Case-control study of the risk factors for age related macular degeneration. France-DMLA Study Group

The Need for Artificial Intelligence Based Risk Factor Analysis for Age-Related Macular Degeneration: A Review

In epidemiology, a risk factor is a variable associated with increased disease risk. Understanding the role of risk factors is significant for developing a strategy to improve global health. There is strong evidence that risk factors like smoking, alcohol consumption, previous cataract surgery, age, high-density lipoprotein (HDL) cholesterol, BMI, female gender, and focal hyper-pigmentation are independently associated with age-related macular degeneration (AMD). Currently, in the literature, statistical techniques like logistic regression, multivariable logistic regression, etc., are being used to identify AMD risk factors by employing numerical/categorical data. However, artificial intelligence (AI) techniques have not been used so far in the literature for identifying risk factors for AMD. On the other hand, artificial intelligence (AI) based tools can anticipate when a person is at risk of developing chronic diseases like cancer, dementia, asthma, etc., in providing personalized care. AI-based techniques can employ numerical/categorical and/or image data thus resulting in multimodal data analysis, which provides the need for AI-based tools to be used for risk factor analysis in ophthalmology. This review summarizes the statistical techniques used to identify various risk factors and the higher benefits that AI techniques provide for AMD-related disease prediction. Additional studies are required to review different techniques for risk factor identification for other ophthalmic diseases like glaucoma, diabetic macular edema, retinopathy of prematurity, cataract, and diabetic retinopathy.

Altered Blood Flow in the Ophthalmic and Internal Carotid Arteries in Patients with Age-Related Macular Degeneration Measured Using Noncontrast MR Angiography at 7T

BACKGROUND AND PURPOSE

Age-related macular degeneration is associated with reduced perfusion of the eye; however, the role of altered blood flow in the upstream ophthalmic or internal carotid arteries is unclear. We used ultra-high-field MR imaging to investigate whether the diameter of and blood flow in the ophthalmic artery and/or the ICA are altered in age-related macular degeneration and whether any blood flow changes are associated with disease progression.

MATERIALS AND METHODS

Twenty-four patients with age-related macular degeneration and 13 similarly-aged healthy controls participated. TOF and high-resolution dynamic 2D phase-contrast MRA (0.26 × 0.26 × 2mm³, 100-ms effective sampling rate) was acquired at 7T. Vessel diameters were calculated from cross-sectional areas in phase-contrast acquisitions. Blood flow time-series were measured across the cardiac cycle.

RESULTS

The ophthalmic artery vessel diameter was found to be significantly smaller in patients with age-related macular degeneration than in controls. Volumetric flow through the ophthalmic artery was significantly lower in patients with late age-related macular degeneration, with a significant trend of decreasing volumetric ophthalmic artery flow rates with increasing disease severity. The resistance index was significantly greater in patients with age-related macular degeneration than in controls in the ophthalmic artery. Flow velocity through the ophthalmic artery and ICA was significantly higher in patients with age-related macular degeneration. Ophthalmic artery blood flow as a percentage of ipsilateral ICA blood flow was nearly double in controls than in patients with age-related macular degeneration.

CONCLUSIONS

These findings support the hypothesis that vascular changes upstream to the eye are associated with the severity of age-related macular degeneration. Additional investigation into the potential causality of this relationship and whether treatments that improve ocular circulation slow disease progression is warranted.

Does Cataract Surgery Improve the Progression of Age-Related Macular Degeneration? A Meta-Analysis

Purpose

Cataract and age-related macular degeneration (AMD) are the common causes of blindness in the elderly. Although cataract surgery is the most effective treatment for cataract, some clinicians suspect that such interventions may accelerate the progression of AMD. Therefore, we carried out this meta-analysis to focus on demonstrating the effectiveness and safety of cataract surgery in eyes with AMD.

Methods

We performed a systematic literature search in the PubMed, EMBASE, and Cochrane Library databases, and the electronic databases were last searched in January 2019. We planned to include cohort trials of eyes affected by both cataract and AMD in which cataract surgery would be compared to no surgery. Two reviewers independently evaluated the search results against the inclusion and exclusion criteria. 8 trials were included for this meta-analysis.

Results

We used the Stata/12.0 to integrate the data that was extracted from the articles. Eight cohort trials with data from different study populations were included. In random effects model, the relative risk (RR) for the progression of AMD is 1.194 (95% CI 0.897–1.591). As for those grouped according to the follow-up year, the RR for longer than five years was 1.372 (95% CI 1.062–1.772).

