The prevalence and analysis of risk factors for age-related macular degeneration: 18-year follow-up data from the Speedwell eye study, United Kingdom

The Role of Reactive Oxygen Species in Age-Related Macular Degeneration: A Comprehensive Review of Antioxidant Therapies

This review article delves into the intricate roles of reactive oxygen species (ROS) in the pathogenesis of age-related macular degeneration (AMD). It presents a detailed analysis of the oxidative stress mechanisms that contribute to the development and progression of these diseases. The review systematically explores the dual nature of ROS in ocular physiology and pathology, underscoring their essential roles in cellular signaling and detrimental effects when in excess. In the context of AMD, the focus is on the oxidative impairment in the retinal pigment epithelium and Bruch's membrane, culminating in the deterioration of macular health. Central to this review is the evaluation of various antioxidant strategies in the prevention and management of AMD. It encompasses a wide spectrum of antioxidants, ranging from dietary nutrients like vitamins C and E, lutein, and zeaxanthin to pharmacological agents with antioxidative properties. The review also addresses novel therapeutic approaches, including gene therapy and nanotechnology-based delivery systems, aiming to enhance antioxidant defense mechanisms in ocular tissues. The article concludes by synthesizing current research findings, clinical trial data, and meta-analyses to provide evidence-based recommendations. It underscores the need for further research to optimize antioxidant therapies, considering individual patient factors and disease stages. This comprehensive review thus serves as a valuable resource for clinicians, researchers, and healthcare professionals in ophthalmology, offering insights into the potential of antioxidants in mitigating the burden of AMD.

Correlation Between C-Reactive Protein and Lipid Analytes in Dry Age-Related Macular Degeneration: A Retrospective Study

INTRODUCTION

To date few studies have investigated the correlation between inflammatory markers and lipoproteins in the serum of age-related macular degeneration (AMD) patients, often reporting conflicting findings. This study aimed to investigate the correlation between lipid analytes and C-reactive protein (CRP) levels in individuals diagnosed with dry AMD.

METHODS

A standard clinical lipid panel (total cholesterol, triglycerides, high-density lipoprotein [HDL], and low-density lipoproteins) and CRP laboratory results were retrospectively collected from the medical records of patients with dry AMD and age- and sex-matched controls.

RESULTS

The study included 90 patients with dry AMD and 270 patients without AMD. In univariate analysis, CRP showed a higher mean value in cases than in controls. After adjusting for age and sex, CRP and triglyceride levels showed significant differences between cases and controls. Pearson's correlation analysis revealed a significant negative correlation between CRP and HDL levels in the dry AMD group (n=90). Other lipid analytes showed no significant correlations with CRP.

CONCLUSION

Our findings add to the growing body of evidence linking inflammation to AMD. Although it is unclear whether changes in serum CRP and triglyceride levels are the causes or effects, monitoring both analytes may be beneficial as an early disease predictor, especially in individuals with a family history of AMD. The negative correlation between CRP and HDL (i.e., inflammation and good cholesterol) may be targeted for future therapies.

Systemic Dyslipidemia in Age-related Macular Degeneration: An Updated Systematic Review and Meta-analysis

Topic

Though lipid and cholesterol dyshomeostasis is thought to contribute to the pathogenesis of age-related macular degeneration (AMD), there is no consensus regarding which elements of systemic lipid homeostasis are perturbed in AMD. In this systematic review and meta-analysis, an update to that performed by Wang et al in 2016, we characterized serum lipoprotein profiles in patients with AMD and its various stages.

Clinical Relevance

These findings may identify novel therapeutic approaches for AMD, a leading cause of blindness among older adults in the industrialized world.

Methods

We used MEDLINE, Embase, and Web of Science to identify articles from database inception to May 2022 that reported blood/serum levels of lipid subspecies (triglycerides [TGs], total cholesterol [TC], low-density lipoprotein [LDL], and high-density lipoprotein [HDL]) in patients with AMD compared with controls. We meta-analyzed the data by generating multilevel random-effects models using restricted maximum likelihood estimation.

