Early drusen formation in the normal and aging eye and their relation to age related maculopathy: a clinicopathological study

Accelerated Brain Atrophy, Microstructural Decline and Connectopathy in Age-Related Macular Degeneration

Age-related macular degeneration (AMD) has recently been linked to cognitive impairment. We hypothesized that AMD modifies the brain aging trajectory, and we conducted a longitudinal diffusion MRI study on 40 participants (20 with AMD and 20 controls) to reveal the location, extent, and dynamics of AMD-related brain changes. Voxel-based analyses at the first visit identified reduced volume in AMD participants in the cuneate gyrus, associated with vision, and the temporal and bilateral cingulate gyrus, linked to higher cognition and memory. The second visit occurred 2 years after the first and revealed that AMD participants had reduced cingulate and superior frontal gyrus volumes, as well as lower fractional anisotropy (FA) for the bilateral occipital lobe, including the visual and the superior frontal cortex. We detected faster rates of volume and FA reduction in AMD participants in the left temporal cortex. We identified inter-lingual and lingual-cerebellar connections as important differentiators in AMD participants. Bundle analyses revealed that the lingual gyrus had a lower streamline length in the AMD participants at the first visit, indicating a connection between retinal and brain health. FA differences in select inter-lingual and lingual cerebellar bundles at the second visit showed downstream effects of vision loss. Our analyses revealed widespread changes in AMD participants, beyond brain networks directly involved in vision processing.

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.

Retromode Imaging Technology for Detecting Drusen-Like Deposits in Healthy Adults

PURPOSE

To investigate the ability of retromode imaging technology to visualize drusen-like deposits (DLDs) in the macular region of healthy individuals without retinal diseases. Additionally, the correlation between subject age and the density of DLDs was assessed and their topographic distribution was evaluated.

DESIGN

Prospective, observational, cross-sectional study SUBJECTS: Healthy volunteers (aged ≥ 35 years) without macular diseases.

METHODS

This study evaluated macular images in healthy adults using color fundus photography (FP) and retromode imaging. Two masked graders counted the number of DLDs identifiable with each modality. The standardized ETDRS concentric rings were adopted to divide DLDs based on their topographic distribution.

MAIN OUTCOME MEASURES

Comparison of the number of DLDs detected with each imaging modality. The association between DLDs and age. The topographic distribution of macular DLDs with retromode imaging.

RESULTS

The study included 91 eyes of 52 healthy volunteers (mean ± standard deviation age, 57.9 ± 10.9 years; range, 36-82 years). Overall, at least 1 DLD was present in 63.74% of eyes on color FP and 96.71% on retromode. Retromode imaging allowed detection of significantly more DLDs compared with color FP within the ETDRS grid (median [interquartile range], 4 [1-14] vs. 0 [0-0] respectively; P < 0.001). The density of DLDs was higher in the outer and inner rings compared with the central subfield (relative risk [RR], 16.70; 95% confidence interval [CI], 10.3-27.3 vs. RR 17.1; 95% CI, 10.5-27.6, respectively). Age was significantly correlated with DLDs density in all 3 sectors (all P < 0.05).

CONCLUSIONS

Retromode technology allowed the detection of a significantly higher number of DLDs compared with FP in the macula of healthy individuals. This noninvasive imaging modality could be used to investigate the effect of the aging process on the macula, fostering a better understanding of the pathophysiology of age-related macular diseases.

FINANCIAL DISCLOSURE(S)

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

Multimodal Imaging of Reticular Pseudodrusen in Turkish Patients

Objectives

To investigate the presence and prevalence of reticular pseudodrusen (RPD) in patients with age-related macular degeneration using multiple imaging modalities and to compare the sensitivity and specificity of these modalities in the detection of RPD.

Materials and Methods

Images from a total of 198 consecutive patients were analyzed prospectively. Color fundus photography, red-free imaging, spectral domain optical coherence tomography (SD-OCT), infrared and blue reflectance (BR) imaging, fundus autofluorescence (FAF), enhanced-depth imaging OCT (EDI-OCT), fundus fluorescein angiography (FFA) and indocyanine green angiography were performed. RPD was diagnosed in the presence of relevant findings in at least two of the imaging methods used.

Results

RPD were detected in 149 eyes (37.6%). In the detection of RPD, color fundus photography, red-free photography, SD-OCT, infrared, FAF, BR, and FFA imaging had sensitivity values of 50%, 57.7%, 91.6%, 95%, 74.6%, 65.7%, and 28.2% and specificity values of 99.6%, 100%, 98.4%, 94.6%, 100%, 99.6%, and 69.8%, respectively.

Conclusion

Infrared imaging had the highest sensitivity. SD-OCT combined with infrared imaging was the most sensitive imaging technique for detecting RPD. The high specificity of FAF, red-free, and BR imaging may be useful to confirm a diagnosis of RPD.

HISTOLOGY, DIMENSIONS, AND FLUORESCEIN STAINING CHARACTERISTICS OF NODULAR AND CUTICULAR DRUSEN IN AGE-RELATED MACULAR DEGENERATION

PURPOSE

To enable in vivo analysis of drusen composition and lifecycle, the macular nodular and cuticular drusen were assessed using histology.

METHODS

Median and interquartile range of base widths of single (nonconfluent) nodular drusen in three sources were determined histologically: 43 eyes of 43 clinically undocumented donors, in an online resource; one eye with punctate hyperfluorescence in fluorescein angiography; and two eyes of one patient with bilateral "starry sky" cuticular drusen. All tissues were processed for high-resolution epoxy-resin histology and for cuticular drusen, transmission electron microscopy.

RESULTS

All drusen localized between the retinal pigment epithelium basal lamina and inner collagenous layer of the Bruch membrane. They were solid, globular, homogeneously stained with toluidine blue, and uncovered by basal laminar deposit and basal mounds. Median base widths were 13.0 µ m (Source 1, N = 128 drusen, interquartile range 7.7, 20.0 µ m), 15.3 µ m (Source 2, N = 87, interquartile range 10.6, 20.5 µ m), and 7.3 µ m (Source 3, N = 78, interquartile range 3.9, 14.1 µ m).

CONCLUSION

In three samples, >90% of solitary nodular drusen were <30 µ m, the visibility threshold in color fundus photography; these drusen are hyperfluorescent in fluorescein angiography. Whether these progress to soft drusen, known as high-risk from epidemiology studies and hypofluorescent, may be determinable from multimodal imaging datasets that include fluorescein angiography.

Cataract, Cataract Surgery, and Risk of Incident Dementia: A Prospective Cohort Study of 300,823 Participants

BACKGROUND

Visual impairment and interventions to preserve vision may impact dementia risk. Thus, we aimed to explore the associations of cataract and cataract surgery with the risk of dementia.

METHODS

Prospective data from 300,823 individuals in the UK Biobank were used. We used multivariate Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals for associations, with healthy control subjects as a reference. The same method was used to explore the effects of surgery on dementia outcomes of patients with cataract. One-way analysis of variance was performed to examine the associations between cataract and brain morphometric measures.

RESULTS

After a mean follow-up of 8.4 years, 3226 individuals were diagnosed with dementia. The nonsurgical cataract group had increased risk of all-cause dementia (HR, 1.214; 95% CI, 1.012-1.456; p = .037) and Alzheimer's disease (HR, 1.479; 95% CI, 1.105-1.981; p = .009). However, there was no difference in dementia risk between the cataract surgery group and the healthy control group. Cataract surgery was associated with decreased risk of all-cause dementia (HR, 0.632; 95% CI, 0.421-0.947; p = .026) and Alzheimer's disease (HR, 0.399; 95% CI, 0.196-0.812; p = .011) compared with the nonsurgical group. Additionally, cataract was negatively associated with cortical volumes, aging-related subcortical volumes, and fractional anisotropy of white matter fibers.

CONCLUSIONS

Cataract patients who did not receive surgical treatment had an increased risk of dementia. However, cataract surgery could reverse the risk of dementia. Our findings on brain structures and pathways in patients with cataract also provided evidence for the mechanism. Reversible visual impairment, such as cataract, is a promising modifiable risk factor for dementia.

