Racial differences in the prevalence of age-related macular degeneration: the Baltimore Eye Survey

Translational Research and Therapies for Neuroprotection and Regeneration of the Optic Nerve and Retina: A Narrative Review

Most retinal and optic nerve diseases pose significant threats to vision, primarily due to irreversible retinal neuronal cell death, a permanent change, which is a critical factor in their pathogenesis. Conditions such as glaucoma, retinitis pigmentosa, diabetic retinopathy, and age-related macular degeneration are the top four leading causes of blindness among the elderly in Japan. While standard treatments-including reduction in intraocular pressure, anti-vascular endothelial growth factor therapies, and retinal photocoagulation-can partially delay disease progression, their therapeutic effects remain limited. To address these shortcomings, a range of neuroprotective and regenerative therapies, aimed at preventing retinal neuronal cell loss, have been extensively studied and increasingly integrated into clinical practice over the last two decades. Several of these neuroprotective therapies have achieved on-label usage worldwide. This narrative review introduces several neuroprotective and regenerative therapies for retinal and optic nerve diseases that have been successfully translated into clinical practice, providing foundational knowledge and success stories that serve as valuable references for researchers in the field.

Advanced nanomedicines for the treatment of age-related macular degeneration

The critical and unmet medical need for novel therapeutic advancements in the treatment of age-related macular degeneration (AMD) cannot be overstated, particularly given the aging global population and the increasing prevalence of this condition. Current AMD therapy involves intravitreal treatments that require monthly or bimonthly injections to maintain optimal efficacy. This underscores the necessity for improved approaches, prompting recent research into developing advanced drug delivery systems to prolong the intervals between treatments. Nanoparticle-based therapeutic approaches have enabled the controlled release of drugs, targeted delivery of therapeutic materials, and development of smart solutions for the harsh microenvironment of diseased tissues, offering a new perspective on ocular disease treatment. This review emphasizes the latest pre-clinical treatment options in ocular drug delivery to the retina and explores the advantages of nanoparticle-based therapeutic approaches, with a focus on AMD, the leading cause of irreversible blindness in the elderly.

RPE melanin and its influence on the progression of AMD

OBJECTIVE

The aim of this review article is to summarize the latest findings and current understanding of the origin of melanin in the retinal pigment epithelium (RPE), its function within the RPE, its role in the pathogenesis of age-related macular degeneration (AMD), its effect on retinal development, and its potential therapeutic benefit in the treatment of AMD.

METHODS

A comprehensive search of peer-reviewed journals was conducted using various combinations of key terms such as "melanin," "retinal pigment epithelium" or "RPE," "age-related macular degeneration" or AMD," "lipofuscin," "oxidative stress," and "albinism." Databases searched include PubMed, Scopus, Science Direct, and Google Scholar. 147 papers published between the years of 1957 and 2023 were considered with an emphasis on recent findings.

SUMMARY OF FINDINGS

AMD is thought to result from chronic oxidative stress within the RPE that results in cellular dysfunction, metabolic dysregulation, inflammation, and lipofuscin accumulation. Melanin functions as a photoscreener, free radical scavenger, and metal cation binding reservoir within the RPE. RPE melanin does not regenerate, and it undergoes degradation over time in response to chronic light exposure and oxidative stress. RPE melanin is important for retinal development and RPE function, and in the aging eye, melanin loss is associated with increased lipid peroxidation, inflammation, and the accumulation of toxic oxidized cellular products. Therefore, melanin-based treatments may serve to preserve RPE and retinal function in AMD.

CONCLUSIONS

The pathogenesis of AMD is not fully understood, but RPE dysfunction and melanin loss in response to chronic oxidative stress and inflammation are thought to be primary drivers of the disease. Due to melanin's antioxidative effects, melanin-based nanotechnology represents a promising avenue for the treatment of AMD.

Retinal characteristics in eyes with pathologic myopia among individuals self-identifying as Black

OBJECTIVE

Investigate retinal characteristics of pathologic myopia (PM) among patients self-identifying as Black.

DESIGN

Retrospective cohort single-institution retrospective medical record review.

METHODS

Adult patients between January 2005 and December 2014 with International Classification of Diseases (ICD) codes consistent with PM and given 5-year follow-up were evaluated. The Study Group consisted of patients self-identifying as Black, and the Comparison Group consisted of those not self-identifying as Black. Ocular features at study baseline and 5-year follow-up visit were evaluated.

RESULTS

Among 428 patients with PM, 60 (14%) self-identified as Black and 18 (30%) had baseline and 5-year follow-up visits. Of the remaining 368 patients, 63 were in the Comparison Group. For the study (n = 18) and Comparison Group (n = 29), median (25th percentile, 75th percentile) baseline visual acuity was 20/40 (20/25, 20/50) and 20/32 (20/25, 20/50) in the better-seeing eye and 20/70 (20/50, 20/1400) and 20/100 (20/50, 20/200), respectively, in the worse-seeing eye. In the eyes that did not have choroidal neovascularization (CNV) in the study and Comparison Group, median study baseline optical coherence tomography central subfield thickness was 196 μm (169, 306 μm) and 225 μm (191, 280 μm), respectively, in the better-seeing eye and 208 μm (181, 260 μm) and 194 μm (171, 248 μm), respectively, in the worse-seeing eye. Baseline prevalence of CNV was 1 Study Group eye (3%) and 20 Comparison Group eyes (34%). By the 5-year visit, zero (0%) and 4 (15%) additional eyes had CNV in the study and Comparison Group, respectively.

CONCLUSION

These findings suggest that the prevalence and incidence of CNV may be lower in patients with PM self-identifying as Black when compared with individuals of other races.

ASSOCIATION OF ORAL MONTELUKAST WITH REDUCED ODDS OF DEVELOPING EXUDATIVE AGE-RELATED MACULAR DEGENERATION

PURPOSE

This study was conducted to evaluate the association of oral montelukast, selective antagonism for cysteinyl leukotriene receptor 1, with reduced odds of exudative age-related macular degeneration (exAMD) development.

METHODS

This case-control study was conducted using institutional cohort finder tool, and included 1913 patients with exAMD (ICD: H35.32 and 362.52) and 1913 age- and gender-matched control subjects without exAMD. Subanalysis among 1913 exAMD and 324 nonexudative AMD was also conducted.

RESULTS

A total of 47 (2.5%) exAMD cases were identified to have a history of oral montelukast use before exAMD diagnosis, compared with 84 (4.4%) controls. Montelukast usage was significantly associated with reduced odds of exAMD in the multivariable analysis (adjusted odds ratio [OR]: 0.50, 95% confidence interval: 0.31-0.80) and nonsteroidal anti-inflammatory drug usage (adjusted OR: 0.69). Caucasian race, history of smoking, and nonexudative macular degeneration in either eye were also found to have a significant relationship with increased odds of exAMD. In the subanalysis, montelukast usage showed significant association with reduced odds of developing exAMD from nonexudative AMD (adjusted OR: 0.53, 95% confidence interval: 0.29-0.97) and the presence of atopic disease (adjusted OR: 0.60).

CONCLUSION

The study results suggested that oral montelukast is linked to reduced odds of exAMD development.

The Impact of Diabetic Retinopathy on the Choriocapillaris in Neovascular AMD

Purpose

To investigate the impact of diabetic retinopathy (DR) on morphological choriocapillaris (CC) modifications in eyes with type 1 macular neovascularization (MNV) secondary to AMD using optical coherence tomography angiography (OCTA).

Methods

Eyes with AMD-related type 1 MNV with and without DR were prospectively included. We performed 3 × 3 mm OCTA scans at two visits: before the loading phase of intravitreal injections of aflibercept (T1) and 1 month after the last injection (T2). OCTA En face flow images of the CC were analyzed for flow deficit percentage (FD%), FD average area and FD number in a 500-µm-wide ring surrounding the dark halo (DH) around type 1 MNV.

Results

A total of 65 eyes, out of which 30 eyes had mild DR, were included. In the group without diabetes, there was a gradual reduction in FD% in the CC ring around the DH after antiangiogenic therapy, indicating reperfusion of the CC (P = 0.003). However, in the DR group, there were no significant changes in CC parameters between the two study visits. Specifically, the FD% in the CC ring around the DH did not show a significant reduction at T2 compared with T1 values (P > 0.05). Furthermore, the comparison of the variation in FD% between the two groups was statistically significant. The nondiabetic group exhibited a gradual CC reperfusion after the loading phase of aflibercept, whereas the diabetic eyes did not show significant changes (P = 0.029).

Conclusions

The CC surrounding the DH associated to type 1 MNV exhibited greater hypoperfusion in diabetic eyes compared with eyes without diabetes, both before starting therapy and after the loading phase. Hence, DR may be a potential risk factor in the development and progression of late-stage AMD and may also influence the response to antiangiogenic therapy.