Results

Our updated meta-analysis included 56 studies, almost 3 times as many studies as the 2016 meta-analysis with a total of 308 188 participants. There were no significant differences in serum TG, TC, LDL, or HDL between patients with AMD and non-AMD controls. Given significant heterogeneity, we performed subanalyses specifically in patients with early to intermediate nonexudative AMD, advanced nonexudative AMD, and advanced exudative AMD. Compared with non-AMD controls, patients with early to intermediate nonexudative AMD had significantly lower serum TG (standardized mean difference [SMD]: -0.03; 95% confidence interval [95% CI]: -0.06 to -0.01) and higher serum HDL (SMD: 0.07; 95% CI: 0.04-0.11). Patients with advanced exudative AMD had significantly higher serum LDL (SMD: 0.33; 95% CI: 0.04-0.62) compared with non-AMD controls. There were no other significant differences identified.

Conclusion

We found that there is significant heterogeneity in systemic lipoproteins in patients with AMD compared with non-AMD controls. The specific pattern of lipid dyshomeostasis appeared to be distinct based on AMD stage. These findings highlight both the underlying heterogeneity of AMD as well as the presence of distinct pathophysiological mechanisms involved at different stages or subtypes of AMD and may inform the development of novel therapeutic approaches.

Financial Disclosures

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

Artificial Intelligence Analysis of Biofluid Markers in Age-Related Macular Degeneration: A Systematic Review

This systematic review explores the use of artificial intelligence (AI) in the analysis of biofluid markers in age-related macular degeneration (AMD). We detail the accuracy and validity of AI in diagnostic and prognostic models and biofluid markers that provide insight into AMD pathogenesis and progression. This review was conducted in accordance with the Preferred Reporting Items for a Systematic Review and Meta-analysis guidelines. A comprehensive search was conducted across 5 electronic databases including Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, EMBASE, Medline, and Web of Science from inception to July 14, 2021. Studies pertaining to biofluid marker analysis using AI or bioinformatics in AMD were included. Identified studies were assessed for risk of bias and critically appraised using the Joanna Briggs Institute Critical Appraisal tools. A total of 10,264 articles were retrieved from all databases and 37 studies met the inclusion criteria, including 15 cross-sectional studies, 15 prospective cohort studies, five retrospective cohort studies, one randomized controlled trial, and one case–control study. The majority of studies had a general focus on AMD (58%), while neovascular AMD (nAMD) was the focus in 11 studies (30%), and geographic atrophy (GA) was highlighted by three studies. Fifteen studies examined disease characteristics, 15 studied risk factors, and seven guided treatment decisions. Altered lipid metabolism (HDL-cholesterol, total serum triglycerides), inflammation (c-reactive protein), oxidative stress, and protein digestion were implicated in AMD development and progression. AI tools were able to both accurately differentiate controls and AMD patients with accuracies as high as 87% and predict responsiveness to anti-VEGF therapy in nAMD patients. Use of AI models such as discriminant analysis could inform prognostic and diagnostic decision-making in a clinical setting. The identified pathways provide opportunity for future studies of AMD development and could be valuable in the advancement of novel treatments.

Not All Stressors Are Equal: Mechanism of Stressors on RPE Cell Degeneration

Age-related macular degeneration (AMD) is a major cause of irreversible blindness among the elderly population. Dysfunction and degeneration of the retinal pigment epithelial (RPE) layer in the retina underscore the pathogenesis of both dry and wet AMD. Advanced age, cigarette smoke and genetic factors have been found to be the prominent risk factors for AMD, which point to an important role for oxidative stress and aging in AMD pathogenesis. However, the mechanisms whereby oxidative stress and aging lead to RPE cell degeneration are still unclear. As cell senescence and cell death are the major outcomes from oxidative stress and aging, here we review the mechanisms of RPE cell senescence and different kinds of cell death, including apoptosis, necroptosis, pyroptosis, ferroptosis, with an aim to clarify how RPE cell degeneration could occur in response to AMD-related stresses, including H₂O₂, 4-Hydroxynonenal (4-HNE), N-retinylidene-N-retinyl-ethanolamine (A2E), Alu RNA and amyloid β (Aβ). Besides those, sodium iodate (NaIO₃) induced RPE cell degeneration is also discussed in this review. Although NaIO₃ itself is not related to AMD, this line of study would help understand the mechanism of RPE degeneration.

