular degeneration revealing different signal sources

PURPOSE

To determine the fundus autofluorescence (FAF) lifetimes and spectral characteristics of individual drusen and hyperpigmentation independent of those with retinal pigment epithelium (RPE) in geographic atrophy (GA) areas in late-stage age-related macular degeneration (AMD).

METHODS

Three consecutive patients with complete RPE and outer retinal atrophy (cRORA) exhibiting drusen that were calcified or associated with hyperpigmentation were investigated with multimodal non-invasive ophthalmic imaging including colour fundus photography (CFP), optical coherence tomography (OCT), near-infrared reflectance (NIR), blue FAF and fluorescence lifetime imaging ophthalmoscopy (FLIO). Fluorescence lifetimes were measured in two spectral channels (short-wavelength spectral channel (SSC): 500-560 nm and long-wavelength spectral channel (LSC): 560-720 nm).

RESULTS

Drusen lacking RPE coverage, as confirmed by CFP and OCT, had longer FAF lifetimes than surrounding cRORA by 127 ± 66 ps (SSC) and 113 ± 48 ps (LSC, both p = 0.008 in Wilcoxon test, N = 9) and by 209 ± 100 ps (SSC) and 121 ± 56 ps (LSC, p < 0.001, N = 14) in two patients. Hyperpigmentation in CFP in a third patient shows strong FAF with prolonged lifetimes. In the SSC, persistent FAF was found inside cRORA. A crescent-shaped hyperfluorescence in an area of continuous RPE but lacking outer retina was seen in one eye with a history of anti-VEGF treatment.

CONCLUSIONS

Short-wavelength fluorescence in cRORA points to fluorophores beyond RPE organelles. Fluorescence properties of drusen within cRORA differ from in vivo drusen covered by RPE. These limited findings from three patients give new insight into the sources of FAF that can be further elucidated in larger cohorts.

Nuclear and cellular, micro and nano calcification in Alzheimer's disease patients and correlation to phosphorylated Tau

Brain calcification (calcium phosphate mineral formation) has been reported in the past 100 years in the brains of Alzheimer's disease (AD) patients. However, the association between calcification and AD, the triggers for calcification, and its role within the disease are not clear. On the other hand, hyperphosphorylated Tau protein (pTau) tangles have been widely studied and recognized as an essential factor in developing AD. In this work, calcification in the brains of AD patients is characterized by advanced electron microscopy and fluorescence microscopy. Results are then compared to samples from cognitively healthy, age-matched donors, and the colocalization of calcification and pTau is investigated. Here, we show that AD patients' brains present microcalcification associated with the neural cell nuclei and cell projections, and that these are strongly related to the presence of pTau. The link between microcalcification and pTau suggests a potential mechanism of brain cell damage. Together with the formation of amyloid plaques and neurofibrillary tangles, microcalcification in neuronal cells adds to a better understanding of the pathology of AD. Finally, the presence of microcalcification in the neuronal cells of AD patients may assist in AD diagnosis, and may open avenues for developing intervention strategies based on inhibition of calcification. STATEMENT OF SIGNIFICANCE: Brain calcification has been reported in the past 100 years in the brains of Alzheimer's disease (AD) patients. However, the association between calcification and AD is not clear. Hyperphosphorylated Tau protein (pTau) has been studied and recognized as a key factor in developing AD. We show here that AD patients' brains present microcalcification associated with the neuronal cell nuclei and cell projections, and that these are related to the presence of pTau. The study of calcification in brain cells can contribute to a better understanding of the biochemical mechanisms associated with AD and might also reveal that calcification is part of the full disease mechanism. Moreover, this work opens the possibility for using calcification as a biomarker to identify AD.

Targeted Analysis of Tears Revealed Specific Altered Metal Homeostasis in Age-Related Macular Degeneration

Purpose

Specific altered metal homeostasis has been investigated in the tear film of age-related macular degeneration (AMD) patients considering that metal dyshomeostasis contributes to the production of free radicals, inflammation, and apoptosis and results in conformational changes of proteins.