Diverse Research Teams and Underrepresented Groups in Clinical Studies

Importance

Several ophthalmic diseases disproportionately affect racial and ethnic minority patients, yet most clinical trials struggle to enroll cohorts that are demographically representative of disease burden; some barriers to recruitment include time and transportation, language and cultural differences, and fear and mistrust of research due to historical abuses. Incorporating diversity within the research team has been proposed as a method to increase trust and improve engagement among potential study participants.

Objective

To examine how demographic factors of potential research participants and personnel may be associated with patient consent rates to participate in prospective ophthalmic clinical studies.

Design, Setting, and Participants

This retrospective cohort study included patients from an urban, academic hospital who were approached for consent to participate in prospective ophthalmic clinical studies conducted between January 2015 and December 2021.

Main Outcomes and Measures

Multivariable logistic regression assessing associations between patient and research personnel demographics and rates of affirmative consent to participate was used.

Results

In total, 1380 patients (mean [SD] age, 58.6 [14.9] years; 50.3% male) who were approached for consent to participate in 10 prospective ophthalmic clinical studies were included. Of prospective patients, 566 (43.5%) were Black; 327 (25.1%), Hispanic or Latino; 373 (28.6%), White; 36 (2.8%), other race and ethnicity; and 78 (5.8%) declined to answer. Black patients (odds ratio [OR], 0.32; 95% CI, 0.24-0.44; P < .001) and Hispanic or Latino patients (OR, 0.31; 95% CI, 0.20-0.47; P < .001) were less likely to consent compared with White patients. Patients with lower socioeconomic status were less likely to consent than patients with higher socioeconomic status (OR, 0.43; 95% CI, 0.33-0.53; P < .001). Concordance between patient and research staff race and ethnicity was associated with increased odds of affirmative consent (OR, 2.72; 95% CI, 1.99-3.73; P < .001).

Conclusions and Relevance

In this cohort study, patients from underrepresented racial and ethnic groups and those with lower socioeconomic status were less likely to participate in ophthalmic clinical studies. Concordance of race and ethnicity between patients and research staff was associated with improved participant enrollment. These findings underscore the importance of increasing diversity in clinical research teams to improve racial and ethnic representation in clinical studies.

Neovascular Age-Related Macular Degeneration in a Predominantly Black Population

BACKGROUND AND OBJECTIVE

We intend to study the characteristics and outcomes of an understudied patient population with neovascular age-related macular degeneration (nAMD).

PATIENTS AND METHODS

This retrospective study evaluated presenting features and outcomes in a predominantly Black patient population with nAMD. A multivariate regression explored baseline characteristics predictive of 1-year vision.

RESULTS

Sixty-three eyes were included. The median (interquartile range) baseline vision was 20/300 (20/80 to counting fingers). Patients' baseline optical coherence tomography findings showed a mean central subfield thickness of 336 µm; 80% (n = 35) and 41% (n = 18) had fluid and central scarring, respectively. The primary predictor for vision at year-one was baseline vision (P = 0.03, 95% CI: 0.04 to 0.91). All of those who gained ≥ 3 lines of vision lacked central scarring at baseline.

CONCLUSION

Further studies are needed to investigate how to improve earlier detection and treatment of nAMD in this patient population. [Ophthalmic Surg Lasers Imaging Retina 2023;54:580-584.].

Fine particulate matter measured by satellites predicts the risk of age-related macular degeneration in a longitudinal cohort study

Although studies have revealed that ambient particulate matter (PM) has detrimental effects on the ocular surface, there have been limited reports detailing the effect of ambient PM on the posterior segment of the eye. A large-scale longitudinal cohort study evaluating the association between fine PM, especially PM2.5, and the retina could elucidate the risk of ambient pollutants for retinal diseases. We investigated the association between PM2.5 and the development of age-related macular degeneration (AMD). We conducted a population-based cohort study of 4,284,128 participants in Taiwan between 2001 and 2011. PM2.5 was continuously measured by satellites and subsequently assigned to each geographic district along with its postcode. A time-dependent Cox proportional-hazard model was used to assess the overall effects of average PM2.5. We used distributed lag non-linear models to evaluate the dose-response relationship between PM2.5 and AMD development. The annual mean of PM2.5 exposure was 34.23 ± 7.17 μg/m3. The PM2.5 concentrations were highest in spring, followed by those in winter, autumn, and summer. Twelve thousand ninety-five new AMD cases were reported during the study period. After adjusting for covariates, the AMD risk increased by 19% (95% confidence interval 1.13-1.25) for a 10 μg/m3 PM2.5 increase. The present study demonstrated that chronic exposure to PM2.5 increases the risk of AMD. Almost half of the Taiwanese live in a polluted area where the PM2.5 levels are higher than the World Health Organization recommended air quality guideline of 10 μg/m3 had a 1.4-fold risk, which significantly increases concern about their visual health and social burden.

The Ethical and Societal Considerations for the Rise of Artificial Intelligence and Big Data in Ophthalmology

Medical specialties with access to a large amount of imaging data, such as ophthalmology, have been at the forefront of the artificial intelligence (AI) revolution in medicine, driven by deep learning (DL) and big data. With the rise of AI and big data, there has also been increasing concern on the issues of bias and privacy, which can be partially addressed by low-shot learning, generative DL, federated learning and a "model-to-data" approach, as demonstrated by various groups of investigators in ophthalmology. However, to adequately tackle the ethical and societal challenges associated with the rise of AI in ophthalmology, a more comprehensive approach is preferable. Specifically, AI should be viewed as sociotechnical, meaning this technology shapes, and is shaped by social phenomena.

Human-induced pluripotent stem cells-derived retinal pigmented epithelium, a new horizon for cells-based therapies for age-related macular degeneration

Retinal pigment epithelium (RPE) degeneration is the hallmark of age-related macular degeneration (AMD). AMD, as one of the most common causes of irreversible visual impairment worldwide, remains in need of an appropriate approach to restore retinal function. Wet AMD, which is characterized by neovascular formation, can be stabilized by currently available therapies, including laser photocoagulation, photodynamic therapy, and intraocular injections of anti-VEFG (anti-vascular endothelial growth factor) therapy or a combination of these modalities. Unlike wet AMD, there is no effective therapy for progressive dry (non-neovascular) AMD. However, stem cell-based therapies, a part of regenerative medicine, have shown promising results for retinal degenerative diseases such as AMD. The goal of RPE cell therapy is to return the normal structure and function of the retina by re-establishing its interaction with photoreceptors, which is essential to vision. Considering the limited source of naturally occurring RPE cells, recent progress in stem cell research has allowed the generation of RPE cells from human pluripotent cells, both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSC). Since iPSCs face neither ethical arguments nor significant immunological considerations when compared to ESCs, they open a new horizon for cell therapy of AMD. The current study aims to discuss AMD, review the protocols for making human iPSCs-derived RPEs, and summarize recent developments in the field of iPSC-derived RPEs cell therapy.

Association of Age-Related Macular Degeneration with Prior Hyperthyroidism and Hypothyroidism: A Case-Control Study

Prior studies suggest a possible association between thyroid disease and the subsequent development of age-related macular degeneration (AMD), although it remains inconclusive. This study aimed to evaluate the association of AMD with prior hyper-/hypothyroidism based on nationwide population-based data. We retrieved records of the study patients from the National Health Insurance Research Database, 7522 patients with a first-time diagnosis of AMD and 7522 propensity score-matched controls. Multiple logistic regression analyses were performed to explore the association of neovascular AMD with previously diagnosed hyperthyroidism or hypothyroidism. The Chi-square test shows that there was a statistically significant difference in the prevalence of prior hyperthyroidism between cases and controls (1.18 vs. 0.13%, p < 0.001). Furthermore, there was a statistically significant difference the prevalence of prior hypothyroidism between cases and controls (0.44 vs. 0.69%, p < 0.001). Multiple logistic regression analysis reveals that AMD was statistically and significantly associated with prior hyperthyroidism after adjusting for age, sex, monthly income, geographical location, urbanization level, hypertension, hyperlipidemia, diabetes, and coronary heart disease (odds ratio (OR) = 9.074, 95% CI = 4.713−17.471). The adjusted OR of prior hypothyroidism in patients with AMD was 3.794 (95% CI: 2.099~6.858) when compared to the controls. We conclude that patients with thyroid dysfunction are at higher risk of developing AMD Results suggest that these patients could benefit from proactive regular eye checkups to detect evolving eye pathology, even while vision remains normal during the initial phases.

[Epidemiological and clinical profile of age-related macular degeneration in Cameroon]

PURPOSE

To determine the epidemiological and clinical characteristics of age-related macular degeneration in patients in Yaoundé.

METHODOLOGY

A multicenter, analytical and cross-sectional study was carried out from March 2017 to June 2018 in four hospitals in the city of Yaoundé. Included were all consenting patients aged at least 40 years with an established diagnosis of AMD both clinically and by imaging. The data were analyzed with CSPro software version 7.0. Chi² and Student's "t" tests in univariate mode and logistic regression in multivariate mode were used with a significance of P≤5%.