Conclusion

We could draw out such a conclusion that there is still a positive correlation between cataract surgery and the progression of AMD, especially for the Asians. However, based on the current results, it is not possible to draw conclusions from existing studies on the impact of cataract surgery on early AMD development.

Ocular Axial Length and Diabetic Retinopathy: The Kailuan Eye Study

Purpose

To examine the role of ocular axial length as an ocular parameter for the prevalence and severity of diabetic retinopathy (DR).

Methods

The cross-sectional Kailuan Diabetic Retinopathy Study included patients with diabetes who participated in the community-based longitudinal Kailuan Study and who had undergone ocular fundus photography. The fundus photographs were graded using the Early Treatment of Diabetic Retinopathy Study criteria.

Results

The study included 1096 patients with diabetes (mean age: 60.8 ± 9.4 years; axial length: 23.37 ± 0.92 mm). In binary regression analysis, a higher DR prevalence was associated with shorter axial length (P = 0.007; odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.70, 0.95) after adjusting for longer known duration of diabetes (P = 0.02; OR: 1.13; 95%CI: 1.02, 1.24) and higher fasting blood glucose concentration (P < 0.001; OR: 1.38; 95%CI: 1.26, 1.52). A more severe DR stage was associated (regression coefficient r: 0.46) with shorter ocular axial length (P = 0.047; standardized regression coefficient β: -0.06) after adjusting for higher fasting blood glucose (P < 0.001; β: 0.41) and longer known duration of diabetes (P = 0.045; β: 0.07). Longer axial length was associated with a lower DR prevalence (P = 0.003; β: -0.10) after adjusting for younger age (P < 0.001), male sex (P < 0.001), higher body mass index (P = 0.016), and lower fasting blood glucose concentration (P = 0.036).

Conclusions

After adjusting for systemic risk factors, DR prevalence decreased by 19% (95%CI: 5, 30) for each millimeter increase in axial length. With longer axial length being a surrogate for axial myopia, the marked increase in myopia prevalence worldwide may lead to a relative decrease in the prevalence and incidence of DR in future.

Axial length and its associations in a Russian population: The Ural Eye and Medical Study

Purpose

To assess the normal distribution of axial length and its associations in a population of Russia.

Methods

The population-based Ural Eye and Medical Study included 5,899 (80.5%) individuals out of 7328 eligible individuals aged 40+ years. The participants underwent an ocular and systemic examination. Axial length was measured sonographically (Ultra-compact A/B/P ultrasound system, Quantel Medical, Cournon d'Auvergne, France).

Results

Biometric data were available for 5707 (96.7%) individuals with a mean age of 58.8±10.6 years (range:40–94 years; 25%, 50%, 75% quartile: 51.0, 58.0, 66.0 years, respectively). Mean axial length was 23.30±1.10 mm (range: 19.02–32.87mm; 95% confidence interval (CI): 21.36–25.89; 25%, 50%, 75% quartile: 22.65mm, 23.23mm, 23.88mm, resp.). Prevalences of moderate myopia (axial length:24.5-<26.5mm) and high myopia (axial length >26.5mm) were 555/5707 (8.7%;95%CI:9.0,10.5) and 78/5707 (1.4%;95%CI:1.1,1.7), respectively. Longer axial length (mean:23.30±1.10mm) was associated (correlation coefficient r²:0.70) with older age (P<0.001;standardized regression coefficient beta:0.14), taller body height (P<0.001;beta:0.07), higher level of education (P<0.001;beta:0.04), higher intraocular pressure (P<0.001;beta:0.03), more myopic spherical refractive error (P<0.001;beta:-0.55), lower corneal refractive power (P<0.001;beta:-0.44), deeper anterior chamber depth (P<0.001;beta:0.20), wider anterior chamber angle (P<0.001;beta:0.05), thinner peripapillary retinal nerve fiber layer thickness (P<0.001;beta:-0.04), higher degree of macular fundus tessellation (P<0.001;beta:0.08), lower prevalence of epiretinal membranes (P = 0.01;beta-0.02) and pseudoexfoliation (P = 0.007;beta:-0.02) and higher prevalence of myopic maculopathy (P<0.001;beta:0.08). In that model, prevalence of age-related macular degeneration (any type: P = 0.84; early type: P = 0.46), diabetic retinopathy (P = 0.16), and region of habitation (P = 0.27) were not significantly associated with axial length.