Methods

A multitargeted approach based on spectrophotometry and mass spectrometry techniques has been implemented to the multiplexed quantitation of lactoferrin (LF), S100 calcium binding protein A6 (S100A6), metallothionein 1A (MT1A), complement factor H (CFH), clusterin (CLU), amyloid precursor protein (APP), Mg, P, Na, Fe, Cu, Zn, and Ca, in the tear film from 60 subjects, 31 patients diagnosed with the dry form of AMD, and 29 healthy individuals

Results

Significant up-regulations of MT1A (1.9-fold) and S100A6 (1.4-fold) and down-regulations of LF (0.7-fold), Fe (0.6-fold), Mg (0.7-fold), and Cu (0.7-fold) were observed in AMD patients, when compared to control subjects. Of all the studied variables, only APP showed negative correlation with age in the AMD group. Also, positive correlations were observed for the variables Mg and Na, Cu and Mg, and P and Mg in both the AMD and control groups, whereas positive correlations were exclusively determined in the AMD group for Cu and LF, Na and Ca, and Mg and Ca. The panel constituted of MT1A, Na, and Mg predicts AMD disease in 73% of cases.

Conclusions

The different levels of target metals and (metallo-)proteins in the tear film suggest altered metal homeostasis in AMD patients. These observed pathophysiological changes may be related with the anomalous protein aggregation in the macula.

Laser and anti-vascular endothelial growth factor treatment for drusenoid pigment epithelial detachment in age-related macular degeneration: 24-month outcomes

PURPOSE

After the 12-month interim safety analysis, we investigated the 24-month primary endpoint outcomes of drusenoid pigment epithelial detachment (dPED) after laser and intravitreal anti-VEGF treatment.

METHODS

Twenty-one patients with treatment-naïve bilateral intermediate AMD with dPED and visual acuity ≤ 83 letters (Snellen 20/23) were enrolled. The subject eye received low-energy PASCAL® laser (532 nm) treatment, and the fellow eye was used as the control. Intravitreal injections were administered at 3-month intervals from baseline to 12 months. Treatment outcomes, safety and development of advanced AMD lesions were analyzed.

RESULTS

The mean drusen area and dPED height were significantly reduced (17.3 ± 2.7% vs. 112.8 ± 3.1%, P < 0.001 and 11.8 ± 4.7% vs. 119.1 ± 4.6%, P < 0.001, respectively) and the mean BCVA improved (5.11 ± 1.35 vs. 0.83 ± 1.03 letters, P = 0.014) in the study eyes compared to those in the control eyes. Development of parafoveal iRORA (nGA) (67%, 12 of 18 eyes) and cRORA (GA) (22%, 4 of 18 eyes) was observed in the study eyes, whereas three cases of iRORA and cRORA in the control eyes (17%, 3 of 18 eyes; P = 0.010 and P = 0.791, respectively).

CONCLUSIONS

Laser and anti-VEGF treatment may be a potential treatment option for intermediate AMD with dPED. However, considering the relatively high rate of secondary iRORA and cRORA development, long-term follow-up is mandatory to clarify the safety and efficacy of this treatment.

Extracellular matrix dysfunction in Sorsby patient-derived retinal pigment epithelium