RESULTS

Of the 9,989 patients who were seen during the 16-month study period, 38 met our inclusion criteria - a frequency of 0.4%. The sex ratio was 0.3, and the mean age was 68±11 years. As a function of geographic origin, AMD is more common in patients from the forest and mountain areas. The systemic comorbidities associated recorded were hypertension (47.4%) and diabetes (21.1%). After optical correction, 60 of 76 eyes (78.9%) had useful visual acuity according to WHO criteria, and the rate of blindness was 9.2%. Fundus examination revealed fewer lesions than optical coherence tomography, which demonstrated miliary drusen in 57 (75%) eyes, serous drusen in 27 (35.5%), retinal atrophy in 19 (25%) and neovascularization in 3 (3.9%). The clinical forms were dominated by age-related maculopathy, found in 45 eyes (69.2%), followed by atrophic AMD in 17 (26.2%) and finally by exudative AMD in 3 (4.6%), for a total of 65 out of 76 eyes. Age was related to the risk of MLA and atrophic AMD (P≤0.05).

CONCLUSION

AMD is an uncommon pathology in our setting, predominant in women over the age of 60 years.

Macular thickness varies with age-related macular degeneration genetic risk variants in the UK Biobank cohort

To evaluate the influence AMD risk genomic variants have on macular thickness in the normal population. UK Biobank participants with no significant ocular history were included using the UK Biobank Resource (project 2112). Spectral-domain optical coherence tomography (SD-OCT) images were taken and segmented to define retinal layers. The influence of AMD risk single-nucleotide polymorphisms (SNP) on retinal layer thickness was analysed. AMD risk associated SNPs were strongly associated with outer-retinal layer thickness. The inner-segment outer segment (ISOS)-retinal pigment epithelium (RPE) thickness measurement, representing photoreceptor outer segments was most significantly associated with the cumulative polygenic risk score, composed of 33 AMD-associated variants, resulting in a decreased thickness (p = 1.37 × 10-67). Gene-gene interactions involving the NPLOC4-TSPAN10 SNP rs6565597 were associated with significant changes in outer retinal thickness. Thickness of outer retinal layers is highly associated with the presence of risk AMD SNPs. Specifically, the ISOS-RPE measurement. Changes to ISOS-RPE thickness are seen in clinically normal individuals with AMD risk SNPs suggesting structural changes occur at the macula prior to the onset of disease symptoms or overt clinical signs.

Global Incidence, Progression, and Risk Factors of Age-Related Macular Degeneration and Projection of Disease Statistics in 30 Years: A Modeling Study

OBJECTIVE

Age-related macular degeneration(AMD) has become a major cause of visual impairment worldwide, especially in the elderly. Estimates of incidence, progression rates, and risk factors of AMD vary among studies, complicating the understanding of its epidemiology.

METHODS

For this systematic review and meta-analysis, literature published up to March 1, 2021, was searched in both English and Chinese databases. Hierarchical Bayesian approaches were used to estimate pooled incidence, progression, and 95% credible intervals (CrIs).

RESULTS

Thirty studies were included. The pooled annual early and late AMD incidence rates were 1.59 (95% CrI: 1.18-2.11) and 0.23 (95% CrI: 0.14-0.34) per 100 person-years, respectively. The annual progression rate of AMD was 5.5 (95% CrI: 2.3-8.8) per 100 person-years. Smoking was an independent risk factor for both early and late AMD, whereas age, high-density lipoprotein cholesterol, and alcohol consumption were risk factors for early AMD incidence only. The projected number of new cases of early and late AMD in 2050 would be 39.05 million (95% CrI: 23.12-63.57) and 6.41 million (95% CrI: 3.37-13.22), respectively.

CONCLUSION

The prediction the number of new cases of AMD is not equal across the globe. Our findings indicate the need for more rigorous control and prevention measures in AMD focus on its risk factors for early intervention. The epidemiological estimates reported in this study could inform to identify effective strategies for preventing AMD worldwide.

Distinct Nuclear Architecture of Photoreceptors and Light-Induced Behaviors in Different Strains of Mice

Purpose

The mouse retina is considered a remarkable model for studying gene functions. However, variations in genetic background influence phenotypes in the mammalian retina. Therefore this study aimed to investigate the effects of the genetic background on the nuclear architecture of photoreceptor cells and the light-induced behavior in C57BL/6, 129 × 1/svj, and ICR mice.

Methods

The nuclear architecture of photoreceptor cells was investigated using various staining methods on postnatal day 21 (P21). Murine behavior was observed using a light-dark compartment test.

Results

The outer nuclear layer and retina were significantly thicker in C57BL/6 mice than in 129 × 1/svj mice. The percentage of photoreceptors with one chromocenter was significantly higher in C57BL/6 mice than in 129 × 1/svj and ICR mice on P21. The numbers of photoreceptor cells in C57BL/6 and ICR mice were significantly higher than those in 129 × 1/svj mice. The behavior test revealed that the walking distance and velocity in the light compartment were increased in C57BL/6 and ICR mice compared to 129 × 1/svj mice.

Conclusions

Different mouse strains had a distinct nuclear architecture of photoreceptors on P21, and C57BL/6 and ICR mice were more active than 129 × 1/svj mice in response to light-induced stress.

Translational Relevance

This study demonstrates a technique for assessing retinal structures and nuclear architecture in various strains of mice, which are often used to model human retinal disease. Hence, this study may help to elucidate the effect of genetic or disease-induced variance in retinal architecture and the organization of photoreceptor nuclear content on visual function in humans.

Racial/Ethnic Disparities in Ophthalmology Clinical Trials Resulting in US Food and Drug Administration Drug Approvals From 2000 to 2020

Importance

Diverse, representative enrollment in pivotal clinical trials is vital to sufficiently power subgroup analyses and ensure equity and validity of trial results.

Objective

To evaluate the racial/ethnic representation, trends, and disparities in clinical trials leading to US Food and Drug Administration (FDA) ophthalmology drug approvals from 2000 to 2020.

Design, Setting, and Participants

This cohort study used data from participants in clinical trials of drugs for neovascular age-related macular degeneration (AMD), open-angle glaucoma (OAG), and expanded indications for diabetic retinopathy (DR) from January 1, 2000, to December 31, 2020. Trial data were sourced from FDA reviews, ClinicalTrials.gov, and relevant linked studies. National expected racial/ethnic proportions were sourced from public National Eye Institute prevalence data as well as published rates scaled using US Census Bureau data.

Main Outcomes and Measures

The primary outcome measures were the distribution of and change over time in the racial/ethnic proportion of participants in clinical trials leading to FDA approval of drugs for AMD, OAG, and DR.

Results

During the 20-year period, 31 clinical trials were identified for 13 medications with 18 410 participants. The distribution of trial participants was different from the expected trial distribution for most approvals with regard to race/ethnicity (12 drugs) and sex (10 drugs). Compared with the first decade (2000-2010), trials conducted in the second decade (2011-2020) showed increases in enrollment of Asian (odds ratio [OR], 2.30; 95% CI, 1.97-2.68; P < .001) and Hispanic or Latinx participants (OR, 1.74; 95% CI, 1.49-2.03; P < .001) for AMD, Asian participants (OR, 2.21; 95% CI, 1.46-3.42; P < .001) for DR, and Black (OR, 1.60; 95% CI, 1.43-1.78; P < .001) and Hispanic or Latinx participants (OR, 10.31; 95% CI, 8.05-13.35; P < .001) for OAG. There was a decrease in Black participants in DR trials (OR, 0.58; 95% CI, 0.42-0.79; P < .001). Based on these trends, the enrollment incidence ratio is expected to worsen by 2050, with overrepresentation of white participants vs underrepresentation of Black and Hispanic or Latinx participants in trials of drugs for AMD (1.08 vs 0.04 vs 0.77), DR (1.83 vs 0.87 vs 0.59), and OAG (1.62 vs 0.90 vs 0.37).

Conclusions and Relevance

In this cohort study, Black, Hispanic or Latinx, and other non-White participants were underrepresented in clinical trials leading to FDA ophthalmology drug approvals compared with the expected disease burden and racial/ethnic distribution in the US. Although there was meaningful improvement from 2000 to 2020, further efforts to increase minority enrollment in clinical trials seem to be warranted.

Analysis of association of risk factors for age-related macular degeneration

PURPOSE

To evaluate the significance of risk factors and analyze their interrelationship in developing age-related macular degeneration (AMD).

MATERIALS AND DESIGN

This is a multicenter, cross-sectional study conducted in eight ophthalmology centers in Europe. The STARS (Simplified Thea AMD Risk-Assessment Scale) questionnaire was used to assess 12 risk factors grouped in four major categories. We used Welch's t-test/F ratios to determine statistically significant changes. The principal component analysis was done to investigate the association between risk factors.