Systemic levels of C-reactive protein in patients with age-related macular degeneration: A systematic review with meta-analyses

Ageing of the retina is associated with the gradual accumulation of basal deposits and the formation of drusen. However, in some individuals this process is exacerbated and causes development of age-related macular degeneration. Late features of age-related macular degeneration include geographic atrophy of the neuroretina or choroidal neovascularization. Such changes lead to blurred vision, metamorphopsia, and scotoma, and is the leading cause of vision loss in developed countries. Chronic low-grade inflammation has been investigated because of its relationship to ageing and its role in the gap between chronological and biological ageing. Here, we systematically reviewed studies investigating systemic C-reactive protein in patients with age-related macular degeneration. We identified 53 studies with 60,598 participants (10,392 patients and 38,901 controls). Our meta-analyses revealed that early age-related macular degeneration was not associated to systemic C-reactive protein (Cohen's d = 0.03 [-0.04 to 0.10]; OR = 1.06 [0.93-1.20]; P = 0.39) whereas late age-related macular degeneration (Cohen's d = 0.38 [0.24 to 0.51]; OR = 1.99 [1.55-2.52]; P < 0.0001), and neovascular age-related macular degeneration (Cohen's d = 0.40 [0.24 to 0.56]; OR = 2.07 [1.55-2.76]; P < 0.0001) was associated with a small-to-moderate increase in systemic C-reactive protein. Our review provides an overview of this extensively studied field, provide summary estimates that provide insight into when and to what extent systemic C-reactive protein is associated with age-related macular degeneration, and help in distinguishing the potentially reversible disease processes from that of irreversible retinal ageing.

Risk factors for progression of age-related macular degeneration

Purpose

Age‐related macular degeneration (AMD) is a degenerative disease of the macula, often leading to progressive vision loss. The rate of disease progression can vary among individuals and has been associated with multiple risk factors. In this review, we provide an overview of the current literature investigating phenotypic, demographic, environmental, genetic, and molecular risk factors, and propose the most consistently identified risk factors for disease progression in AMD based on these studies. Finally, we describe the potential use of these risk factors for personalised healthcare.

Recent findings

While phenotypic risk factors such as drusen and pigment abnormalities become more important to predict disease progression during the course of the disease, demographic, environmental, genetic and molecular risk factors are more valuable at earlier disease stages. Demographic and environmental risk factors such as age and smoking are consistently reported to be related to disease progression, while other factors such as sex, body mass index (BMI) and education are less often associated. Of all known AMD variants, variants that are most consistently reported with disease progression are rs10922109 and rs570618 in CFH, rs116503776 in C2/CFB/SKIV2L, rs3750846 in ARMS2/HTRA1 and rs2230199 in C3. However, it seems likely that other AMD variants also contribute to disease progression but to a lesser extent. Rare variants have probably a large effect on disease progression in highly affected families. Furthermore, current prediction models do not include molecular risk factors, while these factors can be measured accurately in the blood. Possible promising molecular risk factors are High‐Density Lipoprotein Cholesterol (HDL‐C), Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), zeaxanthin and lutein.

Summary

Phenotypic, demographic, environmental, genetic and molecular risk factors can be combined in prediction models to predict disease progression, but the selection of the proper risk factors for personalised risk prediction will differ among individuals and is dependent on their current disease stage. Future prediction models should include a wider set of genetic variants to determine the genetic risk more accurately, and rare variants should be taken into account in highly affected families. In addition, adding molecular factors in prediction models may lead to preventive strategies and personalised advice.

Age-related macular degeneration among the elderly: The 5th National Health and Nutrition Examination Survey, 2010 through 2012

AIM

This study was conducted to identify the prevalence and factors associated with age-related macular degeneration (AMD) in Korean elderly.

METHODS

The study population of this cross-sectional survey was the Korean Health and Nutrition Examination Survey (KHANES) 2010 through 2012, the fifth population-based study.

RESULTS

Analysis of 2,767 elderly (above age 65) from 23,376 participants showed the prevalence of any AMD to be 17.6% in the Korean elderly. Factors that were significantly positively associated with AMD included age, sex, occupation, low socioeconomic status, liver cirrhosis and physical activity (p < .01). Significantly negatively associated with AMD were cardiovascular disease, obesity, and beta-carotene intake (p < .05).

CONCLUSIONS

This study estimated the prevalence rate and assessed factors associated with AMD in the elderly. This can be used to build a strategy for elderly eye health, and provides valuable information for screening for putative risks in the elderly.

Ophthalmologic evaluation of severely obese patients undergoing bariatric surgery: A pilot, monocentric, prospective, open-label study

Purpose

The aim of this study was to investigate the pathogenic role of obesity on blinding eye diseases in a population of severely obese patients with no history of eye diseases, and to verify whether weight loss induced by bariatric surgery may have a protective effect.