Conclusions

Mean axial length in this typically multi-ethnic Russian study population was comparable with values from populations in Singapore and Beijing. In contrast to previous studies, axial length was not significantly related with the prevalences of age-related macular degeneration and diabetic retinopathy or region of habitation.

Iris Color and Lens Thickness in Chinese Teenagers

Purpose

We aimed to determine the association of iris color with lens thickness (LT) in a school-based sample of Chinese teenagers.

Methods

In total, 2346 grade 7 students, from 10 middle schools, aged 13 to 14 years in Mojiang located in Southwestern China were included in the analysis. A grading system was developed to assess iris color based on standardized slit-lamp photographs. LT was measured by the LenStar LS900. Refractive error was measured after cycloplegia using an autorefractor and ocular biometric parameters, including axial length (AL), were measured using an IOL Master.

Results

There was a significant trend of decreasing LTs with darker iris color. On average, eyes with “grade 1” (the lightest) iris color, when compared with those with “grade 5” (the darkest), had greater LTs (mean difference, 0.1 mm). After adjusting for other potential confounders including sex, height, and ALs in generalized estimating equation models, the trend was similar and did not change significantly. Compared with individuals with iris color of grade 1, those with grade 5 had a thinner lens of 0.1 mm (95% confidence interval [CI]: 0.01, 0.19) in sex-adjusted model and a 0.09 mm (95% CI: 0, 0.18) in multivariate-adjusted model.

Conclusions

Lighter iris color might be associated with greater LTs in Chinese teenagers. The biological mechanisms underlying the association warrant further clarification.

Translational Relevance

As LT is an important refractive component, knowledge on the effect of iris color on LTs may assist in the design of novel technologies, which could control refractive development.

Gout and the risk of age-related macular degeneration in the elderly

Objective

To assess whether gout is associated with incident age-related macular degeneration (AMD)

Methods

We used the 5% Medicare claims data from 2006–12 for all beneficiaries who were enrolled in Medicare fee-for-service (Parts A, B) and not enrolled in a Medicare Advantage Plan, and resided in the U.S. People were censored at the occurrence of new diagnosis of AMD, death or the end of study (12/31/2012), whichever occurred first. We used multivariable-adjusted Cox regression analyses to assess the association of gout with incident AMD, adjusted for demographics, comorbidity, and use of medications for cardiovascular disease and gout. Hazard ratios and 95% confidence intervals were calculated.

Results

In this observational cohort study, of the 1,684,314 eligible people, 116,097 developed incident AMD (6.9%). Incidence rates of AMD per 1,000 person-years were 20.1 for people with gout and 11.7 for people without gout. In multivariable-adjusted analyses, a diagnosis of gout was significantly associated with a higher risk of incident AMD with a hazard ratio of 1.39 (95% CI, 1.35, 1.43). This association was confirmed in sensitivity analyses that substituted Charlson-Romano comorbidity index continuous score with either a categorical Charlson-Romano comorbidity index score or individual Charlson-Romano index comorbidities plus hypertension, hyperlipidemia and coronary artery disease. Other covariates significantly associated with higher hazards of incident AMD were older age, female gender, White race/ethnicity, and higher Charlson-Romano comorbidity index score.

Conclusions

We noted a novel association of gout with AMD in the elderly. Future studies should investigate the pathways that mediate this association.

Early Age-Related Maculopathy and Risk Factors of Cardiovascular Disease in Middle-Aged Lithuanian Urban Population

Purpose

To assess the prevalence of age-related maculopathy (ARM) in a middle-aged urban population and the relationship between ARM and the main risk factors of cardiovascular disease (CVD).

Methods

The survey according to the WHO MONICA study protocol was carried out in Kaunas city, Lithuania, from 2001 to 2002. A total of 1403 persons aged 35 to 64 years were screened (626 men and 777 women: response rate 62.4%). Ophthalmologic investigation was performed for 1337 respondents (594 men and 743 women). Analysis of the relationship between ARM and risk factors of CVD was performed in case-control subdivision matching for sex, age, and education level.