RESULTS

There were 3297 participants included in our data analysis. Nineteen percent of patients had a high risk of developing AMD, whilst 45.92% and 34.85% had moderate and small risk, respectively. Atherosclerosis appeared as the most relevant risk indicator for AMD development (Cohen's d = 0.861). Tukey's post hoc analysis of the smoking variable showed that ex-smokers (p < 0.001) have a significantly high risk of developing AMD. The Welch's t-test showed pseudophakic patients have a higher risk of developing AMD than phakic ones. Then, we conducted the principal component analysis, which revealed a significant connection between smoking and male gender and between smoking and atherosclerosis. Pseudophakic patients were generally older and had more often myocardial infarction as compared to phakic patients. We showed that higher BMI, history of arterial hypertension, hypercholesterolemia, and atherosclerosis tend to occur together as risk factors for AMD.

CONCLUSION

Risk factors evaluated in our study should be considered for the development of AMD.

Association of metformin and development of dry age-related macular degeneration in a U.S. insurance claims database

PURPOSE

To assess whether metformin is associated with dry age-related macular degeneration (dAMD) development.

METHODS

In this retrospective cohort study, patients enrolled in a nationwide U.S. medical insurance claims database from 2002 to 2016 were included if they had diabetes mellitus, were ⩾55 years old, and were enrolled for ⩾2 years without a prior AMD diagnosis. The primary exposure was metformin use analyzed as either active or prior use or cumulative metformin dosage over the study period. A time updating Cox proportional hazard regression was used to estimate the hazard ratio of dAMD incidence with metformin exposure.

RESULTS

Among 1,007,226 diabetic enrollees, 53.3% were female and 66.4% were white with a mean hemoglobin A1c of 6.8%. Of eligible enrollees, 166,115 (16.5%) were taking metformin at the index date. Over the study period, 29,818 (3.0%) participants developed dAMD. In the active versus prior use of metformin model, active use conferred an increased hazard of developing dAMD (HR, 1.08; 95% CI, 1.04-1.12) while prior use had a decreased hazard (HR, 0.95; 95% CI 0.92-0.98). The cumulative metformin dosage model showed a significant trend toward increased hazard of dAMD incidence with increasing cumulative dosage (p < 0.001), with the lowest dosage quartile having decreased hazard of dAMD incidence (HR, 0.95; 95% CI, 0.91-0.99) and the highest having increased hazard (HR, 1.07; 95% CI, 1.01-1.13).

CONCLUSIONS

Small, conflicting associations between metformin exposure and development of dAMD were observed depending on cumulative dosage and whether drug use was active, suggesting metformin did not substantially affect the development of dAMD.

Neovascular Macular Degeneration: A Review of Etiology, Risk Factors, and Recent Advances in Research and Therapy

Neovascular age-related macular degeneration (exudative or wet AMD) is a prevalent, progressive retinal degenerative macular disease that is characterized by neovascularization of the choroid, mainly affecting the elderly population causing gradual vision impairment. Risk factors such as age, race, genetics, iris color, smoking, drinking, BMI, and diet all play a part in nvAMD's progression, with anti-vascular endothelial growth factor (anti-VEGF) therapy being the mainstay of treatment. Current therapeutic advancements slow the progression of the disease but do not cure or reverse its course. Newer therapies such as gene therapies, Rho-kinase inhibitors, and levodopa offer potential new targets for treatment.

Association of Ocular Antihypertensive Medications and the Development and Progression of Age-related Macular Degeneration in a U.S. Insurance Claims Database

Purpose/Aim: To assess whether ocular antihypertensives are associated with the development and progression of age-related macular degeneration (AMD).Materials and Methods: This retrospective, observational cohort study using healthcare claims data from a U.S. nationwide managed-care network between January 1, 2006 and December 31, 2016, included enrollees ≥40 years old with primary open-angle glaucoma with or without a diagnosis of nonexudative AMD at the index date. Hazard ratios (HR) for developing AMD or progressing from nonexudative to exudative AMD with exposure to ocular antihypertensive medications were analyzed.Results: Of 132 963 eligible enrollees, 118 174 (87.5%) had no diagnosis of AMD at baseline while 14 789 (12.5%) had adiagnosis of nonexudative AMD. Prostaglandin analog exposure had adecreased hazard of developing AMD among individuals without baseline disease (HR, 0.90; 95% CI, 0.87-0.94; p< .0001), while topical alpha₂-agonist exposure demonstrated an increased hazard of AMD development (HR, 1.08; 95% CI, 1.03-1.14; p= .004). Among patients with baseline nonexudative AMD, topical carbonic anhydrase inhibitor exposure was associated with adecreased hazard of progressing to exudative disease (HR, 0.84; 95% CI, 0.71-0.99; p= .04) while topical alpha₂-agonists had increased hazard (HR, 1.17; 95% CI, 1.01-1.36; p= .04).Conclusions: Certain ocular antihypertensive medications may be associated with development or progression of AMD. Their role in AMD pathogenesis should be better understood as they are considered for therapeutics in this disease.

An exploratory study to evaluate visual function endpoints in non-advanced age-related macular degeneration

Background

To prevent irreversible vision loss in age-related macular degeneration (AMD), it is critical to detect retinal dysfunction before permanent structural loss occurs. In the current study we evaluated a series of visual function tests to identify potential endpoints to detect visual dysfunction in non-advanced AMD.

Methods

A series of visual function tests were performed on 23 non-advanced AMD subjects (AREDS grade 1–4 on simplified scale) and 34 age-matched normals (AREDS grade 0). Tests included some commonly used endpoints such as ETDRS visual acuity (VA), low luminance (LL) 2.0ND ETDRS VA, MNREAD as well as newly developed tests such as the Ora-VCF™ test, Ora-tablet reading test, color sensitivity etc. Differences between the two groups were compared for each test. Test-retest repeatability and reproducibility was assessed on a subset of subjects and percent agreement was calculated.

Results

There was no difference in standard ETDRS VA between non-advanced AMD (0.06 ± 0.02 logMAR) and normal groups (0.04 ± 0.02 logMAR) (p = 0.57). LL 2.0 ETDRS VA and MNREAD showed no difference between the groups (p > 0.05). Ora-VCF™ test was significantly worse in the non-advanced AMD group compared to normals (0.67 ± 0.07 in AMD; 0.45 ± 0.04 in normals, p = 0.005). Non-advanced AMD subjects also had significantly worse reading performance using the Ora-tablet with LL 2.0ND (114.55 ± 11.22 wpm in AMD; 145.17 ± 9.55 wpm in normals p = 0.049). No significant difference between the groups was noted using other tests. Repeatability was 82% for Ora-VCF™ test and 92% for Ora-tablet LL 2.0ND reading. Reproducibility was 89% for both Ora-VCF™ test and Ora-tablet LL 2.0ND reading.

Conclusion

While there was no significant difference between non-advanced AMD and normal groups using some current common endpoints such as ETDRS VA, LL 2.0 ETDRS VA or MNREAD, Ora-VCF™ test and Ora-tablet LL 2.0ND reading tests were able to identify significant visual dysfunction in non-advanced AMD subjects. These tests show promise as endpoints for AMD studies.

Profile of retinal diseases in adult patients attending two major eye clinics in Kinshasa, the Democratic Republic of Congo

AIM

To determine the frequency and types of retinal diseases and the extend of the related visual loss in adult patients attending two public eye clinics of Kinshasa, Democratic Republic of Congo.

METHODS

Review of medical records of patients with retinal diseases seen in the major eye clinics in Kinshasa, the University Hospital of Kinshasa (UHK) and Saint Joseph Hospital (SJH), from January 2012 to December 2014. Demographics and diagnoses were retrieved and analyzed. Outcome measures were frequency and prevalence of retinal diseases, blindness and low vision.

RESULTS

A total of 40 965 patients aged 40y or older were examined during this period in both clinics. Of these, 1208 had retinal disease, giving a 3-year and an annual prevalence of 3% and 1%, respectively. Mean age was 61.7±10.7y, and 55.8% of the patients were males. Arterial hypertension (68.1%) and diabetes (43.3%) were the most common systemic comorbidities. Hypertensive retinopathy (41.8%), diabetic retinopathy (37.9%), age-related macular degeneration (AMD; 14.6%), and chorioretinitis and retinal vein occlusion (7.3% each) were the most common retinal diseases, with 3-year prevalence rates of 1.3%, 1.0%, 0.43%, and 0.21% respectively. Bilateral low vision and blindness were present in 26.8% and 8.4% of the patients at presentation. Major causes of low vision and blindness were diabetic retinopathy (14.8%), AMD (4.9%), retinal detachment (2.8%), and retinal vein occlusion (2.5%). The prevalence was significantly higher among males than females, and at the UHK than SJH.

CONCLUSION

Retinal diseases are common among Congolese adult patients attending eye clinics in Kinshasa. They cause a significant proportion of low vision and blindness.