A Protocol to Evaluate and Quantify Retinal Pigmented Epithelium Pathologies in Mouse Models of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a debilitating retinal disorder in aging populations. It is widely believed that dysfunction of the retinal pigmented epithelium (RPE) is a key pathobiological event in AMD. To understand the mechanisms that lead to RPE dysfunction, mouse models can be utilized by researchers. It has been established by previous studies that mice can develop RPE pathologies, some of which are observed in the eyes of individuals diagnosed with AMD. Here, we describe a phenotyping protocol to assess RPE pathologies in mice. This protocol includes the preparation and evaluation of retinal cross-sections using light microscopy and transmission electron microscopy, as well as that of RPE flat mounts by confocal microscopy. We detail the common types of murine RPE pathologies observed by these techniques and ways to quantify them through unbiased methods for statistical testing. As proof of concept, we use this RPE phenotyping protocol to quantify the RPE pathologies observed in mice overexpressing transmembrane protein 135 (Tmem135) and aged wild-type C57BL/6J mice. The main goal of this protocol is to present standard RPE phenotyping methods with unbiased quantitative assessments for scientists using mouse models of AMD.

Small hard drusen and associated factors in early seniority

PURPOSE

The purpose of this study was to examine the ocular and systemic risk profile of the fundus phenotype ≥ 20 small hard (macular) drusen (< 63 μm in diameter).

METHODS

This single-center, cross-sectional study of 176 same-sex twin pairs aged 30 to 80 (median 60) years was a component of a framework study of the transition from not having age-related macular degeneration to having early AMD. Drusen categories assessed using fundus photography and optical coherence tomography included small hard drusen (diameter < 63 μm), intermediate soft drusen (63-125 μm), and large soft drusen (> 125 μm), of which the soft drusen are compatible with a diagnosis of AMD.

RESULTS

Having ≥ 20 small hard drusen within or outside the macula was associated with increasing age, lower body mass index, shorter axial length, hyperopia, female sex, increasing high-density lipoprotein (HDL), high alcohol consumption, and with the presence of soft drusen.

CONCLUSIONS

Having ≥ 20 small hard drusen was associated with some AMD-related risk factors, but not with smoking, increasing body mass index, and higher blood pressure. Having ≥ 20 small hard drusen was also associated with soft drusen, in agreement with previous studies. These findings suggest that small hard drusen are not an early manifestation of AMD but the product of a distinct process of tissue alteration that promotes the development of AMD or some subtype thereof.

Heritability of retinal drusen in the Copenhagen Twin Cohort Eye Study

PURPOSE

To study age- and sex-adjusted heritability of small hard drusen and early age-related macular degeneration (AMD) in a population-based twin cohort.

METHODS

This was a single-centre, cross-sectional, classical twin study with ophthalmic examination including refraction, biometry, best-corrected visual acuity assessment, colour and autofluorescence fundus photography, and fundus optical coherence tomography. Grading and categorization of drusen was by diameter and location.

RESULTS

The study enrolled 176 same-sex pairs of twins of mean (SD) age 58.6 (9.9) years. The prevalence of the four phenotypes ≥20 small hard macular drusen (largest diameter < 63 μm), ≥20 small hard extramacular drusen, intermediate drusen (63-125 μm) anywhere, and large drusen (>125 μm) anywhere was 12.4%, 36.4%, 5.8%, and 8.4%, respectively, and the respective heritabilities, adjusted for age and sex, were 78.2% [73.5-82.9], 69.1% [62.3-75.9], 30.1% [4.1-56.1], and 65.6% [26.4-100]. Age trajectory analysis supported a gradual transition to larger numbers of small hard drusen with increasing age. The heritability of ≥20 small hard drusen was markedly lower than the 99% found in the 40% overlapping twin cohort that was seen 20 years earlier.

CONCLUSION

Numerous (≥20) small hard drusen and larger drusen that fit the definition of dry AMD were highly heritable. Small hard drusen counts increased with age. Decreasing heritability with increasing age suggests that the impact of behavioural and environmental factors on the development of small hard drusen increases with age.

Retinal pigment epithelium extracellular vesicles are potent inducers of age-related macular degeneration disease phenotype in the outer retina

Age-related macular degeneration (AMD) is a leading cause of blindness. Vision loss is caused by the retinal pigment epithelium (RPE) and photoreceptors atrophy and/or retinal and choroidal angiogenesis. Here we use AMD patient-specific RPE cells with the Complement Factor H Y402H high-risk polymorphism to perform a comprehensive analysis of extracellular vesicles (EVs), their cargo and role in disease pathology. We show that AMD RPE is characterised by enhanced polarised EV secretion. Multi-omics analyses demonstrate that AMD RPE EVs carry RNA, proteins and lipids, which mediate key AMD features including oxidative stress, cytoskeletal dysfunction, angiogenesis and drusen accumulation. Moreover, AMD RPE EVs induce amyloid fibril formation, revealing their role in drusen formation. We demonstrate that exposure of control RPE to AMD RPE apical EVs leads to the acquisition of AMD features such as stress vacuoles, cytoskeletal destabilization and abnormalities in the morphology of the nucleus. Retinal organoid treatment with apical AMD RPE EVs leads to disrupted neuroepithelium and the appearance of cytoprotective alpha B crystallin immunopositive cells, with some co-expressing retinal progenitor cell markers Pax6/Vsx2, suggesting injury-induced regenerative pathways activation. These findings indicate that AMD RPE EVs are potent inducers of AMD phenotype in the neighbouring RPE and retinal cells.

Does the Outer Retinal Thickness Around Geographic Atrophy Represent Another Clinical Biomarker for Predicting Growth?

PURPOSE

To determine whether the outer retinal layer (ORL) thickness around geographic atrophy (GA) could serve as a clinical biomarker to predict the annual enlargement rate (ER) of GA.

DESIGN

Retrospective analysis of a prospective, observational case series.

METHODS

Eyes with GA were imaged with a swept-source OCT 6 × 6 mm scan pattern. GA lesions were measured from customized en face OCT images and the annual ERs were calculated. The ORL was defined and segmented from the inner boundary of outer plexiform layer (OPL) to the inner boundary of retinal pigment epithelium (RPE) layer. The ORL thickness was measured at different subregions around GA.

RESULTS

A total of 38 eyes from 27 participants were included. The same eyes were used for the choriocapillaris (CC) flow deficit (FD) analysis and the RPE to the Bruch membrane (RPE-BM) distance measurements. A negative correlation was observed between the ORL thickness and the GA growth. The ORL thickness in a 300-μm rim around GA showed the strongest correlation with the GA growth (r = -0.457, P = .004). No correlations were found between the ORL thickness and the CC FDs; however, a significant correlation was found between the ORL thickness and the RPE-BM distances around GA (r = -0.398, P = .013).

CONCLUSIONS

ORL thickness showed a significant negative correlation with annual GA growth, but also showed a significant correlation with the RPE-BM distances, suggesting that they were dependently correlated with GA growth. This finding suggests that the loss of photoreceptors was associated with the formation of basal laminar deposits around GA.

Exploring the pathogenesis of age-related macular degeneration: A review of the interplay between retinal pigment epithelium dysfunction and the innate immune system

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in the older population. Classical hallmarks of early and intermediate AMD are accumulation of drusen, a waste deposit formed under the retina, and pigmentary abnormalities in the retinal pigment epithelium (RPE). When the disease progresses into late AMD, vision is affected due to death of the RPE and the light-sensitive photoreceptors. The RPE is essential to the health of the retina as it forms the outer blood retinal barrier, which establishes ocular immune regulation, and provides support for the photoreceptors. Due to its unique anatomical position, the RPE can communicate with the retinal environment and the systemic immune environment. In AMD, RPE dysfunction and the accumulation of drusen drive the infiltration of retinal and systemic innate immune cells into the outer retina. While recruited endogenous or systemic mononuclear phagocytes (MPs) contribute to the removal of noxious debris, the accumulation of MPs can also result in chronic inflammation and contribute to AMD progression. In addition, direct communication and indirect molecular signaling between MPs and the RPE may promote RPE cell death, choroidal neovascularization and fibrotic scarring that occur in late AMD. In this review, we explore how the RPE and innate immune cells maintain retinal homeostasis, and detail how RPE dysfunction and aberrant immune cell recruitment contribute to AMD pathogenesis. Evidence from AMD patients will be discussed in conjunction with data from preclinical models, to shed light on future therapeutic targets for the treatment of AMD.