Sorsby Fundus Dystrophy (SFD) is a rare form of macular degeneration that is clinically similar to age-related macular degeneration (AMD), and a histologic hallmark of SFD is a thick layer of extracellular deposits beneath the retinal pigment epithelium (RPE). Previous studies of SFD patient-induced pluripotent stem cell (iPSC) derived RPE differ as to whether these cultures recapitulate this key clinical feature by forming increased drusenoid deposits. The primary purpose of this study is to examine whether SFD patient-derived iPSC-RPE form basal deposits similar to what is found in affected family member SFD globes and to determine whether SFD iPSC RPE may be more oxidatively stressed. We performed a careful comparison of iPSC RPE from three control individuals, multiple iPSC clones from two SFD patients' iPSC RPE, and post-mortem eyes of affected SFD family members. We also examined the effect of CRISPR-Cas9 gene correction of the S204C TIMP3 mutation on RPE phenotype. Finally, targeted metabolomics with liquid chromatography and mass spectrometry analysis and stable isotope-labeled metabolite analysis were performed to determine whether SFD RPE are more oxidatively stressed. We found that SFD iPSC-RPE formed significantly more sub-RPE deposits (∼6-90 μm in height) compared to control RPE at 8 weeks. These deposits were similar in composition to the thick layer of sub-RPE deposits found in SFD family member globes by immunofluorescence staining and TEM imaging. S204C TIMP3 correction by CRISPR-Cas9 gene editing in SFD iPSC RPE cells resulted in significantly reduced basal laminar and sub-RPE calcium deposits. We detected a ∼18-fold increase in TIMP3 accumulation in the extracellular matrix (ECM) of SFD RPE, and targeted metabolomics showed that intracellular 4-hydroxyproline, a major breakdown product of collagen, is significantly elevated in SFD RPE, suggesting increased ECM turnover. Finally, SFD RPE cells have decreased intracellular reduced glutathione and were found to be more vulnerable to oxidative stress. Our findings suggest that elements of SFD pathology can be demonstrated in culture which may lead to insights into disease mechanisms.

Histology and clinical imaging lifecycle of black pigment in fibrosis secondary to neovascular age-related macular degeneration

PURPOSE

Melanotic cells with large spherical melanosomes, thought to originate from retinal pigment epithelium (RPE), are found in eyes with neovascular age-related macular degeneration (nvAMD). To generate hypotheses about RPE participation in fibrosis, we correlate histology to clinical imaging in an eye with prominent black pigment in fibrotic scar secondary to nvAMD.

METHODS

Macular findings in a white woman with untreated inactive subretinal fibrosis due to nvAMD in her right eye were documented over 9 years with color fundus photography (CFP), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT). After death (age 90 years), this index eye was prepared for light and electron microscopy to analyze 7 discrete zones of pigmentation in the fibrotic scar. In additional donor eyes with nvAMD, we determined the frequency of black pigment (n = 36 eyes) and immuno-labeled for retinoid, immunologic, and microglial markers (RPE65, CD68, Iba1, TMEM119; n = 3 eyes).

RESULTS

During follow-up of the index eye, black pigment appeared and expanded within a hypoautofluorescent fibrotic scar. The blackest areas correlated to melanotic cells (containing large spherical melanosomes), some in multiple layers. Pale areas had sparse pigmented cells. Gray areas correlated to cells with RPE organelles entombed in the scar and multinucleate cells containing sparse large spherical melanosomes. In 94% of nvAMD donor eyes, hyperpigmentation was visible. Certain melanotic cells expressed some RPE65 and mostly CD68. Iba1 and TMEM119 immunoreactivity, found both in retina and scar, did not co-localize with melanotic cells.

CONCLUSION

Hyperpigmentation in CFP results from both organelle content and optical superimposition effects. Black fundus pigment in nvAMD is common and corresponds to cells containing numerous large spherical melanosomes and superimposition of cells containing sparse large melanosomes, respectively. Melanotic cells are molecularly distinct from RPE, consistent with a process of transdifferentiation. The subcellular source of spherical melanosomes remains to be determined. Detailed histology of nvAMD eyes will inform future studies using technologies for spatially resolved molecular discovery to generate new therapies for fibrosis. The potential of black pigment as a biomarker for fibrosis can be investigated in clinical multimodal imaging datasets.