Zinc and Autophagy in Age-Related Macular Degeneration

Zinc supplementation is reported to slow down the progression of age-related macular degeneration (AMD), but there is no general consensus on the beneficiary effect on zinc in AMD. As zinc can stimulate autophagy that is declined in AMD, it is rational to assume that it can slow down its progression. As melanosomes are the main reservoir of zinc in the retina, zinc may decrease the number of lipofuscin granules that are substrates for autophagy. The triad zinc–autophagy–AMD could explain some controversies associated with population studies on zinc supplementation in AMD as the effect of zinc on AMD may be modulated by genetic background. This aspect was not determined in many studies regarding zinc in AMD. Zinc deficiency induces several events associated with AMD pathogenesis, including increased oxidative stress, lipid peroxidation and the resulting lipofuscinogenesis. The latter requires autophagy, which is impaired. This is a vicious cycle-like reaction that may contribute to AMD progression. Promising results with zinc deficiency and supplementation in AMD patients and animal models, as well as emerging evidence of the importance of autophagy in AMD, are the rationale for future research on the role of autophagy in the role of zinc supplementation in AMD.

Differences in macular pigment optical density across four ethnicities: a comparative study

Objective:

The aim of this study is to compare macular pigment optical density levels across four different ethnicities and study its influence on ganglion cell layer and retinal nerve fibre layer thickness across these ethnicities.

Methods:

Consenting adults visiting the ophthalmology and optometry clinics for a routine eye examination without any ocular comorbidity were enrolled. Participants underwent optical coherence tomography for macular thickness, retinal nerve fibre layer thickness and ganglion cell layer thickness. The macular pigment optical density levels were determined in the dominant eye using the QuantifEye device by trained observers.

Results:

In total, 336 eyes of 336 participants with a mean age of 39.2 ± 14.4 years were included of which 103 (30%) were Caucasians, 111 (33%) were African Americans, 29 (9%) were South Asian Indians and 94 (28%) were Hispanics. The mean macular pigment optical density value across the entire study population was 0.47 ± 0.15. South Asian Indians (0.58 ± 0.16) and Hispanics (0.52 ± 0.15) had significantly higher mean macular pigment optical density values compared with Caucasians (0.41 ± 0.16) and African Americans (0.38 ± 0.15). Linear regression analysis showed that there was a significant association between ethnicities and macular pigment optical density values when adjusted for age (β coefficient = 0.31, 95% confidence interval = 0.029–0.58, p < 0.001 for South Asian Indian and Hispanic ethnic groups compared with African Americans). There were no differences in the retinal nerve fibre layer and ganglion cell layer thickness across ethnic groups. Linear regression analysis also did not reveal any significant association between macular pigment optical density levels and retinal nerve fibre layer or ganglion cell layer thickness.

Conclusion:

Caucasians and African Americans have lower macular pigment optical density compared with South Asian Indians and Hispanics. There is no clinically significant association between macular pigment optical density levels and retinal nerve fibre layer and ganglion cell layer thickness in healthy individuals across races.

Intra-Subject Variability and Diurnal Cycle of Ocular Perfusion Pressure as Characterized by Continuous Telemetry in Nonhuman Primates

Purpose

To characterize ocular perfusion pressure (OPP) fluctuations with continuous telemetry over 24-hour periods across multiple days in nonhuman primates (NHPs) to test the hypotheses that OPP differs among NHPs and that the diurnal cycle of OPP is characterized by low OPP during sleep.

Methods

We have developed and validated two implantable radiotelemetry systems that allow continuous measurement of intraocular pressure (IOP), arterial blood pressure (BP), and OPP up to 500 Hz. OPP was measured unilaterally in 12 male NHPs for periods of 38 to 412 days. IOP transducers were calibrated directly via anterior chamber manometry, and OPP was calculated continuously as central retinal artery BP minus IOP. OPP data were corrected for signal drift between calibrations and averaged hourly.

Results

OPP varied widely among animals, with daily averages ranging from ∼47 to 65 mm Hg. In eight of 12 NHPs, OPP was significantly lower during sleep compared to waking hours. In three animals, the diurnal cycle was reversed and OPP was significantly higher during sleep (P < 0.05), and one NHP showed no diurnal cycle. Day-to-day OPP variability within NHPs was the largest source of overall OPP variability, even larger than the differences between NHPs. Average daily OPP showed an unexplained ∼32-day cyclic pattern in most NHPs.

Conclusions

Average OPP varied widely and exhibited differing diurnal cycles in NHPs, a finding that matches those of prior patient studies and indicates that OPP studies in the NHP model are appropriate. Infrequent snapshot measurements of either IOP or BP are insufficient to capture true IOP, BP, and OPP and their fluctuations.

Treatment regimens for administration of anti-vascular endothelial growth factor agents for neovascular age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is one of the leading causes of permanent blindness worldwide. The current mainstay of treatment for neovascular AMD (nAMD) is intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents: aflibercept, ranibizumab, and off-label bevacizumab. Injections can be given monthly, every two or three months ('extended-fixed'), or as needed (pro re nata (PRN)). A variant of PRN is 'treat-and-extend' whereby injections are resumed if recurrence is detected and then delivered with increasing intervals. Currently, injection frequency varies among practitioners, which underscores the need to characterize an optimized approach to nAMD management.

OBJECTIVES

To investigate the effects of monthly versus non-monthly intravitreous injection of an anti-VEGF agent in people with newly diagnosed nAMD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, and three trials registers from 2004 to October 2019; checked references; handsearched conference abstracts; and contacted pharmaceutical companies to identify additional studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared different treatment regimens for anti-VEGF agents in people with newly diagnosed nAMD. We considered standard doses only (ranibizumab 0.5 mg, bevacizumab 1.25 mg, aflibercept 2.0 mg, or a combination of these).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for trial selection, data extraction, and analysis.

MAIN RESULTS

We included 15 RCTs. The total number of participants was 7732, ranging from 37 to 2457 in each trial. The trials were conducted worldwide. Of these, six trials exclusively took place in the US, and three included centers from more than one country. Eight trials were at high risk of bias for at least one domain and all trials had at least one domain at unclear risk of bias. Seven trials (3525 participants) compared a PRN regimen with a monthly injection regimen, of which five trials delivered four to eight injections using standard PRN and three delivered nine or 10 injections using a treat-and-extend regimen in the first year. The overall mean change in best-corrected visual acuity (BCVA) at one year was +8.8 letters in the monthly injection group. Compared to the monthly injection, there was moderate-certainty evidence that the mean difference (MD) in BCVA change at one year for the standard PRN subgroup was -1.7 letters (95% confidence interval (CI) -2.8 to -0.6; 4 trials, 2299 participants), favoring monthly injections. There was low-certainty evidence of a similar BCVA change with the treat-and-extend subgroup (0.5 letters, 95% CI -3.1 to 4.2; 3 trials, 1226 participants). Compared to monthly injection, there was low-certainty evidence that fewer participants gained 15 or more lines of vision with standard PRN treatment at one year (risk ratio (RR) 0.87, 95% CI 0.76 to 0.99; 4 trials, 2299 participants) and low-certainty evidence of a similar gain with treat-and-extend versus monthly regimens (RR 1.11, 95% CI 0.91 to 1.36; 3 trials, 1169 participants). The mean change in central retinal thickness was a decrease of -166 μm in the monthly injection group; the MD compared with standard PRN was 21 μm (95% CI 6 to 32; 4 trials, 2215 participants; moderate-certainty evidence) and with treat-and extend was 22 μm (95% CI 37 to -81 μm; 2 trials, 635 participants; low-certainty evidence), in favor of monthly injection. Only one trial (498 participants) measured quality of life and reported no evidence of a difference between regimens, but data could not be extracted (low-certainty evidence). Both PRN regimens (standard and 'treat-and-extend') used fewer injections than monthly regimens (standard PRN: MD -4.6 injections, 95% CI -5.4 to -3.8; 4 trials, 2336 participants; treat-and-extend: -2.4 injections, 95% CI -2.7 to -2.1 injections; moderate-certainty evidence for both comparisons). Two trials provided cost data (1105 participants, trials conducted in the US and the UK). They found that cost differences between regimens were reduced if bevacizumab rather than aflibercept or ranibizumab were used, since bevacizumab was less costly (low-certainty evidence). PRN regimens were associated with a reduced risk of endophthalmitis compared with monthly injections (Peto odds ratio (OR) 0.13, 95% CI 0.04 to 0.46; 6 RCTs, 3175 participants; moderate-certainty evidence). Using data from all trials included in this review, we estimated the risk of endophthalmitis with monthly injections to be 8 in every 1000 people per year. The corresponding risk for people receiving PRN regimens was 1 in every 1000 people per year (95% CI 0 to 4). Three trials (1439 participants) compared an extended-fixed regimen (number of injections reported in only one large trial: 7.5 in one year) with monthly injections. There was moderate-certainty evidence that BCVA at one year was similar for extended-fixed and monthly injections (MD in BCVA change compared to extended-fixed group: -1.3 letters, 95% CI -3.9 to 1.3; RR of gaining 15 letters or more: 0.94, 95% CI 0.80 to 1.10). The change in central retinal thickness was a decrease of 137 μm in the monthly group; the MD with the extended-fixed group was 8 μm (95% CI -11 to 27; low-certainty evidence). The frequency of endophthalmitis was lower in the extended-fixed regimen compared to the monthly group, but this estimate was imprecise (RR 0.19, 95% CI 0.03 to 1.11; low-certainty evidence). If we assumed a risk of 8 cases of endophthalmitis in 1000 people receiving monthly injections over one year, then the corresponding risk with extended-fixed regimen was 2 in 1000 people (95% CI 0 to 9). Other evidence comparing different extended-fixed or PRN regimens yielded inconclusive results.