Choroidal Vasculature Changes in Age-Related Macular Degeneration: From a Molecular to a Clinical Perspective

The contribution of choroidal vasculature to the pathogenesis of age-related macular degeneration (AMD) has been long debated. The present narrative review aims to discuss the primary molecular and choroidal structural changes occurring with aging and AMD with a brief overview of the principal multimodal imaging modalities and techniques that enable the optimal in vivo visualization of choroidal modifications. The molecular aspects that target the choroid in AMD mainly involve human leukocyte antigen (HLA) expression, complement dysregulation, leukocyte interaction at Bruch’s membrane, and mast cell infiltration of the choroid. A mechanistic link between high-risk genetic loci for AMD and mast cell recruitment has also been recently demonstrated. Recent advances in multimodal imaging allow more detailed visualization of choroidal structure, identifying alterations that may expand our comprehension of aging and AMD development.

Visualizing lipid behind the retina in aging and age-related macular degeneration, via indocyanine green angiography (ASHS-LIA)

Age-related macular degeneration (AMD) causes legal blindness in older adults worldwide. Soft drusen are the most extensively documented intraocular risk factor for progression to advanced AMD. A long-standing paradox in AMD pathophysiology has been the vulnerability of Asian populations to polypoidal choroidal vasculopathy (PCV) in the presence of relatively few drusen. Age-related scattered hypofluorescent spots on late phase indocyanine green angiography (ASHS-LIA) was recently proposed as precursors of PCV. Herein, we offer a resolution to the paradox by reviewing evidence that ASHS-LIA indicates the diffuse form of lipoprotein-related lipids accumulating in Bruch's membrane (BrM) throughout adulthood. Deposition of these lipids leads to soft drusen and basal linear deposit (BLinD), a thin layer of soft drusen material in AMD; Pre-BLinD is the precursor. This evidence includes: 1. Both ASHS-LIA and pre-BLinD/BLinD accumulate in older adults and start under the macula; 2. ASHS-LIA shares hypofluorescence with soft drusen, known to be physically continuous with pre-BLinD/BLinD. 3. Model system studies illuminated a mechanism for indocyanine green uptake by retinal pigment epithelium. 4. Neither ASHS-LIA nor pre-BLinD/ BLinD are visible by multimodal imaging anchored on current optical coherence tomography, as confirmed with direct clinicopathologic correlation. To contextualize ASHS-LIA, we also summarize angiographic characteristics of different drusen subtypes in AMD. As possible precursors for PCV, lipid accumulation in forms beyond soft drusen may contribute to the pathogenesis of this prevalent disease in Asia. ASHS-LIA also might help identify patients at risk for progression, of value to clinical trials for therapies targeting early or intermediate AMD.

Microbiota mitochondria disorders as hubs for early age-related macular degeneration

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease affecting the central area (macula lutea) of the retina. Research on the pathogenic mechanism of AMD showed complex cellular contribution governed by such risk factors as aging, genetic predisposition, diet, and lifestyle. Recent studies suggested that microbiota is a transducer and a modifier of risk factors for neurodegenerative diseases, and mitochondria may be one of the intracellular targets of microbial signaling molecules. This review explores studies supporting a new concept on the contribution of microbiota-mitochondria disorders to AMD. We discuss metabolic, vascular, immune, and neuronal mechanism in AMD as well as key alterations of photoreceptor cells, retinal pigment epithelium (RPE), Bruch's membrane, choriocapillaris endothelial, immune, and neuronal cells. Special attention was paid to alterations of mitochondria contact sites (MCSs), an organelle network of mitochondria, endoplasmic reticulum, lipid droplets (LDs), and peroxisomes being documented based on our own electron microscopic findings from surgically removed human eyes. Morphometry of Bruch's membrane lipids and proteoglycans has also been performed in early AMD and aged controls. Microbial metabolites (short-chain fatty acids, polyphenols, and secondary bile acids) and microbial compounds (lipopolysaccharide, peptidoglycan, and bacterial DNA)-now called postbiotics-in addition to local effects on resident microbiota and mucous membrane, regulate systemic metabolic, vascular, immune, and neuronal mechanisms in normal conditions and in various common diseases. We also discuss their antioxidant, anti-inflammatory, and metabolic effects as well as experimental and clinical observations on regulating the main processes of photoreceptor renewal, mitophagy, and autophagy in early AMD. These findings support an emerging concept that microbiota-mitochondria disorders may be a crucial pathogenic mechanism of early AMD; and similarly, to other age-related neurodegenerative diseases, new treatment approaches should be targeted at these disorders.

Retinal drusen counts are increased in inflammatory bowel disease, and with longer disease duration, more complications and associated IgA glomerulonephritis

Retinal drusen are deposits of inflammatory proteins that are found in macular degeneration and glomerulonephritis and result, in part, from complement activation. This was a cross-sectional observational study of individuals with inflammatory bowel disease (IBD) recruited from a Gastroenterology clinic who underwent non-mydriatic retinal photography. Deidentified images were examined for drusen, and drusen counts and size were compared with matched controls, and examined for clinical associations. The cohort with IBD comprised 19 individuals with ulcerative colitis, 41 with Crohn's disease and three with indeterminate colitis, including 34 males (54%) and an overall median age of 48 (IQR 23) years. Their median IBD duration was 7 (IQR 10) years, median CRP level was 7 (IQR 14) mg/L, and 28 (44%) had complications (fistula, stricture, bowel resection etc.), while 28 with Crohn's disease (68%) had colonic involvement. Drusen counts were higher in IBD than controls (12 ± 34, 3 ± 8 respectively, p = 0.04). Counts ≥ 10 were also more common (14, 22%, and 4, 6%, p = 0.02, OR 4.21, 95%CI 1.30 to 13.63), and associated with longer disease duration (p = 0.01, OR 1.06, 95%CI 1.00 to 1.13), an increased likelihood of complications (p = 0.003, OR 6.90, 95%CI 1.69 to 28.15) and higher CRP levels at recruitment (p = 0.008, OR1.02, 95%CI 1.00 to 1.05). Increased retinal drusen were found in all four individuals with Crohn's disease and IgA glomerulonephritis. IBD and drusen may share pathogenetic mechanisms and underlying risk factors such as complement activation.

Photoreceptor Layer Thinning Is an Early Biomarker for Age-Related Macular Degeneration: Epidemiologic and Genetic Evidence from UK Biobank OCT Data

PURPOSE

Despite widespread use of OCT, an early-stage imaging biomarker for age-related macular degeneration (AMD) has not been identified. Pathophysiologically, the timing of drusen accumulation in relationship to photoreceptor degeneration in AMD remains unclear, as are the inherited genetic variants contributing to these processes. Herein, we jointly analyzed OCT, electronic health record data, and genomic data to characterize the time sequence of changes in retinal layer thicknesses in AMD, as well as epidemiologic and genetic associations between retinal layer thicknesses and AMD.

DESIGN

Cohort study.

PARTICIPANTS

Forty-four thousand eight hundred twenty-three individuals from the UK Biobank (enrollment age range, 40-70 years; 54% women; median follow-up, 10 years).

METHODS

The Topcon Advanced Boundary Segmentation algorithm was used for retinal layer segmentation. We associated 9 retinal layer thicknesses with prevalent AMD (present at enrollment) in a logistic regression model and with incident AMD (diagnosed after enrollment) in a Cox proportional hazards model. Next, we associated AMD-associated genetic alleles, individually and as a polygenic risk score (PRS), with retinal layer thicknesses. All analyses were adjusted for age, age-squared (age2), sex, smoking status, and principal components of ancestry.

MAIN OUTCOME MEASURES

Prevalent and incident AMD.