Osteopontin accumulates in basal deposits of human eyes with age-related macular degeneration and may serve as a biomarker of aging

A common clinical phenotype of several neurodegenerative and systemic disorders including Alzheimer's disease and atherosclerosis is the abnormal accumulation of extracellular material, which interferes with routine cellular functions. Similarly, patients with age-related macular degeneration (AMD), the leading cause of vision loss among the aged population, present with extracellular lipid- and protein-filled basal deposits in the back of the eye. While the exact mechanism of growth and formation of these deposits is poorly understood, much has been learned from investigating their composition, providing critical insights into AMD pathogenesis, prevention, and therapeutics. We identified human osteopontin (OPN), a phosphoprotein expressed in a variety of tissues in the body, as a newly discovered component of basal deposits in AMD patients, with a distinctive punctate staining pattern. OPN expression within these lesions, which are associated with AMD disease progression, were found to co-localize with abnormal calcium deposition. Additionally, OPN puncta colocalized with an AMD risk-associated complement pathway protein, but not with apolipoprotein E or vitronectin, two other well-established basal deposit components. Mechanistically, we found that retinal pigment epithelial cells, cells vulnerable in AMD, will secrete OPN into the extracellular space, under oxidative stress conditions, supporting OPN biosynthesis locally within the outer retina. Finally, we report that OPN levels in plasma of aged (non-AMD) human donors were significantly higher than levels in young (non-AMD) donors, but were not significantly different from donors with the different clinical subtypes of AMD. Collectively, our study defines the expression pattern of OPN in the posterior pole as a function of disease, and its local expression as a potential histopathologic biomarker of AMD.

Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life

The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.

Retinal Progression Biomarkers of Early and Intermediate Age-Related Macular Degeneration

Early and intermediate AMD patients represent a heterogeneous population with an important but variable risk of progression to more advanced stages of the disease. The five-year progression from early and intermediate AMD to late disease is known to range from 0.4% to 53%. This wide variation explains the particular interest in searching predictive AMD biomarkers. Clinical parameters such as drusen size, presence of pigmentary abnormalities, and fellow eye status were, traditionally, the more important predictive elements. Multimodal retinal assessment (Color Fundus Photography, Optical Coherence Tomography, Optical Coherence Angiography and Fundus Autofluorescence) is providing new and accurate image biomarkers, useful in research and in daily practice. If individual progression risk could be anticipated, then management plans should be adapted accordingly, considering follow-up intervals and therapeutic interventions. Here, we reviewed the most important image progression biomarkers of early and intermediate AMD with relevant interest in clinical practice.

Epithelial phenotype restoring drugs suppress macular degeneration phenotypes in an iPSC model

Age-related Macular Degeneration (AMD), a blinding eye disease, is characterized by pathological protein- and lipid-rich drusen deposits underneath the retinal pigment epithelium (RPE) and atrophy of the RPE monolayer in advanced disease stages - leading to photoreceptor cell death and vision loss. Currently, there are no drugs that stop drusen formation or RPE atrophy in AMD. Here we provide an iPSC-RPE AMD model that recapitulates drusen and RPE atrophy. Drusen deposition is dependent on AMD-risk-allele CFH(H/H) and anaphylatoxin triggered alternate complement signaling via the activation of NF-κB and downregulation of autophagy pathways. Through high-throughput screening we identify two drugs, L-745,870, a dopamine receptor antagonist, and aminocaproic acid, a protease inhibitor that reduce drusen deposits and restore RPE epithelial phenotype in anaphylatoxin challenged iPSC-RPE with or without the CFH(H/H) genotype. This comprehensive iPSC-RPE model replicates key AMD phenotypes, provides molecular insight into the role of CFH(H/H) risk-allele in AMD, and discovers two candidate drugs to treat AMD.

Hyporeflective Cores within Drusen: Association with Progression of Age-Related Macular Degeneration and Impact on Visual Sensitivity

PURPOSE

To examine the association between hyporeflective cores within drusen (HCD) and disease progression in age-related macular degeneration (AMD) and with visual function.

DESIGN

Longitudinal observational study.

PARTICIPANTS

280 eyes from 140 participants with bilateral large drusen, without late AMD.