AUTHORS' CONCLUSIONS

We found that, at one year, monthly regimens are probably more effective than PRN regimens using seven or eight injections in the first year, but the difference is small and clinically insignificant. Endophthalmitis is probably more common with monthly injections and differences in costs between regimens are higher if aflibercept or ranibizumab are used compared to bevacizumab. This evidence only applies to settings in which regimens are implemented as described in the trials, whereas undertreatment is likely to be common in real-world settings. There are no data from RCTs on long-term effects of different treatment regimens.

COLORADO AGE-RELATED MACULAR DEGENERATION REGISTRY: Design and Clinical Risk Factors of the Cohort

PURPOSE

To study new and existing risk factors related to age-related macular degeneration (AMD) phenotypes in a Colorado cohort.

METHODS

Age-related macular degeneration was categorized into early, intermediate, or advanced forms. Controls (n = 180) were patients with cataract and no AMD. Demographic and clinical data were gathered by patient interview and verified by chart review. Image data were reviewed by vitreoretinal specialists. Statistical analysis included univariable and multivariate logistic regression analysis (P < 0.05).

RESULTS

Among the 456 patients with AMD, 157 (34.4%), 80 (17.6%), and 219 (48.0%) had the early/intermediate, geographic atrophy, and neovascular forms of the disease, respectively. Adjusted for age, African-American race was associated with a reduced risk of early/intermediate (adjusted odds ratio [AOR] = 0.08, confidence interval [CI] = 0.01-0.67) and neovascular AMD (AOR = 0.15, CI = 0.03-0.72). A family history of AMD was a risk factor for early/intermediate (AOR = 4.08, CI = 2.30-7.25), geographic atrophy (AOR = 8.62, CI = 3.77-19.7), and neovascular AMD (AOR = 3.76, CI = 2.16-6.56). A history of asthma was related to the early/intermediate form of AMD (AOR = 2.34, CI = 1.22-4.46).

CONCLUSION

Studying AMD in specific populations may reveal novel risk factors such as our finding of a relationship between asthma history and AMD.

Progression from Early/Intermediate to Advanced Forms of Age-Related Macular Degeneration in a Large UK Cohort: Rates and Risk Factors

PURPOSE

To estimate rates and risk factors for progression to geographic atrophy (GA) or choroidal neovascularization (CNV) among eyes diagnosed with early or intermediate age-related macular degeneration (AMD) in clinical practice.

DESIGN

Retrospective cohort analysis of a multicenter electronic medical record (EMR) database from the United Kingdom.

PARTICIPANTS

Patients aged 50 years or more with diagnosis of early/intermediate AMD in at least 1 eye (the study eye) and no evidence of CNV or GA in the study eye, from 10 clinical sites using the EMR.

METHODS

Anonymized data for 40 543 patients with a diagnosis of early/intermediate AMD were extracted between October 2000 and February 2016 from EMR database records held in the 10 sites. A sample of records randomly selected from each center was used to validate disease definitions. Records were analyzed by subgroup, based on the AMD status of the fellow eye. Multivariate Cox regression models identified other predictors of disease progression.

MAIN OUTCOME MEASURES

Progression rate (per 100 person-years) to GA or CNV in study eyes with early/intermediate AMD by fellow eye status and identified risk factors for progression.

RESULTS

Study eyes with early/intermediate AMD and a diagnosis of CNV in the fellow eye progressed to CNV fastest (at a rate of 15.2 per 100 person-years), and those with a diagnosis of GA in the fellow eye progressed to GA fastest (11.2 per 100 person-years), compared with the rates per 100 person-years of progression to CNV (3.2-11.9) or GA (2.0-7.8) in the other subgroups. In individuals with bilateral early/intermediate AMD, rates of progression to GA or CNV were 2.0 and 3.2 per 100 person-years, respectively. In the multivariate model, age, female sex, and cardiovascular disease were associated with an increased risk for progression to advanced AMD, whereas diabetes and glaucoma were associated with a decreased rate of progression (hazard ratios, 0.45 and 0.64, respectively).

CONCLUSIONS

Progression to GA or CNV was observed frequently in eyes with early/intermediate AMD, with the status of the fellow eye affecting the rate of progression. Novel associations with risk factors were observed and require replication in other cohorts.

Racial Differences in Age-Related Macular Degeneration and Associated Anti-Vascular Endothelial Growth Factor Intravitreal Injections among Medicare Beneficiaries

PURPOSE

To determine racial and ethnic differences in age-related macular degeneration (AMD) and the use of anti-vascular endothelial growth factor (VEGF) injections for AMD among United States Medicare beneficiaries.

DESIGN

Cross-sectional Medicare database study.

PARTICIPANTS

2014 United States fee-for-service Medicare beneficiaries.

METHODS

The 2014 Medicare 5% Limited Data Set Standard Analytic Files, representing a 5% sample of approximately 28 238 660 fee-for-service Medicare beneficiaries 65 years of age and older, were used to identify all beneficiaries who received a diagnosis of AMD and who received intravitreal anti-VEGF injections for AMD, stratified by race, gender, and age. Logistic regression analysis determined racial differences in the likelihood of an AMD diagnosis and anti-VEGF treatment for AMD, adjusted for age and gender.

MAIN OUTCOME MEASURES

Number of beneficiaries diagnosed with AMD in 2014 and number of beneficiaries who received anti-VEGF intravitreal injections for AMD in 2014.

RESULTS

Among approximately 28 238 660 Medicare beneficiaries in 2014, 2 210 000 (7.8%) were diagnosed with AMD. Among beneficiaries with an AMD diagnosis, 360 640 (16.3%) received 1 or more anti-VEGF intravitreal injection for AMD. After adjustment for age and gender, an AMD diagnosis was 74% less likely in African Americans (odds ratio [OR] 0.26; 95% confidence interval [CI], 0.25-0.27), 44% less likely in Latinos (OR, 0.56; 95% CI, 0.53-0.60), and 19% less likely in Asian Americans (OR, 0.81; 95% CI, 0.77-0.85) than in white beneficiaries. Anti-VEGF injections for AMD were 86% less likely in African Americans (OR, 0.14; 95% CI, 0.12-0.16), 61% less likely in Latinos (OR, 0.39; 95% CI, 0.33-0.45), and 48% less likely in Asian Americans (OR, 0.52; 95% CI, 0.46-0.60) than in whites. Race- and gender-adjusted odds of both AMD and the use of anti-VEGF agents for AMD increased with age (P < 0.001).

CONCLUSIONS

There are racial differences in the prevalence of an AMD diagnosis and in receiving anti-VEGF injections for AMD among fee-for-service Medicare beneficiaries 65 years of age or older. African Americans, Latinos, and Asian Americans were 19% to 74% less likely to have a diagnosis of AMD and were 48% to 86% less likely to receive an anti-VEGF intravitreal injection for AMD than in whites.

Conbercept for patients with age-related macular degeneration: a systematic review

Background

Conbercept is a novel vascular endothelial growth factor (VEGF) inhibitor for the treatment of wet age-related macular degeneration (AMD). This systematic review aims to assess the efficacy and safety of conbercept in the treatment of wet AMD.

Methods

PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, VIP database, and Wanfang database were searched from their earliest records to June 2017. We included randomized controlled trials (RCTs) evaluating the efficacy and safety of conbercept in wet AMD patients. Outcomes included the mean changes from baseline in best-corrected visual acuity (BCVA) score (primary outcome), central retinal thickness (CRT), plasma level of vascular endothelial growth factor (VEGF) over time, and the incidence of adverse events (AEs).

Results

Eighteen RCTs (1285 participants) were included in this systematic review. Conbercept might improve BCVA compared to triamcinolone acetonide [MD = 0.11, 95% CI (0.08, 0.15)], and reduce CRT compared to the other four therapies (conservative treatment, ranibizumab, transpupillary thermotherapy, and triamcinolone acetonide). The incidence of AEs in patients receiving conbercept was significantly lower than those receiving triamcinolone acetonide [RR = 0.25, 95% CI (0.09–0.72)], but was similar to the other therapies. Conbercept seemed to be more effective than ranibizumab in lowering the plasma level of VEGF [MD = − 15.86, 95% CI (− 23.17, − 8.55)].

Conclusions

Current evidence shows that conbercept is a promising option for the treatment of wet AMD. Nevertheless, further studies are required to compare the efficacy, long-term safety and cost-effectiveness between conbercept and other anti-VEGF agents in different populations.

Electronic supplementary material

The online version of this article (10.1186/s12886-018-0807-1) contains supplementary material, which is available to authorized users.