RESULTS

Photoreceptor segment (PS) thinning was observed throughout the lifespan of individuals analyzed, whereas retinal pigment epithelium (RPE) and Bruch's membrane (BM) complex thickening started after 57 years of age. Each standard deviation (SD) of PS thinning and RPE-BM complex thickening was associated with incident AMD (PS: hazard ratio [HR], 1.35; 95% confidence interval [CI], 1.23-1.47; P = 3.7 × 10-11; RPE-BM complex: HR, 1.14; 95% CI, 1.06-1.22; P = 0.00024). The AMD PRS was associated with PS thinning (β, -0.21 SD per twofold genetically increased risk of AMD; 95% CI, -0.23 to -0.19; P = 2.8 × 10-74), and its association with RPE-BM complex was U-shaped (thinning with AMD PRS less than the 92nd percentile and thickening with AMD PRS more than the 92nd percentile). The loci with strongest support for genetic correlation were AMD risk-raising variants Complement Factor H (CFH):rs570618-T, CFH:rs10922109-C, and Age-Related Maculopathy Susceptibility 2 (ARMS2)/High-Temperature Requirement Serine Protease 1 (HTRA1):rs3750846-C on PS thinning and SYN3/Tissue Inhibitor of Metalloprotease 3 (TIMP3):rs5754227-T on RPE-BM complex thickening.

CONCLUSIONS

Epidemiologically, PS thinning precedes RPE-BM complex thickening by decades and is the retinal layer most strongly predictive of future AMD risk. Genetically, AMD risk variants are associated with decreased PS thickness. Overall, these findings support PS thinning as an early-stage biomarker for future AMD development.

Retinal drusen in glomerulonephritis with or without immune deposits suggest systemic complement activation in disease pathogenesis

Retinal drusen are characteristic of macular degeneration and complement activation, but also occur in C3, lupus and IgA nephropathy. This cross-sectional observational study compared drusen counts in different forms of glomerulonephritis. Consecutive individuals with glomerulonephritis attending a general renal or transplant clinic underwent retinal imaging with a non-mydriatic camera. Drusen were counted in deidentified images by trained graders, compared with matched hospital patients, and correlated with clinical features. Eighty-four individuals with glomerulonephritis had a mean drusen count of 10 ± 27 compared with 3 ± 8 in hospital controls (p = 0.007). Fourteen individuals with glomerulonephritis (17%) and 4 hospital controls (4/49, 8%) had increased drusen counts (≥ 10) (p = 0.20). Increased drusen counts ≥ 10 were present in 13 (13/63, 21%)  of those with glomerulonephritis and immune deposits [membranous (n = 8), antiglomerular basement membrane nephritis (n = 6), FSGS (n = 49)], and one of the 21 (5%) with glomerulonephritis without immune deposits [ANCA-associated (n = 15), minimal change disease (n = 6)]. In antibody-mediated glomerulonephritis (n = 14), mean drusen counts were 2 ± 3 in individuals with normal kidney function, 16 ± 41 with impaired function and 5 ± 7 with kidney failure . Mean counts were 24 ± 56 in individuals with glomerular IgG deposits and 1 ± 1 in those without (p = 0.76), and 23 ± 60 with complement deposits and 4 ± 8 in those without. Drusen counts were also less in immunosuppressed individuals (p = 0.049). The demonstration of retinal drusen in some forms of glomerulonephritis is consistent with systemic complement activation, and suggests that treatment targeting the complement pathways is worthwhile.

Molecular Mechanisms Underlying the Therapeutic Role of Vitamin E in Age-Related Macular Degeneration

The eye is particularly susceptible to oxidative stress and disruption of the delicate balance between oxygen-derived free radicals and antioxidants leading to many degenerative diseases. Attention has been called to all isoforms of vitamin E, with α-tocopherol being the most common form. Though similar in structure, each is diverse in antioxidant activity. Preclinical reports highlight vitamin E’s influence on cell physiology and survival through several signaling pathways by activating kinases and transcription factors relevant for uptake, transport, metabolism, and cellular action to promote neuroprotective effects. In the clinical setting, population-based studies on vitamin E supplementation have been inconsistent at times and follow-up studies are needed. Nonetheless, vitamin E’s health benefits outweigh the controversies. The goal of this review is to recognize the importance of vitamin E’s role in guarding against gradual central vision loss observed in age-related macular degeneration (AMD). The therapeutic role and molecular mechanisms of vitamin E’s function in the retina, clinical implications, and possible toxicity are collectively described in the present review.

Serum Cholesterol Efflux Capacity in Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

Purpose

To investigate serum cholesterol efflux capacity (the ability of the serum to accept cholesterol) and factors that regulate it using nuclear magnetic resonance-quantified measures of lipoprotein particle composition and size and apolipoproteins metrics in patients with age-related macular degeneration (AMD).

Design

Case-control study.

Participants

Four hundred two serum samples from 80 patients with early AMD (eAMD), and 212 patients with neovascular AMD (nAMD), including 80 with typical nAMD (tAMD) and 132 with polypoidal choroidal vasculopathy (PCV), and 110 age- and gender matched control participants.

Methods

Serum from participants showed cholesterol efflux capacity measured using in vitro cell assays and lipoprotein subfractions measured using nuclear magnetic resonance (Nightingale, Ltd). Associations between cholesterol efflux capacity (measured in percentage) and lipid subfractions were investigated in the patients and control participants.

Main Outcome Measures

Cholesterol efflux capacity and lipid subfractions in control, eAMD, and nAMD. Associations between HDL subfractions and cholesterol efflux capacity.

Results

Cholesterol efflux capacity was higher in patients with eAMD (68.0 ± 11.3% [mean ± standard deviation]) and nAMD (75.9 ± 27.7%) than in the control participants (56.9 ± 16.7%) after adjusting for age, gender, and use of lipid-lowering drug (P < 0.0001). Nuclear magnetic resonance lipidomics demonstrated that the mean diameter of HDL was larger both in eAMD (9.96 ± 0.27 mm [mean ± standard deviation]) and PCV (9.97 ± 0.23 mm) compared with that of the control participants (9.84 ± 0.24 mm; P = 0.0001 for both). Among the 28 HDL subfractions, most of the small, medium, and large HDLs, but none of the 7 extra large HDLs fractions, were associated moderately with cholesterol efflux capacity in eAMD and PCV (R = 0.149-0.277).

Conclusions

Serum cholesterol efflux capacity was increased in eAMD and PCV, but not tAMD, possibly reflecting differential underlying pathophysiologic features of lipid dysregulation in tAMD and PCV. Further studies should be directed toward investigating the diverse biological activities of HDL in AMD, including macular pigment transport, regulation of inflammation, and local cholesterol transport system.

Functional Correlates of Outer Retina Remodeling in Intermediate Age-Related Macular Degeneration Using Microperimetry

Purpose

To assess the effect of drusen morphometric changes and choroidal vascular modifications on retinal sensitivity (RS) evaluated through microperimetry in intermediate age-related macular degeneration (iAMD).

Methods

A retrospective review of 18 iAMD patients (18 eyes) with a 12-month follow-up was performed. Eye-tracked spectral-domain optical coherence tomography was obtained, with automatic segmentation of the outer retinal layer (ORL) delineating the drusen area from the external limiting membrane to Bruch's membrane and outer nuclear layer (ONL) thickness maps adjusted manually, as needed. Advanced retinal pigment epithelium analysis was also performed with a ZEISS PLEX Elite 900. Microperimetry obtained under mesopic conditions was overlaid with the corresponding thickness maps with Fiji software. The choroidal vascularity index (CVI) was calculated in the subfoveal b-scan and volumetric in the central 1-mm subfield.

Results

A reduced central ONL thickness was strongly associated with RS decline at the same region (r = 0.69, P = 0.002) and globally (r = 0.80, P < 0.001) at baseline, but also at 1 year in the central subfield (central: r = 0.70, P = 0.001). One-year subfoveal CVI variation, differently from volumetric CVI, directly influenced the central (r = 0.64, P = 0.004) and global RS (r = 0.59, P = 0.009), indicating that a CVI reduction negatively affected RS. A greater volumetric CVI within central 1-mm was associated with ORL thickening at 1 year (r = 0.61, P = 0.008).