Results

Early ARM was diagnosed in 7.4% of men and 5.4% of women. Rate of current smoking in case and control groups did not differ in men but in case group of women it was greater than in control group. Mean systolic and diastolic blood pressure and body mass index (BMI) in male case group and mean fasting blood glucose concentration in female case group were higher than in corresponding control groups. Frequency of diastolic hypertension (diastolic blood pressure ≥90 mmHg) and obesity (BMI ≥30 kg/m2) in male case group was higher than in control group. ARM was not associated with cholesterol and triglyceride levels in men and women.

Conclusions

Early ARM in middle-aged Lithuanian urban population was associated with current smoking in women but not in men; it was associated with diastolic blood pressure and BMI in men and with fasting glucose level in women.

Neovascular age-related macular degeneration is not associated with coronary heart disease in a Chinese Population: a population-based study

PURPOSE

This case-control study aimed to explore the association between prior coronary heart disease (CHD) and neovascular age-related macular degeneration (AMD) using a population-based data set in Taiwan.

METHODS

We analysed data sourced from the Taiwan Longitudinal Health Insurance Database 2005. The study consisted of 1970 patients with neovascular AMD as cases and 5910 age- and sex-matched controls. We performed a conditional logistic regression to examine the odds ratio (OR) and its corresponding 95% confidence interval (CI) for previously diagnosed CHD between cases and controls.

RESULTS

Of the 7880 sampled patients, 24.5% had a prior history of CHD; CHD was found in 25.7% of cases and in 22.7% of controls (p = 0.008). The conditional logistic regression analysis indicated that the OR for prior CHD for cases was 1.17 [95% confidence interval (CI): 1.04-1.32] compared to the controls. However, after adjusting for patient's monthly income, geographic location, urbanization level, age, hyperlipidaemia, diabetes and hypertension, we failed to observe an association between prior CHD and AMD (OR = 1.03, 95% CI = 0.91-1.17). Additionally, the medical comorbidities of hyperlipidaemia (adjusted OR = 1.29, 95% CI = 1.15-1.45), hypertension (adjusted OR = 1.20, 95% CI = 1.05-1.37) and diabetes (adjusted OR = 1.47, 95% CI = 1.32-1.65) were significantly associated with AMD.

CONCLUSIONS

This study presented no significant difference in the odds of prior CHD between patients with AMD and those without AMD after adjusting for comorbidities and sociodemographic characteristics in a Chinese population.

Prevalence of and risk factors for age-related macular degeneration in Nepal: the Bhaktapur Retina Study

Aim

This study aimed to explore the prevalence of and risk factors for age-related macular degeneration (AMD) in an elderly population in Nepal.

Subjects and methods

This is a population-based, cross-sectional study. A sample size of 2,100 was calculated. A total of 1,860 (88.6%) subjects aged >60 years were enrolled for the study from 30 clusters in the district. Detailed history, visual acuity, and anterior segment and posterior segment examinations were performed. AMD was graded according to the International ARM Epidemiological Study Group.

Results

Among the total study population, 659 subjects had any AMD (35.43%; 95% confidence interval [CI]: 33.25–37.65), 484 had mild dry AMD (26.02%; 95% CI: 24.04–28.08), 143 had intermediate dry AMD (7.69%; 95% CI: 6.52–8.99), 19 had geographic atrophy (1.02%; 95% CI: 0.61–1.59), and 13 had wet AMD (0.70%; 95% CI: 0.37–1.19). The overall prevalence of early and late AMD was 33.71% and 1.72%, respectively. Among subjects with dry and wet AMD, 36.53% and 46.1% had visual impairment, while 2.78% and 23.08% were blind, respectively. In multivariate analysis, AMD was significantly higher in subjects with an increased number of cigarettes smoked per day (odds ratio [OR] 1.02, 95% CI: 1.01–1.04; P=0.007) and in subjects with pseudophakia (OR 1.45, 95% CI: 1.12–1.87; P=0.005).

Conclusion

One-third of the population aged ≥60 years have some form of AMD. There was a significant association with the number of cigarettes consumed and with previous cataract surgery.

Sensitivity and Specificity of Preschool Vision Screening in Iran

BACKGROUND

To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the National Vision Screening Program for 7 yr old children in Iran.