Methods

This was a pilot, monocentric, prospective, and open label study conducted at the University Hospital of Pisa. Fifty-seven severely obese patients with a mean body mass index value of 44.1 ± 6 kg/m² were consecutively recruited and received a complete ophthalmological evaluation and optical coherence tomography. Twenty-nine patients who underwent gastric bypass were evaluated also 3 months, and 1 year after surgery.

Results

At baseline, blood pressure value were directly and significantly related to intraocular pressure values (p<0.05, R = 0.35). Blood pressure values were also significantly and inversely related to retinal nerve fiber layer thickness, particularly in the temporal sector (RE p<0.05 r-0.30; LE p<0.01, R = -0.43). Moreover, minimum foveal thickness values were significantly and inversely associated with body mass index (RE p<0.02, R = -0.40; LE p<0.02, R = -0.30). A significant reduction of body mass index (p<0.05) and a significant (p<0.05) improvement of blood pressure was observed three months and one year after gastric bypass, which were significantly associated with an increase in retinal nerve fiber layer thickness and minimum foveal thickness values in both eyes (p<0.05).

Conclusions

The results of this study suggest that obese patients may have a greater susceptibility to develop glaucomatous optic nerve head damage and age-related macular degeneration. Moreover, weight reduction and improvement of comorbidities obtained by bariatric surgery may be effective in preventing eye disease development by improving retinal nerve fiber layer and foveal thickness.

Prevalence of age-related macular degeneration in an elderly UK Caucasian population-The Bridlington Eye Assessment Project: a cross-sectional study

ImportanceThere is paucity of data on prevalence and disease asymmetry of age-related macular degeneration (AMD), particularly the earlier stages, in the UK population.Objective and PurposeTo determine the prevalence of age-related macular degeneration in an elderly Caucasian UK population.DesignCross-sectional population study, 2002-2006.ParticipantsResidents in the study area of Bridlington aged 65 years and older.MethodsFull-ophthalmic examination was undertaken in 3549 participants, of eligible 6319 Caucasian population (response rate of 56%). Non-stereoscopic Colour fundus photographs (30°) were graded masked using a modified Rotterdam Classification for 3475 (98%) participants with gradable images. Prevalence for different AMD grades were calculated. Demographic details were analysed then integrated with the AMD gradings for full analysis. Prevalence rates for the different AMD Grades were calculated, as well as the age-specific prevalences.ResultsAMD prevalence in the worst eye were 38.5% grade 0, 41.4% grade 1, 12.8% grade 2, 2.8% grade 3, and 4.6% grade 4. Geographic atrophy (grade 4a) occurred in 2.5%, and neovascular AMD (grade 4b) in 1.8%. Prevalence increased with age such that grade 4 (advanced) AMD was 2.2% in the 65-69 years group, 15.8% for the 85-90, and 21.2% for over 90 years. There was significant asymmetry between the two eyes of individuals with advanced AMD (P<0.001), such that vision loss was unilateral. Persons with more advanced AMD grades were more likely to be dissatisfied with their vision.ConclusionsAdvanced AMD occurs more commonly in the UK Caucasian population than previously reported. Significant asymmetry between the two eyes occurs in individuals with unilateral advanced AMD so that visual impairment statistics do not represent true prevalence of advanced AMD. Persons with more advanced AMD were more likely to be dissatisfied with their vision.

The Association between the Lipids Levels in Blood and Risk of Age-Related Macular Degeneration

Lipid metabolism may be involved in the pathogenic mechanism of age-related macular degeneration (AMD). However, conflicting results have been reported in the associations of AMD with blood lipids. We performed a meta-analysis including a total of 19 studies to evaluate associations between blood lipids and this disease. The result reported that the high level of high-density lipoprotein cholesterol (HDL-C) obtained with an increment of 1 mmol/L could result in a significantly increase in the AMD risk of approximately 18% (relative risk (RR), 1.18; 95% confidence interval (CI), 1.01 to 1.35; I² = 53.8%; p = 0.007). High levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were significantly associated with a decreased risk of AMD (RRs ranging from 0.92 to 0.95; all p < 0.05). The stratified analysis based on AMD subtypes showed that these blood lipids were only significantly associated with the risk of early AMD (all p < 0.05). The association between the blood lipids and AMD risk did not differ substantially based on the other characteristics of the participants. A high HDL-C level was associated with an increased AMD risk, whereas participants with high TC, LDL-C, and TG concentrations may show a decreased risk for this disease. Further well-designed large studies are warranted to confirm the conclusions.