Conclusions

Progressive degeneration of the ONL is related to irreversible photoreceptor dysfunction in iAMD. Likewise, choroidal vascular modifications are associated with a significant functional decline in the central region and diffusely.

Retinal drusen are more common and larger in SLE with renal impairment

Introduction

Complement has been implicated in systemic lupus erythematosus (SLE) pathogenesis on the basis of the associations with inherited complement defects and genome-wide association study risk alleles, glomerular deposits, reduced serum levels, and occasional reports of retinal drusen. This study examined drusen in SLE and their clinical significance.

Methods

This cross-sectional observational study compared individuals with SLE recruited from renal and rheumatology clinics with hospital controls. Participants were reviewed for clinical features and underwent imaging with a nonmydriatic retinal camera. Deidentified images were examined by 2 trained graders for drusen number and size using a grid overlay.

Results

The cohort with SLE (n = 65) comprised 55 women (85%) and 10 men (15%) with a median age of 47 years (interquartile range 35–59), where 23 (35%) were of southern European or Asian ancestry, and 32 (49%) had biopsy-proven lupus nephritis. Individuals with SLE had higher mean drusen numbers than controls (27 ± 60, 3 ± 9, respectively, P = 0.001), more drusen counts ≥10 (31, 48% and 3, 5%, respectively, P < 0.001), and more medium-large drusen (14, 22% and 3, 5%, respectively, P < 0.001). In SLE, mean drusen counts were higher, and drusen were larger, with an estimated glomerular filtration rate (eGFR) <90 ml/min per 1.73 m² (P = 0.02, P = 0.02, respectively) or class IV nephritis (P = 0.03, P = 0.02).

Conclusion

Drusen composition resembles that of glomerular immune deposits. CFH controls complement activation in the extracellular matrix and CFH risk variants are shared by drusen in macular degeneration and by SLE. CFH represents a possible treatment target for SLE especially with renal impairment.

Correlation Between Localized Choriocapillaris Perfusion and Macular Function in Eyes with Geographic Atrophy

PURPOSE

To test the hypothesis that choriocapillaris perfusion correlates with visual function in geographic atrophy (GA).

DESIGN

Cross-sectional, single-center study.

METHODS

We imaged choriocapillaris flow using 6 × 6-mm swept-source optical coherence tomography angiography scans and measured retinal sensitivity using fundus-guided microperimetry in the central 20° in 18 eyes of 12 patients with GA and 7 eyes of 4 healthy persons. Optical coherence tomography angiography scans were divided into a grid and microperimetry results were superimposed using retinal vascular landmarks. The main outcome measure correlated choriocapillaris flow deficit with retinal sensitivity at each localized region. Robust linear mixed effects regression compared flow deficit or sensitivity with distance from the fovea. The Pearson r correlation described the relationship between flow deficit or retinal sensitivity and distance from the GA border.

RESULTS

Choriocapillaris flow deficit was significantly greater in patients with GA than in healthy persons (mean ± SD: 24.2% ± 7.9% vs 7.9% ± 2.3%; P = .0015) and retinal sensitivity was significantly lower in patients with GA than in healthy persons (mean difference ± SD: -17.0 ± 1.2 dB; P < .001). In GA, choriocapillaris flow deficit decreased (r = -0.40; 95% CI: -0.54 to -0.27) and retinal sensitivity increased (r = +0.63; 95% CI: 0.30 to 0.81) with distance from the GA margin. Choriocapillaris flow deficits inversely correlated with retinal sensitivity (r = -0.61; 95% CI: -0.75 to -0.42).

CONCLUSIONS

Choriocapillaris flow and retinal sensitivity improved with distance from the GA margin. Choriocapillaris flow deficit was inversely correlated with sensitivity, supporting the hypothesis that choriocapillaris perfusion correlated with macular function.

Autofluorescent Organelles Within the Retinal Pigment Epithelium in Human Donor Eyes With and Without Age-Related Macular Degeneration

Purpose

Human retinal pigment epithelium (RPE) cells contain lipofuscin, melanolipofuscin, and melanosome organelles that impact clinical autofluorescence (AF) imaging. Here, we quantified the effect of age-related macular degeneration (AMD) on granule count and histologic AF of RPE cell bodies.

Methods

Seven AMD-affected human RPE-Bruch's membrane flatmounts (early and intermediate = 3, late dry = 1, and neovascular = 3) were imaged at fovea, perifovea, and near periphery using structured illumination and confocal AF microscopy (excitation 488 nm) and compared to RPE-flatmounts with unremarkable macula (n = 7, >80 years). Subsequently, granules were marked with computer assistance, and classified by their AF properties. The AF/cell was calculated from confocal images. The total number of granules and AF/cell was analyzed implementing a mixed effect analysis of covariance (ANCOVA).

Results

A total of 152 AMD-affected RPE cells were analyzed (fovea = 22, perifovea = 60, and near-periphery = 70). AMD-affected RPE cells showed increased variability in size and a significantly increased granule load independent of the retinal location (fovea: P = 0.02, perifovea: P = 0.04, and near periphery: P < 0.01). The lipofuscin fraction of total organelles decreased and the melanolipofuscin fraction increased in AMD, at all locations (especially the fovea). AF was significantly lower in AMD-affected cells (fovea: <0.01, perifovea: <0.01, and near periphery: 0.02).

Conclusions

In AMD RPE, lipofuscin was proportionately lowest in the fovea, a location also known to be affected by accumulation of soft drusen and preservation of cone-mediated visual acuity. Enlarged RPE cell bodies displayed increased net granule count but diminished total AF. Future studies should also assess the impact on AF imaging of RPE apical processes containing melanosomes.

The Role of Inflammation in Retinal Neurodegeneration and Degenerative Diseases

Retinal neurodegeneration is predominantly reported as the apoptosis or impaired function of the photoreceptors. Retinal degeneration is a major causative factor of irreversible vision loss leading to blindness. In recent years, retinal degenerative diseases have been investigated and many genes and genetic defects have been elucidated by many of the causative factors. An enormous amount of research has been performed to determine the pathogenesis of retinal degenerative conditions and to formulate the treatment modalities that are the critical requirements in this current scenario. Encouraging results have been obtained using gene therapy. We provide a narrative review of the various studies performed to date on the role of inflammation in human retinal degenerative diseases such as age-related macular degeneration, inherited retinal dystrophies, retinitis pigmentosa, Stargardt macular dystrophy, and Leber congenital amaurosis. In addition, we have highlighted the pivotal role of various inflammatory mechanisms in the progress of retinal degeneration. This review also offers an assessment of various therapeutic approaches, including gene-therapies and stem-cell-based therapies, for degenerative retinal diseases.

A New Method for Visualizing Drusen and Their Progression in Flood-Illumination Adaptive Optics Ophthalmoscopy

Purpose

Drusen are dynamic sub-RPE deposits that are risk factors for late-stage age-related macular degeneration (AMD). Here we show a new imaging method using flood-illumination adaptive optics (FIAO) that reveal drusen with high contrast and resolution.

Methods

A fovea-centered 4° × 4° FIAO image and eight surrounding images with gaze displaced by ±2° vertically and horizontally were acquired. Clinical color fundus and spectral-domain optical coherence tomography were acquired for clinical grading and comparison. Custom software registered overlapping FIAO images and fused the data statistically to generate a fovea-centered 4° × 4° gaze-dependent image. Our dataset included 15 controls (aged 31-72) and 182 eyes from 104 AMD patients (aged 56-92), graded as either normal aging (n = 7), and early (n = 12), intermediate (n = 108) and late AMD (n = 42); 27 had subretinal drusenoid deposits (SDDs), and 83 were imaged longitudinally.

Results

No gaze varying structures were detected in young eyes. In aging eyes with no evidence of age-related changes, putative drusen <20 µm in diameter were visible. Gaze-dependent images revealed more drusen and many smaller drusen than visible in color fundus images. Longitudinal images showed expansion and fusion of drusen. SDDs were lower contrast, and RPE atrophy did not yield a consistent signal.