METHODS

In this cross-sectional study, eight cities in Iran were selected through multistage cluster sampling. Selected cities were Sari, Birjand, Ardabil, Mashhad, Bandar Abbas, Dezful, Yazd, and Arak, in Iran in 2013. Totally, 4614 schoolchildren were selected, 4106 of which participated in the study. An optometrist at the school site conducted all vision tests. Results were compared against those recorded on each child's health card. Those with an uncorrected visual acuity worse than 20/25 in at least one eye screened positive for a vision problem.

RESULTS

8.49% [95% confidence interval, 7.65 to 9.39] of the examinees had a vision problem. The sensitivity rate of the school entry screening was 38.15% (95% CI, 33.01 to 43.50) and the specificity rate was 93.11 (95%CI 92.25 to 93.90). The positive and negative predictive values were 33.93 (29.24 to 38.88) and 94.19 (93.39 to 94.93), respectively. Sensitivity and specificity rates did not significantly differ between boys and girls. For the uncorrected visual acuity tested by public health care workers compared to optometrists, the area under the ROC surface was 0.741 (P<0.001). The best-associated criterion was an uncorrected visual acuity more than 0.05 LogMAR with 67.3% sensitivity and 74.7% specificity.

CONCLUSION

The validity of the school entry vision screening by health workers is low. To reduce false negative rates, some supplementary examinations such as refraction and near visual acuity measurements as well as further training of screeners should be considered.

Age-Related Macular Degeneration and Coronary Artery Disease in a VA Population

OBJECTIVES

Age-related macular degeneration (AMD) is the leading cause of blindness in the United States. Although AMD shares multiple risk factors with coronary artery disease (CAD), the association between AMD and CAD has not been established. The objective of our study was to demonstrate an association between the diagnosis of AMD and CAD and/or major cardiovascular risk factors.

METHODS

We performed a retrospective chart review of >13,000 patients at the Lexington Veterans Affairs Medical Center. Patients diagnosed as having AMD served as cases, and patients diagnosed with cataract and no AMD served as controls. We examined the prevalence of CAD and associated risk factors in both groups using univariate analysis followed by multivariate analyses to examine the association between AMD and CAD after adjusting for known common risk factors.

RESULTS

We identified 3950 patients with AMD and 9166 controls. Patients with AMD were on average 6 years older than controls (P < 0.001) and had a significantly higher prevalence of CAD (39% vs 34%) and hypertension (88% vs 83%) but lower incidence of diabetes mellitus and smoking. Estimated odds ratio relating CAD to AMD was 1.22 (95% confidence interval 1.13-1.32; P < 0.001). The association between CAD and AMD remained significant in multivariate analyses in older individuals (76 years and older). When we conducted a secondary analysis and matched the AMD and non-AMD groups based on age, the association between CAD and AMD remained significant (39.4% in the AMD group vs 36.6% in the non-AMD group; P = 0.011).

CONCLUSIONS

These findings support the existence of an association between CAD and AMD, particularly in older adult patients in the predominantly male Veterans Affairs population. Such an association between AMD and systemic vascular disease justifies the potential coscreening for these conditions.

Cataract surgery and age-related macular degeneration. An evidence-based update

Purpose

Age‐related macular degeneration (AMD) and cataract often coexist in patients and concerns that cataract surgery is associated with an increased risk of incidence or progression of existing AMD has been raised. This systematic review and meta‐analysis is focused on presenting the evidence concerning progression of AMD in patients undergoing cataract surgery.

Methods

We performed a systematic literature search in the PubMed, Medline, Cochrane Library and CINAHL databases. Two randomized trials and two case–control trials were identified. Quality of the studies was assessed using the Cochrane risk of bias tool, data were extracted, and meta‐analyses were performed. Quality of the available evidence was evaluated using the GRADE system.

Results

We found that visual acuity at 6–12 months follow‐up was significantly better (6.5–7.5 letters) in eyes that had undergone cataract surgery than in unoperated eyes, but the included number of subjects was small, and hence, the quality of evidence was downgraded to moderate. We did not find an increased risk of progression to exudative AMD 6–12 months after cataract surgery [RR 3.21 (0.14–75.68)], but the included number of subjects was small, and thus, the quality of the evidence was moderate.

Conclusion

Cataract surgery increases visual acuity without an increased risk of progression to exudative AMD, but further research with longer follow‐up is encouraged.

The Royal College of Ophthalmologists' National Ophthalmology Database Study of cataract surgery: report 2, relationships of axial length with ocular copathology, preoperative visual acuity, and posterior capsule rupture

PURPOSE

To describe the relationships of axial length with ocular copathology, preoperative visual acuity, and posterior capsule rupture rates in patients undergoing cataract surgery.DesignThe Royal College of Ophthalmologists' National Ophthalmology Database (NOD) study.