METHODS

Multimodal imaging (MMI) and microperimetry were performed at baseline, and then every 6 months for up to 3 years. Baseline optical coherence tomography (OCT) scans were graded for the presence of HCD and used to calculate drusen volume. The total area of the drusenoid lesions containing hyporeflective cores (HCD extent) on color fundus photographs (CFPs) was calculated. CFPs were also graded for the presence of pigmentary abnormalities. The association between HCD extent with progression to late AMD (including OCT signs of atrophy) and visual sensitivity measured by microperimetry at baseline and its rate of change over time was evaluated, with and without adjustment for confounders of drusen volume, pigmentary abnormalities, and age.

MAIN OUTCOME MEASURES

Time to develop late AMD and visual sensitivity.

RESULTS

Twenty (7%) eyes from 12 (9%) individuals were found to have HCD at baseline, which was associated with a non-significantly increased rate of progression to late AMD (unadjusted P = 0.050). HCD extent was significantly associated with an increased rate of progression to late AMD (unadjusted P = 0.034) and lower visual sensitivity at baseline (unadjusted P < 0.001). However, these associations were no longer significant (P ≥ 0.264 for both) after adjusting for known risk factors for AMD progression. HCD extent was also not associated with a faster rate of visual sensitivity decline prior to the development of late AMD, with or without adjustment (P ≥ 0.674 for both). Increasing age and larger drusen volume was associated with HCD extent (P ≤ 0.041).

CONCLUSIONS

In a cohort with bilateral large drusen, HCD presence and extent was not independently associated with an increased rate of progression to late AMD over 3 years, nor with lower visual sensitivity or an increased rate of visual sensitivity decline prior to the development of late AMD, after adjusting for known risk factors of disease progression.

Low-Reflectivity Drusen With Overlying RPE Damage Revealed by Spectral-Domain OCT: Hint for the Development of Age-Related Macular Degeneration

Purpose: To observe the relationship between the characteristic changes in the drusen morphology revealed by the spectral-domain optical coherence tomography (SD-OCT) and the progression of age-related macular degeneration (AMD).

Methods: A total of 380 drusen in 45 eyes in 35 patients with the intermediate drusen were longitudinally followed up every 6 months by SD-OCT for a period of 24 months. The drusen were divided into the dynamic group and stable group according to the following parameters: number, volume, concurrent retinal pigment epithelium (RPE)/ellipsoid zone (EZ) damage, and the development of advanced AMD. The morphological characteristics of the progressive or stable drusen were further analyzed. Odds ratios (ORs) and the risk for the drusen progression were calculated.

Results: The level of interobserver and intraobserver agreement for each drusen tomographic morphological parameters ranged from 82.7 to 90%. At the end of an average follow-up of 15.92 ± 6.99 months, six patients developed choroidal neovascularization and no patients developed geographic atrophy. Finally, 139 drusen changed and 241 drusen remained stable. The drusen with low reflectivity (p < 0.001; OR: 5.26; 95% CI: 2.24–12.36), non-homogeneity without a core (p < 0.001; OR: 4.31; 95% CI: 2.08–8.92), RPE damage (p < 0.001; OR: 28.12; 95% CI: 9.43–83.85), and the EZ damage (p < 0.001; OR: 14.01; 95% CI: 5.28–37.18) were significantly associated with active change; the drusen with low reflectivity (p = 0.01; OR: 2.95; 95% CI: 1.29–6.75) and decreased overlying RPE reflectivity (p < 0.001; OR: 21.67; 95% CI: 9.20–51.02) were the independent predictors for progression. The drusen with high reflectivity were significantly associated with stabilization (p = 0.03; OR: 0.17; 95% CI: 0.04–0.84).

Conclusion: Spectral-domain optical coherence tomography is an optimized, accurate, and efficient method to follow-up the drusen. The intermediate non-exudative AMD prognosis of the patient was most strongly correlated with the drusen reflectivity and disruption of the overlying RPE layer. The drusen with low reflectivity and overlying RPE damage were more likely to progress and required frequent follow-up.