Conclusions

Gaze-dependent imaging in a commercially available FIAO fundus camera combined with image registration and postprocessing permits visualization of drusen and their progression with high contrast and resolution.

Translational Relevance

This new technique offers promise as a robust and sensitive method to detect, map, quantify, and monitor the dynamics of drusen in aging and AMD.

Clinical Manifestations of Cuticular Drusen: Current Perspectives

Cuticular drusen are part of the spectrum of age-related macular degeneration (AMD) with particular clinical and multimodal imaging characteristics. This drusen subpopulation shares several high-risk single nucleotide polymorphisms with AMD. Despite this feature, they can manifest at a relatively young age, presenting with a female preponderance. Multimodal imaging is essential for characterizing such lesions, using a combination of color fundus photographs, optical coherence tomography (OCT), fluorescein angiography (FA), and fundus autofluorescence (FAF). The classic starry-sky pattern visible on FA and the typical central hypoautofluorescent lesion with hyperautofluorescent rim on FAF is considered the result of a central retinal pigment epithelium (RPE) erosion from these triangular elevations of the RPE-basal lamina. This finding may also be responsible for the typical choroidal hypertransmission appreciated through OCT. The clinical course of cuticular drusen may be relatively benign at early stages, with small drusen presenting at a young age. However, the presence of clinical phenotypes characterized by diffuse involvement and/or accompanying large drusen in patients older than 60 years may confer a significant risk for either macular neovascularization or geographic atrophy.

Complement C5 is not critical for the formation of sub-RPE deposits in Efemp1 mutant mice

The complement system plays a role in the formation of sub-retinal pigment epithelial (RPE) deposits in early stages of age-related macular degeneration (AMD). But the specific mechanisms that connect complement activation and deposit formation in AMD patients are unknown, which limits the development of efficient therapies to reduce or stop disease progression. We have previously demonstrated that C3 blockage prevents the formation of sub-RPE deposits in a mouse model of EFEMP1-associated macular degeneration. In this study, we have used double mutant Efemp1R345W/R345W:C5-/- mice to investigate the role of C5 in the formation of sub-RPE deposits in vivo and in vitro. The data revealed that the genetic ablation of C5 does not eliminate the formation of sub-RPE deposits. Contrarily, the absence of C5 in RPE cultures promotes complement dysregulation that results in increased activation of C3, which likely contributes to deposit formation even in the absence of EFEMP1-R345W mutant protein. The results also suggest that genetic ablation of C5 alters the extracellular matrix turnover through an effect on matrix metalloproteinases in RPE cell cultures. These results confirm that C3 rather than C5 could be an effective therapeutic target to treat early AMD.

Pachydrusen, choroidal vascular hyperpermeability, and punctate hyperfluorescent spots

PURPOSE

To investigate the relationship between pachydrusen and features of choroidal vascular hyperpermeability (CVH) and punctate hyperfluorescent spots (PHS) on serial imaging in patients with polypoidal choroidal vasculopathy (PCV) or pachychoroid neovasculopathy (PNV).

METHODS

Patients diagnosed between January 2007 and June 2016 at 2 high-volume, tertiary hospitals were retrospectively reviewed with serial multimodal imaging assessment. The primary outcome was the association between drusen subtypes (hard/soft drusen, subretinal drusenoid droplets, or pachydrusen) with CVH and PHS, previously described in central serous chorioretinopathy.

RESULTS

Among the 105 eyes (105 patients; mean age, 67.0 years), 87 (82.9%) were diagnosed with PCV and 18 (17.1%) with PNV. Pachydrusen was the most frequently identified subtype (54 eyes, 51.4%). CVH (72.2% vs 41.4%, P = 0.021) and PHS (72.2% vs 44.8%, P = 0.041) were observed with greater frequency in PNV eyes. Significant correlations were found between CVH and PHS (phi coefficient φ 0.30, P = 0.003), and PHS with pachydrusen (φ 0.20, P = 0.040). Over a mean follow-up of 74.8 months, new drusen co-localizing to PHS were noted in 22 (21.0%) eyes (φ 0.54, P < 0.001).

CONCLUSION

We observed a trend of pachydrusen appearing in conjunction with PHS in PCV or PNV. Frequent localization of new drusen to these choroidal lesions was observed over long-term follow-up. PHS may be a form of late-staining "forme fruste" drusen, possibly associated with micro-ischemic changes to the choriocapillaris.

Age‐related maculopathy in the light of ischaemia

This manuscript focuses on the pathogenesis of age-related maculopathy (ARM) and the documentation of new treatments in ARM. Ischaemia will be given special consideration, as it is believed to play a central role in both early ARM and late ARM or age-related macular degeneration (AMD). Reduced choroidal and retinal blood flow causes ischaemia of Bruch's membrane, retinal pigment epithelium and neuroretina in the early course of ARM. This is thought to be the primary trigger of the condition. Chronic ischaemia upregulates vascular endothelial growth factor (VEGF), which induces abnormal vessel growth in neovascular AMD. The role of ischaemia in neovascular AMD is supported by the evidence of effective new treatments targeting VEGF.

Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is severely impaired underneath the area of geographic atrophy, and the level of impairment surrounding the lesion predicts the rate of atrophy enlargement. Macular neovascularization can be readily identified and classified using OCTA, but it is still unclear if neovascularization features with OCTA can predict the lesion’s level of activity. The choriocapillaris surrounding macular neovascularization is impaired while the more peripheral choriocapillaris is spared, implying that choriocapillaris disruption may drive neovascularization growth. With continued innovation in OCTA image acquisition and analysis methods, advancement in clinical applications and pathophysiologic discoveries in AMD are set to follow.

TOPOGRAPHIC ASSESSMENT OF CHORIOCAPILLARIS FLOW DEFICITS IN THE INTERMEDIATE AGE-RELATED MACULAR DEGENERATION EYES WITH HYPOREFLECTIVE CORES INSIDE DRUSEN

PURPOSE

To evaluate the choriocapillaris (CC) flow deficit (FD) in eyes with hyporeflective cores (HCs) inside drusen in eyes with intermediate age-related macular degeneration.

METHODS

Intermediate age-related macular degeneration subjects underwent optical coherence tomography and optical coherence tomography angiography using a Cirrus HD-optical coherence tomography (Carl Zeiss Meditec, Dublin, CA). All B-scans were inspected for the presence of drusen with an HC that was defined as dark, condense materials inside drusen. Drusen regions delineated in the manufactures advanced retinal pigment epithelium elevation map were superimposed to the compensated CC optical coherence tomography angiography images. Quantitative analysis of CC FD% was performed under drusen with and without HCs, 150-µm-wide ring region around drusen with and without HCs, drusen-free region, and whole macula.

RESULTS

Fifty eyes were included in this cross-sectional study. Twenty eyes had drusen with HCs. Thirty eyes without HCs were matched for age and sex. The CC FD% of whole macula was significantly greater in eyes with an HC than those without it (46.3% vs. 42.9%; P = 0.001). In eyes with HCs, regional CC FD% was the greater under drusen (59.8%) and in a 150-µm-wide ring surrounding drusen with HCs (53.0%) than corresponding regions for drusen without HCs (52.5% and 47.3%, respectively) (P < 0.005 in all, Bonferroni correction). The CC FD% in macular regions remote from drusen was 43.2%.

CONCLUSION

Intermediate age-related macular degeneration eyes with HCs demonstrated more impaired CC flow, compared with those without this featured. The CC was also more severely impaired directly below these drusen with HCs. These findings highlight that the appearance of HCs may be an indicator of a more advanced disease phenotype.