Experiences with developing and implementing a virtual clinic for glaucoma care in an NHS setting

Background

This article describes the development of a virtual glaucoma clinic, whereby technicians collect information for remote review by a consultant specialist.

Design and Methods

This was a hospital-based service evaluation study. Patients suitable for the stable monitoring service (SMS) were low-risk patients with “suspect”, “early”-to-“moderate” glaucoma who were deemed stable by their consultant care team. Three technicians and one health care assistant ran the service. Patients underwent tests in a streamlined manner in a dedicated clinical facility, with virtual review of data by a consultant specialist through an electronic patient record.

Main outcome measure

Feasibility of developing a novel service within a UK National Health Service setting and improvement of patient journey time within the service were studied.

Results

Challenges to implementation of virtual clinic include staffing issues and use of information technology. Patient journey time within the SMS averaged 51 minutes, compared with 92 minutes in the glaucoma outpatient department. Patient satisfaction with the new service was high.

Conclusion

Implementing innovation into existing services of the National Health Service is challenging. However, the virtual clinic showed an improved patient journey time compared with that experienced within the general glaucoma outpatient department. There exists a discrepancy between patient management decisions of reviewers, suggesting that some may be more risk averse than others when managing patients seen within this model. Future work will assess the ability to detect progression of disease in this model compared with the general outpatient model of care.

Bevacizumab versus Ranibizumab on As-Needed Treatment Regimen for Neovascular Age-Related Macular Degeneration in Turkish Patients

Purpose. To compare the efficacy of intravitreal bevacizumab versus ranibizumab in the treatment of neovascular age-related macular degeneration (nAMD). Methods. Retrospective, comparative study. The newly diagnosed nAMD patients who were treated with intravitreal bevacizumab or ranibizumab on an as-needed treatment regimen were included in the study. Main outcome measures were the change in best corrected visual acuity (BCVA), and central retinal thickness (CRT). Secondary outcome measures were the number of injections, and complications. Results. A total of 154 patients were included in the study. Bevacizumab group consisted of 79 patients, and ranibizumab group consisted of 74 patients. Mean follow-up time was 18.9 months, and 18.3 months in the bevacizumab and ranibizumab groups, respectively. There was not a significant difference between the two groups regarding the change in BCVA and CRT at all time points (P > 0.05 for all). The mean number of injections at month 12 was 4.8 and 4.7 in bevacizumab and ranibizumab groups, respectively (P > 0.05). No serious complications were detected in any of the groups. Conclusion. Both of the bevacizumab and ranibizumab found to be effective in the treatment of nAMD in regards of functional and anatomical outcomes with similar number of treatments and similar side effects.

The effect of CFH polymorphisms on the response to the treatment of age-related macular degeneration (AMD) with intravitreal ranibizumab

PURPOSE

The purpose of this study is to evaluate the effect of complement factor H (CFH) Y402H CC and TT polymorphisms on treatment response to intravitreal ranibizumab injection in patients with wet age-related macular degeneration (AMD).

METHODS

One hundred ninety-three patients with choroidal neovascularization (CNV) secondary to AMD who were monitored for at least 6 months of follow-up, and with at least three ranibizumab injections, were included in the study. At the final examination, an increase in visual acuity (VA) of five letters or more compared to the initial VA was regarded as a good response, and a decrease in VA of five letters or more compared to the initial VA was evaluated as a poor response. A genetic examination was performed with a PCR melting curve analysis. In the statistical evaluation, SPSS version 18 software was used.

RESULTS

The mean age of the patients was 71.01 (55-86) years, the mean follow-up was 13.34 (6-36) months, and the mean number of injections was 4.02 (3-15). There were 96 patients in the good response group (Group 1) and 97 patients in the poor response group (Group 2). The initial VA in Group 1 was 41.34 (10-64) letters, the initial central macular thickness (CMT) was 213.40 (126-494) µm, and the initial lesion width was 3760 (1430-6430) µm. The initial VA in Group 2 was 52.89 (26-82) letters, the initial CMT was 257.60 (115-882) µm, and the initial lesion width was 4460 (1000-7650) µm. There was no statistically significant difference between the two groups in terms of the initial VA and CMT (p=0.094, p=0.083). However, there was a statistically significant difference between the groups in the width of the initial lesion (p=0.003). In Group 1, 15 CC, 30 TT, and 51 TC alleles were found, and in Group 2, 49 CC, two TT, and 46 TC alleles were found, and the distribution was significantly different between the two groups (p=0.012). The change in the distribution of genotypes was not associated with either the lesion size or VA (p=0.841). Fibrosis developed in 12 patients who were all poor responders.