Updates on the Epidemiology of Age-Related Macular Degeneration

This meta-analysis reports on current estimates of the prevalence of age-related macular degeneration (AMD) based on a review of recent meta-analyses and literature research. Within an age of 45-85 years, global prevalences of any AMD, early AMD, and late AMD were 8.7% [95% credible interval (CrI), 4.3‒17.4], 8.0% (95% CrI, 4.0‒15.5), and 0.4% (95% CrI, 0.2-0.8). Early AMD was more common in individuals of European ancestry (11.2%) than in Asians (6.8%), whereas prevalence of late AMD did not differ significantly. AMD of any type was less common in individuals of African ancestry. The number of individuals with AMD was estimated to be 196 million (95% CrI, 140‒261) in 2020 and 288 million (95% CrI, 205‒399) in 2040. The worldwide number of persons blind (presenting visual acuity < 3/60) or with moderate to severe vision impairment (MSVI; presenting visual acuity < 6/18 to 3/60 inclusive) due to macular disease in 2010 was 2.1 million [95% uncertainty interval (UI), 1.9‒2.7] individuals out of 32.4 million individuals blind and 6.0 million (95% UI, 5.2‒8.1) persons out of 191 million people with MSVI. Age-standardized prevalence of macular diseases as cause of blindness in adults aged 50+ years worldwide decreased from 0.2% (95% UI, 0.2‒0.2) in 1990 to 0.1% (95% UI, 0.1‒0.2) in 2010; as cause for MSVI, it remained mostly unchanged (1990: 0.4%; 95% UI, 0.3‒0.5; 2010: 0.4%; 95% UI, 0.4‒0.6), with no significant sex difference. In 2015, AMD was the fourth most common cause of blindness globally (in approximately 5.8% of blind individuals) and third most common cause for MSVI (3.9%). These data show the globally increasing importance of AMD.

Automated Brightness and Contrast Adjustment of Color Fundus Photographs for the Grading of Age-Related Macular Degeneration

Purpose

The purpose of this study was to develop an algorithm to automatically standardize the brightness, contrast, and color balance of digital color fundus photographs used to grade AMD and to validate this algorithm by determining the effects of the standardization on image quality and disease grading.

Methods

Seven-field color photographs of patients (>50 years) with any stage of AMD and a control group were acquired at two study sites, with either the Topcon TRC-50DX or Zeiss FF-450 Plus cameras. Field 2 photographs were analyzed. Pixel brightness values in the red, green, and blue (RGB) color channels were adjusted in custom-built software to make the mean brightness and contrast of the images equal to optimal values determined by the Age-Related Eye Disease Study (AREDS) 2 group.

Results

Color photographs of 370 eyes were analyzed. We found a wide range of brightness and contrast values in the images at baseline, even for those taken with the same camera. After processing, image brightness variability (brightest image–dimmest image in a color channel) was reduced 69-fold, 62-fold, and 96-fold for the RGB channels. Contrast variability was reduced 6-fold, 8-fold, and 13-fold, respectively, after adjustment. Of the 23% images considered nongradable before adjustment, only 5.7% remained nongradable.

Conclusions

This automated software enables rapid and accurate standardization of color photographs for AMD grading.

Translational Relevance

This work offers the potential to be the future of assessing and grading AMD from photos for clinical research and teleimaging.

The Age-Related Eye Disease 2 Study: Micronutrients in the Treatment of Macular Degeneration

Age-related macular degeneration (AMD) is one of the leading causes of vision loss in the elderly. With an increasingly aged population worldwide, the need for the prevention of AMD is rising. Multiple studies investigating AMD with the use of animal models and cell culture have identified oxidative stress-related retinal damage as an important contributing factor. In general, diet is an excellent source of the antioxidants, vitamins, and minerals necessary for healthy living; moreover, the general public is often receptive to recommendations made by physicians and health care workers regarding diet and supplements as a means of empowering themselves to avoid common and worrisome ailments such as AMD, which has made epidemiologists and clinicians enthusiastic about dietary intervention studies. A wide variety of nutrients, such as minerals, vitamins, ω-3 (n-3) fatty acids, and various carotenoids, have been associated with reducing the risk of AMD. Initial results from the Age-Related Eye Disease Study (AREDS) indicated that supplementation with antioxidants (β-carotene and vitamins C and E) and zinc was associated with a reduced risk of AMD progression. The AREDS2 follow-up study, designed to improve upon the earlier formulation, tested the addition of lutein, zeaxanthin, and ω-3 fatty acids. In this review, we examine the science behind the nutritional factors included in these interventional studies and the reasons for considering their inclusion to lower the rate of AMD progression.

Structural and molecular changes in the aging choroid: implications for age-related macular degeneration

Age-related macular degeneration (AMD) is a devastating disease-causing vision loss in millions of people around the world. In advanced stages of disease, death of photoreceptor cells, retinal pigment epithelial cells, and choroidal endothelial cells (CECs) are common. Loss of endothelial cells of the choriocapillaris is one of the earliest detectable events in AMD, and, because the outer retina relies on the choriocapillaris for metabolic support, this loss may be the trigger for progression to more advanced stages. Here we highlight evidence for loss of CECs, including changes to vascular density within the choriocapillaris, altered abundance of CEC markers, and changes to overall thickness of the choroid. Furthermore, we review the key components and functions of the choroid, as well as Bruch's membrane, both of which are vital for healthy vision. We discuss changes to the structure and molecular composition of these tissues, many of which develop with age and may contribute to AMD pathogenesis. For example, a crucial event that occurs in the aging choriocapillaris is accumulation of the membrane attack complex, which may result in complement-mediated CEC lysis, and may be a primary cause for AMD-associated choriocapillaris degeneration. The actions of elevated monomeric C-reactive protein in the choriocapillaris in at-risk individuals may also contribute to the inflammatory environment in the choroid and promote disease progression. Finally, we discuss the progress that has been made in the development of AMD therapies, with a focus on cell replacement.

Melanins and melanogenesis: from pigment cells to human health and technological applications

During the past decade, melanins and melanogenesis have attracted growing interest for a broad range of biomedical and technological applications. The burst of polydopamine-based multifunctional coatings in materials science is just one example, and the list may be expanded to include melanin thin films for organic electronics and bioelectronics, drug delivery systems, functional nanoparticles and biointerfaces, sunscreens, environmental remediation devices. Despite considerable advances, applied research on melanins and melanogenesis is still far from being mature. A closer intersectoral interaction between research centers is essential to raise the interests and increase the awareness of the biomedical, biomaterials science and hi-tech sectors of the manifold opportunities offered by pigment cells and related metabolic pathways. Starting from a survey of biological roles and functions, the present review aims at providing an interdisciplinary perspective of melanin pigments and related pathway with a view to showing how it is possible to translate current knowledge about physical and chemical properties and control mechanisms into new bioinspired solutions for biomedical, dermocosmetic, and technological applications.

Risk factors and biomarkers of age-related macular degeneration

A biomarker can be a substance or structure measured in body parts, fluids or products that can affect or predict disease incidence. As age-related macular degeneration (AMD) is the leading cause of blindness in the developed world, much research and effort has been invested in the identification of different biomarkers to predict disease incidence, identify at risk individuals, elucidate causative pathophysiological etiologies, guide screening, monitoring and treatment parameters, and predict disease outcomes. To date, a host of genetic, environmental, proteomic, and cellular targets have been identified as both risk factors and potential biomarkers for AMD. Despite this, their use has been confined to research settings and has not yet crossed into the clinical arena. A greater understanding of these factors and their use as potential biomarkers for AMD can guide future research and clinical practice. This article will discuss known risk factors and novel, potential biomarkers of AMD in addition to their application in both academic and clinical settings.

The prevalence and risk factors for age-related macular degeneration in rural-urban India, Sankara Nethralaya Rural-Urban Age-related Macular degeneration study, Report No. 1

PurposeTo report the age- and gender-adjusted prevalence rates of early and late age-related maculopathy (ARM) and associated risk factors in rural and urban Indian population.MethodsA population-based cross-sectional study was carried out in South India between 2009 and 2011. Of the 6617 subjects ≥60 years enumerated ones, 5495 (83.04%) participated in the eye examination. A detailed history including data on demographic, socioeconomic, and ocular history was obtained. Participants underwent detailed ophthalmic evaluation including 30° 3-field photograph as per Age-Related Eye Disease Study protocol. The ARM was graded according to the International ARM Epidemiological Study Group.ResultsAge- and gender-adjusted prevalence of early ARM was 20.91% (20.86-20.94) in the rural population and 16.37% (16.32-16.42) in the urban population. Similarly, the prevalence of late ARM was 2.26% (2.24-2.29) and 2.32% (2.29-2.34) in the rural and urban population, respectively. In both rural and urban populations, risk factors that were related to both early and late ARM were age, per year increase (OR, range 1.00-1.08); middle socioeconomic status (OR, range 1.05-1.83); and smokeless tobacco (OR, range 1.11-2.21). Protective factor in both was the presence of diabetes mellitus in all ARM (OR, range 0.34-0.83). Risk factors, only in the rural arm, were female gender (OR, range 1.06-1.64), past smoker (OR, 1.14), and serum low-density lipoprotein cholesterol level (OR, 1.03).ConclusionsThe study reports smokessless tobacco as a risk factor for both early and late ARM and identified a higher prevalence of early ARM in the rural population compared with urban population.