Changes in Retinal Structure and Ultrastructure in the Aged Mice Correlate With Differences in the Expression of Selected Retinal miRNAs

Age and gender are two important factors that may influence the function and structure of the retina and its susceptibility to retinal diseases. The aim of this study was to delineate the influence that biological sex and age exert on the retinal structural and ultrastructural changes in mice and to identify the age-related miRNA dysregulation profiles in the retina by gender. Experiments were undertaken on male and female Balb/c aged 24 months (approximately 75–85 years in humans) compared to the control (3 months). The retinas were analyzed by histology, transmission electron microscopy, and age-related miRNA expression profile analysis. Retinas of both sexes showed a steady decline in retinal thickness as follows: photoreceptor (PS) and outer layers (p < 0.01 for the aged male vs. control; p < 0.05 for the aged female vs. control); the inner retinal layers were significantly affected by the aging process in the males (p < 0.01) but not in the aged females. Electron microscopy revealed more abnormalities which involve the retinal pigment epithelium (RPE) and Bruch’s membrane, outer and inner layers, vascular changes, deposits of amorphous materials, and accumulation of lipids or lipofuscins. Age-related miRNAs, miR-27a-3p (p < 0.01), miR-27b-3p (p < 0.05), and miR-20a-5p (p < 0.05) were significantly up-regulated in aged male mice compared to the controls, whereas miR-20b-5p was significantly down-regulated in aged male (p < 0.05) and female mice (p < 0.05) compared to the respective controls. miR-27a-3p (5.00 fold; p < 0.01) and miR-27b (7.58 fold; p < 0.01) were significantly up-regulated in aged male mice vs. aged female mice, whereas miR-20b-5p (−2.10 fold; p < 0.05) was significantly down-regulated in aged male mice vs. aged female mice. Interestingly, miR-27a-3p, miR-27b-3p, miR-20a-5p, and miR-20b-5p expressions significantly correlated with the thickness of the retinal PS layer (p < 0.01), retinal outer layers (p < 0.01), and Bruch’s membrane (p < 0.01). Our results showed that biological sex can influence the structure and function of the retina upon aging, suggesting that this difference may be underlined by the dysregulation of age-related mi-RNAs.

Neovascular Age-Related Macular Degeneration: Therapeutic Management and New-Upcoming Approaches

Age-related macular degeneration (AMD) constitutes a prevalent, chronic, and progressive retinal degenerative disease of the macula that affects elderly people and cause central vision impairment. Despite therapeutic advances in the management of neovascular AMD, none of the currently used treatments cures the disease or reverses its course. Medical treatment of neovascular AMD experienced a significant advance due to the introduction of vascular endothelial growth factor inhibitors (anti-VEGF), which dramatically changed the prognosis of the disease. However, although anti-VEGF therapy has become the standard treatment for neovascular AMD, many patients do not respond adequately to this therapy or experience a slow loss of efficacy of anti-VEGF agents after repeated administration. Additionally, current treatment with intravitreal anti-VEGF agents is associated with a significant treatment burden for patients, caregivers, and physicians. New approaches have been proposed for treating neovascular AMD. Among them, designed ankyrin repeat proteins (DARPins) seem to be as effective as monthly ranibizumab, but with greater durability, which may enhance patient compliance with needed injections.

AMISH EYE STUDY: Baseline Spectral Domain Optical Coherence Tomography Characteristics of Age-Related Macular Degeneration

PURPOSE

To describe spectral domain optical coherence tomography (SD-OCT) findings in an Amish cohort to assess SD-OCT markers for early age-related macular degeneration (AMD).

METHODS

The authors performed a family-based prospective cohort study of 1,146 elderly Amish subjects (age range 50-99 years) (2,292 eyes) who had a family history of at least 1 individual with AMD. All subjects underwent complete ophthalmic examinations, SD-OCT using both Cirrus and Spectralis (20 × 20° scan area) instruments, fundus autofluorescence, infrared imaging, and color fundus photography. Spectral domain optical coherence tomography characteristics were analyzed in subjects with AMD (with and without subretinal drusenoid deposits [SDDs]) and normal healthy cohorts.

RESULTS

Participants' mean age was 65.2 years (SD ± 11). Color fundus photographic findings in 596 (53%) subjects (1,009 eyes) were consistent with AMD; the remaining 478 (43%) subjects showed no signs of AMD. The choroid was significantly thinner on OCT (242 ± 76 µm, P < 0.001) in those with AMD compared with those without (263 ± 63 µm). Subretinal drusenoid deposits were found in 143 eyes (7%); 11 of the 143 eyes (8%) had no other manifestations of AMD. Drusen volume (P < 0.001) and area of geographic atrophy (P < 0.001) were significantly greater, and choroid was significantly (P < 0.001) thinner in subjects with SDDs versus those without SDDs.

CONCLUSION

The authors describe spectral domain optical coherence tomography characteristics in an elderly Amish population with and without AMD, including the frequency of SDD. Although relatively uncommon in this population, the authors confirmed that SDDs can be found in the absence of other features of AMD and that eyes with SDDs have thinner choroids.

REvisiting Lipids in REtinal Diseases: A Focused Review on Age-related Macular Degeneration and Diabetic Retinopathy

Dyslipidemia refers to an abnormal amount of lipid in the blood, and the total cholesterol level is defined as the sum of high-density lipoprotein cholesterol, low-density lipoprotein (LDL) cholesterol, and very-LDL cholesterol concentrations. In Korea, the westernization of lifestyle habits in recent years has caused an increase in the incidence of dyslipidemia, which is an important risk factor of cardiovascular disease (CVD). Several studies have been conducted on how dyslipidemia affects not only CVD, but also chorioretinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy. Recently, a pathological model of AMD was proposed under the assumption that AMD proceeds through a mechanism similar to that of atherosclerotic CVD. However, controversy remains regarding the relationship between chorioretinal diseases and lipid levels in the blood, and the effects of lipid-lowering agents. Herein, we summarize the role of lipids in chorioretinal diseases. In addition, the effects of lipid-lowering agents on the prevention and progression of chorioretinal diseases are presented.

Matrix Metalloproteinases in Age-Related Macular Degeneration (AMD)

Age-related macular degeneration (AMD) is a complex, multifactorial and progressive retinal disease affecting millions of people worldwide. In developed countries, it is the leading cause of vision loss and legal blindness among the elderly. Although the pathogenesis of AMD is still barely understood, recent studies have reported that disorders in the regulation of the extracellular matrix (ECM) play an important role in its etiopathogenesis. The dynamic metabolism of the ECM is closely regulated by matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs). The present review focuses on the crucial processes that occur at the level of the Bruch’s membrane, with special emphasis on MMPs, TIMPs, and the polymorphisms associated with increased susceptibility to AMD development. A systematic literature search was performed, covering the years 1990–2020, using the following keywords: AMD, extracellular matrix, Bruch’s membrane, MMPs, TIMPs, and MMPs polymorphisms in AMD. In both early and advanced AMD, the pathological dynamic changes of ECM structural components are caused by the dysfunction of specific regulators and by the influence of other regulatory systems connected with both genetic and environmental factors. Better insight into the pathological role of MMP/TIMP complexes may lead to the development of new strategies for AMD treatment and prevention.

Long-term Evolution and Remodeling of Soft Drusen in Rhesus Macaques

Purpose

To characterize the evolution and structure of soft drusen in aged rhesus macaques using in vivo multimodal retinal imaging and ex vivo histologic and ultrastructural analyses as a nonhuman primate model of early age-related macular degeneration (AMD).

Methods

Multimodal imaging including fundus photography, spectral domain optical coherence tomography (SD-OCT), and fundus autofluorescence (FAF) were used to characterize and track individual drusen lesions in 20 aged rhesus macaques (mean age 23.3 ± 2.7 years) with drusenoid lesions over 2 years, followed by semithin histologic analysis and transmission electron microscopy (TEM).

Results

Although most drusen gradually increased in size, a portion spontaneously regressed or collapsed over 2 years. Histologic analyses showed that soft drusen exhibit hypertrophy and dysmorphia of overlying retinal pigment epithelium (RPE), as seen in early and intermediate AMD, but do not exhibit RPE atrophy, RPE migration, or photoreceptor degeneration characteristic of advanced AMD. Ultrastructure of soft drusen showed abundant lipid particles within Bruch's membrane and AMD-related basal linear deposits (BlinD) resembling those in human drusen.

Conclusions

The dynamic remodeling, histologic findings, and ultrastructural features of soft drusen in aged rhesus macaques support nonhuman primates as an animal model of early AMD and reveal important insights into drusen biogenesis and AMD development.