CONCLUSIONS

CFH Y402H CC accompanied a poor response, and TT accompanied a good response in this series of patients with AMD undergoing ranibizumab therapy.

Is spectral-domain optical coherence tomography essential for flexible treatment regimens with ranibizumab for neovascular age-related macular degeneration?

Purpose. To evaluate the ability of spectral-domain optical coherence tomography to detect subtle amounts of retinal fluid when the choroidal neovascularization is detected as inactive via time-domain optical coherence tomography and clinical examination in neovascular age-related macular degeneration (nAMD) patients. Methods. Forty-nine eyes of 49 patients with nAMD after ranibizumab treatment were included in this cross-sectional, prospective study. All patients were imaged with TD-OCT and SD-OCT at the same visit one month after a ranibizumab injection. The presence of subretinal, intraretinal, and subretinal pigment epithelium fluid (subRPE) in SD-OCT was evaluated; also mean central retinal thickness (CRT) and the rate of vitreoretinal surface disorders detected via the two devices were evaluated. Results. The mean CRT via TD-OCT and SD-OCT was 218.1 ± 51.3 and 325.7 ± 78.8 microns. Sixteen patients (32.6%) showed any kind of retinal fluid via SD-OCT. In detail, 8 patients (16.3%) showed subretinal fluid, 10 patients (20.4%) showed intraretinal fluid, and 3 patients (6.1%) showed SubRPE fluid. The ability of detecting vitreoretinal surface disorders was comparable between the two devices, except vitreomacular traction. Conclusion. SD-OCT is essential for the nAMD patients who are on an as-needed treatment regimen with ranibizumab. Only TD-OCT and clinical examination may cause insufficient treatment in this group of patients.

Genetic risk factors and age-related macular degeneration (AMD)

Age related macular degeneration (AMD) is the leading cause of blindness in individuals older than 65 years of age. It is a multifactorial disorder and identification of risk factors enables individuals to make lifestyle choices that may reduce the risk of disease. Collaboration between geneticists, ophthalmologists, and optometrists suggests that genetic risk factors play a more significant role in AMD than previously thought. The most important genes are associated with immune system modulation and the complement system, e.g., complement factor H (CFH), factor B (CFB), factor C3, and serpin peptidase inhibitor (SERPING1). Genes associated with membrane transport, e.g., ATP-binding cassette protein (ABCR) and voltage-dependent calcium channel gamma 3 (CACNG3), the vascular system, e.g., fibroblast growth factor 2 (FGF2), fibulin-5, lysyl oxidase-like gene (LOXL1) and selectin-P (SELP), and with lipid metabolism, e.g., apolipoprotein E (APOE) and hepatic lipase (LIPC) have also been implicated. In addition, several other genes exhibit some statistical association with AMD, e.g., age-related maculopathy susceptibility protein 2 (ARMS2) and DNA excision repair protein gene (ERCC6) but more research is needed to establish their significance. Modifiable risk factors for AMD should be discussed with patients whose lifestyle and/or family history place them in an increased risk category. Furthermore, calculation of AMD risk using current models should be recommended as a tool for patient education. It is likely that AMD management in future will be increasingly influenced by assessment of genetic risk as such screening methods become more widely available.

The eye as a model of ageing in translational research--molecular, epigenetic and clinical aspects

The eye and visual system are valuable in many areas of translational research such as stem cell therapy, transplantation research and gene therapy. Changes in many ocular tissues can be measured directly, easily and objectively in vivo (e.g. lens transparency; retinal blood vessel calibre; corneal endothelial cell counts) and so the eye may also be a uniquely useful site as a model of ageing. This review details cellular, molecular and epigenetic mechanisms related to ageing within the eye, and describes ocular parameters that can be directly measured clinically and which might be of value in ageing research as the translational "window to the rest of the body". The eye is likely to provide a valuable model for validating biomarkers of ageing at molecular, epigenetic, cellular and clinical levels. A research agenda to definitively establish the relationship between biomarkers of ageing and ocular parameters is proposed.