Geo-Epidemiology of Age-Related Macular Degeneration: New Clues Into the Pathogenesis

PURPOSE

To evaluate the demographic, geographic, and race-related variables that account for geographic variability in prevalence rates of age-related macular degeneration (AMD).

DESIGN

Systematic review, meta-regression, and decision-tree analysis.

METHODS

A systematic literature review of PubMed, Medline, Web of Science, and Embase databases identified population-based studies on the prevalence of AMD published before May 2014. Only population-based studies that took place in a spatially explicit geographic area that could be geolocalized, and used retinal photographs and standardized grading classifications, were included. Latitude and longitude data (geolocalization) and the mean annual insolation for the area where survey took place were obtained. Age-standardized prevalence rates across studies were estimated using the direct standardization method. Correlations between the prevalence of AMD and longitude and latitude were obtained by regression analysis. A hierarchical Bayesian meta-regression approach was used to assess the association between the prevalence of AMD and other relevant factors. We further investigated the interplay between location and these factors on the prevalence of AMD using regression based on conditional-inference decision trees.

RESULTS

We observed significant inverse correlations between latitude or longitude, and crude or age-standardized prevalence rates, of early and late AMD (P < .001). Metaregression analysis showed that insolation, latitude, longitude, age, and race have a significant effect on the prevalence rates of early and late AMD (P < .001). Decision-tree analysis identified that the most important predictive variable was race for early AMD (P = .002) and insolation for late AMD (P = .001).

CONCLUSIONS

Geographic position and insolation are key factors in the prevalence of AMD.

Combination of Aflibercept and Bromfenac Therapy in Age-Related Macular Degeneration: A Pilot Study Aflibercept and Bromfenac in AMD

BACKGROUND Among many protocols for treatment of exudative AMD, combined therapy of anti-VEGF agents and non-steroidal anti-inflammatory drugs (NSAIDs) seems to be an ideal alternative to monotherapy based on ranibizumab or bevacizumab. The aim of this study was to evaluate the effectiveness of aflibercept and bromfenac in the treatment of exudative AMD. MATERIAL AND METHODS The study was conducted on a group of 27 patients with exudative AMD who were administered intravitreal aflibercept and topical bromfenac (study group) once a month. Additional injections were administered up to 3 months after the third administration, depending on response to treatment. The control group consisted of subjects treated with aflibercept only. Visual acuity and anatomical outcomes in optical coherence tomography (OCT) were assessed at baseline visit, 4 months after the first dose, and 6 months after the start of the treatment. RESULTS Visual acuity improved over time in the study group and the differences between the groups were statistically significant. No statistically significant differences were found in OCT parameters. CONCLUSIONS Combined therapy of aflibercept and bromfenac in the treatment of wet AMD is more effective than single aflibercept therapy.

Susceptibility to N-methyl-N-nitrosourea-induced retinal degeneration in different rat strains

To evaluate the potential role of genetic background in the susceptibility to retinal degeneration induced by N-methyl-N-nitrosourea (MNU), female rats of the Sprague-Dawley (SD), Long-Evans (LE) and Copenhagen (CH) strains were administered 50 mg/kg MNU or saline at 7 weeks of age. Retina morphology and morphometric analysis of all rats was performed 7 days after MNU administration. Atrophy of both the peripheral and central outer retina occurred in all rat strains exposed to MNU. Decreased photoreceptor cell ratio and increased retinal damage ratio were observed. The severities of the retinal atrophy were similar among all three rat strains. In conclusion, MNU-induced photoreceptor degeneration developed consistently in all three strains regardless of the absence (SD rats) or presence (LE and CH rats) of melanin in the retina, suggesting that genetic and melanin factors did not affect photoreceptor cell death after MNU.

Correlation between neovascular lesion type and clinical characteristics of nonneovascular fellow eyes in patients with unilateral, neovascular age-related macular degeneration

PURPOSE

To investigate the association between the type of neovascularization (NV) and the clinical characteristics of nonneovascular fellow eyes in patients with unilateral, neovascular age-related macular degeneration.

METHODS

Eighty-three patients with treatment-naive, unilateral, neovascular age-related macular degeneration were retrospectively analyzed. Neovascular lesions were classified using both fluorescein angiography and optical coherence tomography as Type 1 (subretinal pigment epithelium), 2 (subretinal), 3 (intraretinal), or mixed NV. The associations between NV lesion type and baseline clinical and imaging characteristics of the fellow eye, including central geographic atrophy, noncentral geographic atrophy, pigmentary changes, soft drusen, cuticular drusen, reticular pseudodrusen, and subfoveal choroidal thickness, were examined. Subfoveal choroidal thickness was defined as thin if thickness was <120 μm.

RESULTS

In the fellow eyes of patients with treatment-naive, unilateral, neovascular age-related macular degeneration, Type 3 NV had an increased adjusted odds ratio of reticular pseudodrusen (15.361, P < 0.001) and thin subfoveal choroidal thickness (21.537, P < 0.001) as well as a tendency toward an increased adjusted odds ratio of central geographic atrophy (4.775, P = 0.028). Fellow eyes of patients with Type 1 NV showed a decreased adjusted odds ratio of reticular pseudodrusen (0.233, P = 0.007) and thin subfoveal choroidal thickness (0.080, P = 0.005).

CONCLUSION

In patients with unilateral, neovascular age-related macular degeneration, certain nonneovascular features of the fellow eye correlate with the NV lesion composition based on type, as anatomically classified utilizing both fluorescein angiography and optical coherence tomography. Patients with Type 3 NV were more likely to have reticular pseudodrusen and/or thin subfoveal choroidal thickness in the fellow eye compared with those with Type 1 NV. Patients with Type 3 NV also showed a trend toward increased central geographic atrophy in the fellow eye.

Ancestry of the Timorese: age-related macular degeneration associated genotype and allele sharing among human populations from throughout the world

We observed that the third leading cause of blindness in the world, age-related macular degeneration (AMD), occurs at a very low documented frequency in a population-based cohort from Timor-Leste. Thus, we determined a complete catalog of the ancestry of the Timorese by analysis of whole exome chip data and haplogroup analysis of SNP genotypes determined by sequencing the Hypervariable I and II regions of the mitochondrial genome and 17 genotyped YSTR markers obtained from 535 individuals. We genotyped 20 previously reported AMD-associated SNPs in the Timorese to examine their allele frequencies compared to and between previously documented AMD cohorts of varying ethnicities. For those without AMD (average age > 55 years), genotype and allele frequencies were similar for most SNPs with a few exceptions. The major risk allele of HTRA1 rs11200638 (10q26) was at a significantly higher frequency in the Timorese, as well as 3 of the 5 protective CFH (1q32) SNPs (rs800292, rs2284664, and rs12066959). Additionally, the most commonly associated AMD-risk SNP, CFH rs1061170 (Y402H), was also seen at a much lower frequency in the Korean and Timorese populations than in the assessed Caucasian populations (C ~7 vs. ~40%, respectively). The difference in allele frequencies between the Timorese population and the other genotyped populations, along with the haplogroup analysis, also highlight the genetic diversity of the Timorese. Specifically, the most common ancestry groupings were Oceanic (Melanesian and Papuan) and Eastern Asian (specifically Han Chinese). The low prevalence of AMD in the Timorese population (2 of 535 randomly selected participants) may be due to the enrichment of protective alleles in this population at the 1q32 locus.

Extracting Primary Open-Angle Glaucoma from Electronic Medical Records for Genetic Association Studies

Electronic medical records (EMRs) are being widely implemented for use in genetic and genomic studies. As a phenotypic rich resource, EMRs provide researchers with the opportunity to identify disease cohorts and perform genotype-phenotype association studies. The Epidemiologic Architecture for Genes Linked to Environment (EAGLE) study, as part of the Population Architecture using Genomics and Epidemiology (PAGE) I study, has genotyped more than 15,000 individuals of diverse genetic ancestry in BioVU, the Vanderbilt University Medical Center’s biorepository linked to a de-identified version of the EMR (EAGLE BioVU). Here we develop and deploy an algorithm utilizing data mining techniques to identify primary open-angle glaucoma (POAG) in African Americans from EAGLE BioVU for genetic association studies. The algorithm described here was designed using a combination of diagnostic codes, current procedural terminology billing codes, and free text searches to identify POAG status in situations where gold-standard digital photography cannot be accessed. The case algorithm identified 267 potential POAG subjects but underperformed after manual review with a positive predictive value of 51.6% and an accuracy of 76.3%. The control algorithm identified controls with a negative predictive value of 98.3%. Although the case algorithm requires more downstream manual review for use in large-scale studies, it provides a basis by which to extract a specific clinical subtype of glaucoma from EMRs in the absence of digital photographs.