Quantifying Choriocapillaris Flow Voids in Patients With Geographic Atrophy Using Swept-Source OCT Angiography

BACKGROUND AND OBJECTIVE

To compare choriocapillaris (CC) flow voids (FVs) throughout the macula in patients with age-related macular degeneration (AMD) and geographic atrophy (GA) to age-similar controls using swept-source optical coherence tomography angiography (SS-OCTA).

PATIENTS AND METHODS

In this cross-sectional study, 12 subjects with GA secondary to nonexudative AMD and 12 age-similar controls participated. SS-OCTA was performed using a 6 mm × 6 mm scanning pattern. CC FVs were calculated using a one-standard deviation thresholding method developed from a normal database.

RESULTS

CC FVs were significantly increased in patients with GA compared with age-similar controls (P < .001). FVs within 2° of GA were significantly increased compared with the area outside 2° (P < .001). FVs beyond 2° of GA were significantly increased compared with age-similar controls (P < .001).

CONCLUSIONS

FV analysis of in vivo CC images revealed diffuse CC perfusion deficits throughout the macular region in subjects with GA secondary to nonexudative AMD. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e229-e235.].

Autoimmune-Mediated Retinopathy in CXCR5-Deficient Mice as the Result of Age-Related Macular Degeneration Associated Proteins Accumulation

Previous research has shown that CXCR5^−/− mice develop retinal degeneration (RD) with age, a characteristic related to age macular degeneration (AMD). RD in these mice is not well-understood, and in this study, we sought to characterize further the RD phenotype and to gain mechanistic insights into the function of CXCR5 in the retina. CXCR5^−/− and WT control mice were used. Fundus images demonstrated a significant (p < 0.001) increase of hypo-pigmented spots in the retina of aged CXCR5^−/− mice compared with WT control mice. PAS staining indicated localization of deposits in the sub-retinal pigment epithelia (RPE) layer. AMD-associated proteins Cryab, amyloid beta, and C3d were detected within the RPE/sub-RPE tissues by immunofluorescence (IF). In addition, western blot analysis of COX-2, Arg1, and VEGF-a revealed an increase in the signaling of these molecules within the RPE/choroid complex. Transmission electron microscopy (TEM) indicated a drusen-like structure of sub-RPE deposits with an accumulation of vacuolated cellular debris. Loss of photoreceptors was detected by peanut lectin staining and was corroborated by a reduction in MAP2 signaling. Loss of blood-retinal barrier integrity was demonstrated by a reduction of ZO-1 expression. Inflammatory cells were detected in the sub-RPE space, with an increase in IBA-1 positive microglia cells on the surface of the RPE. Mass spectrometry analysis of CXCR5^−/− mouse RPE/choroid proteins extracts, separated by SDS-page and incubated with autologous serum, identified autoantibodies against AMD-associated proteins: Cryaa, Cryab, and Anxa2. In vitro evaluations in BV-2 cell culture indicated a significant increase in production of Arg-1 (p < 0.001) and COX-2 (p < 0.01) in the presence of anti-CXCR5 antibody when compared with Igg-treated control BV-2 cells stimulated with IL-4 and TNFα/IFNγ, respectively. Anti-CXCR5 antibody treatment without stimulating agents did not affect Arg-1 and COX-2 expression; this suggests that CXCR5 may have a regulatory role in microglia cells activation. These results indicate that with age, CXCR5^−/− mice develop RD characterized by microglia dysfunction, increased production of CXCL13 in the RPE progressive photoreceptor, neuronal loss, and sub-RPE deposition of cellular debris, resulting in the production of immunogenic proteins and autoimmune-mediated RD.

The Placental Growth Factor Pathway and Its Potential Role in Macular Degenerative Disease

There is growing evidence that placental growth factor (PlGF) is an important player in multiple pathologies, including tumorigenesis, inflammatory disorders and degenerative retinopathies. PlGF is a member of the vascular endothelial growth factor (VEGF) family and in the retina, binding of this growth factor to specific receptors is associated with pathological angiogenesis, vascular leakage, neurodegeneration and inflammation. Although they share some receptor signalling pathways, many of the actions of PlGF are distinct from VEGF and this has revealed the enticing prospect that it could be a useful therapeutic target for treating early and late stages of diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Recent research suggests that modulation of PlGF could also be important in the geographic atrophy (GA) form of late AMD by protecting the outer retina and the retinal pigment epithelium (RPE). This review discusses PlGF and its signalling pathways and highlights the potential of blocking the bioactivity of this growth factor to treat irreversible visual loss due to the two main forms of AMD.

The association of matrix metalloproteinases polymorphisms and interleukins in advanced age-related macular degeneration

PURPOSE

To assess the impact of matrix metalloproteinase (MMP)1-1607 1G/2G (rs1799750), MMP7-181 A/G (rs11568818) single-nucleotide polymorphism and systemic cytokins interleukin-1 beta (IL-1β), IL-6 levels on the development of exudative age-related macular degeneration (eAMD) Methodology: The study group comprised 282 patients with eAMD, and the control group enrolled 379 randomly selected persons. The genotyping of MMP1-1607 (rs1799750) and MMP7-181 (rs11568818) was performed by using the polymerase chain reaction-based restriction fragment length polymorphism method. To determine IL-1β and IL-6 serum levels, the immunoenzymatic method with monoclonal antibodies coated plates was performed.

RESULTS

MMP1 rs1799750 1G/2G genotype was more frequently found in the development of eAMD. It was associated with a 4.3-fold increased risk for eAMD under the codominant model and a 4.9-fold increased risk for eAMD under the overdominant model. The effect was more pronounced at the age of less than 65 years. IL-1β concentration was significantly higher for MMP1 rs1799750 1G/1G genotype and MMP7 rs11568818 A/G genotype in eAMD patients compared with control group subjects.

CONCLUSIONS

MMP1 rs1799750 1G/2G genotype was found to play a significant role in the development of eAMD at the age of less than 65 years. IL-1β concentration was significantly higher in eAMD patients for MMP1 rs1799750 1G/1G genotype and MMP7 rs11568818 A/G genotype compared with control group subjects.

Choriocapillaris flow impairment surrounding geographic atrophy correlates with disease progression

Purpose

To evaluate the correlation between the choriocapillaris (CC) flow alterations around geographic atrophy (GA) and the GA yearly growth rate (yGR) in patients with dry age-related macular degeneration (AMD).

Methods

We retrospectively reviewed and analyzed spectral domain optical coherence tomography (SD-OCT) and SD-OCT angiography images of consecutive patients with GA acquired using the Cirrus OCT at the Doheny Eye Centers between 2015 and 2017. All eligible patients had one 6 x 6 mm OCTA scan acquired during the first visit (considered as baseline) and two fovea-centered 512 x 128 macular cubes (6 x 6 mm) acquired at baseline and after a minimum of 12 months.

Main outcome measures

The fundus images from the OCT volumes were used to manually delineate the GA area and calculate the yGR after square root transformation. The en-face angiogram at the level of the CC was analyzed for the percentage of flow voids (FV) outside the atrophic lesion (FV_OUT) and in the para- and peri-atrophy regions (FV₅₀₀ and FV₁₀₀₀ respectively; two concentric 500 μm wide rings around the atrophy edge). These values, together with the difference between FV₅₀₀ and FV₁₀₀₀ (ΔFV), were then correlated with the corresponding yGR.

Results

Thirty-three eyes of 23 patients were eligible for the analysis. The mean yGR was 0.23 ± 0.17 mm/years.

At baseline, the mean FV_OUT was 41.86 ± 2.71%, while FV₅₀₀ and FV₁₀₀₀ were 46.4 ± 4.17% and 42.51 ± 2.65% respectively. The mean ΔFV was 3.89 ± 2.6%. While in the univariable analysis, the yGR was significantly associated with FV₅₀₀ and with ΔFV (both p < 0.001), in multivariable model the association remained significant only with ΔFV (p < 0.001).

Conclusions

Our study reports a correlation between the CC flow impairment around the atrophic lesions and their yGR in patients with GA. If replicated in future longitudinal studies, the choriocapillaris FV in the para-and peri-atrophy regions may prove to be useful parameters for evaluating the prognosis of these eyes.