METHODS

Anonymised data on 180 114 eyes from 127 685 patients undergoing cataract surgery between August 2006 and November 2010 were collected prospectively from 28 sites. Data parameters included: demographics, biometry, ocular copathology, visual acuity measurements, and surgical complications including posterior capsule rupture, or vitreous loss or both (PCR).

RESULTS

Consultant surgeons performed a higher proportion of operations on eyes whose axial length were at the extremes. Glaucoma and age related macular degeneration were more common in eyes with shorter axial lengths, whilst previous vitrectomy was associated with longer axial lengths. Eyes with brunescent or white cataracts or amblyopia were more common at both axial length extremes. Preoperative visual acuities were similar for eyes with axial length measurements up to approximately 28 mm and worse for eyes with longer axial length measurements. PCR rates showed little change with axial length (overall mean 1.95%, 95% CI: 1.89 to 2.01%), except for a borderline increase in eyes with axial length <20.0 mm where rates were 3.6% (95% CI: 2.0 to 6.3%). The likelihood of PCR in eyes with axial length <20.0 mm was 1.88 times higher than those of ≥20.0 mm (P=0.0373).

CONCLUSION

Rates of ocular comorbidities vary by axial length. PCR rates in eyes with very short or long axial lengths were lower than expected.

Intravitreal vascular endothelial growth factor concentration and axial length

BACKGROUND

To examine the intravitreal concentration of vascular endothelial growth factor (VEGF) in dependence of the axial length in eyes without intraocular neovascularization.

METHODS

The concentrations of VEGF in vitreous samples and blood samples of patients undergoing pars plana vitrectomy for treatment of idiopathic macular holes or epiretinal membranes were examined using enzyme-linked immunosorbent assay. Axial length was determined by biometry.

RESULTS

The study included 34 patients with macular holes (n = 21) or epiretinal membranes (n = 13) with a mean age of 62.4 ± 10.5 years (range: 35-76 years) and a mean axial length of 24.1 ± 1.8 mm (range: 21.0-29.1 mm). The intravitreal VEGF concentration (mean: 71.0 ± 63.2 pg/mL) was significantly (P < 0.001) lower than the VEGF concentration in the blood (830 ± 585 pg/mL). Both parameters were significantly associated with each other (P = 0.04; correlation coefficient r = 0.35). The intravitreal VEGF concentration was not significantly associated with gender (P = 0.25) or age (P = 0.48). A higher intravitreal VEGF concentration was significantly associated with a shorter axial length (P = 0.025; r = -0.39) or a higher hyperopic refractive error (P = 0.04; r = 0.35). Neither plasma concentration of VEGF nor the ratio of plasma VEGF concentrations to intravitreal VEGF concentration was significantly associated with axial length (P = 0.89 and P = 0.22, respectively) or with refractive error (P = 0.89 and P = 0.26, respectively).

CONCLUSION

Intravitreal VEGF concentration decreased with increasing axial length. It suggests a diluting effect in eyes with larger intraocular volume and/or a faster turnover rate of VEGF in axially myopic eyes with vitreous liquefaction.

The impact of cataract surgery on AMD development and progression

Age-related macular degeneration (AMD) and cataract are two leading causes of visual impairment worldwide which often occur concurrently in the same patient. With more than 1.6 million cataract operations performed per year in the United States, many of which occur in the nearly 1.75 million individuals diagnosed with AMD, there is ample incentive to further explore the interaction between these two conditions. Notably, the role of cataract surgery on AMD development and progression is of particular interest. This review summarizes the major findings from literature focusing on the effect of cataract surgery on AMD.

Intracameral interleukin 1β, 6, 8, 10, 12p, tumor necrosis factor α and vascular endothelial growth factor and axial length in patients with cataract

Objective

To assess associations between the aqueous humour concentration of interleukin IL-1β, IL-6, IL-8, IL-10 and IL-12p, tumor necrosis factor α (TNF-α) and vascular endothelial growth factor (VEGF) and axial length in eyes with cataract.

Methods

The hospital-based investigation included patients who underwent cataract surgery between March 2014 and April 2014. Using aqueous humour collected at the start of cataract surgery, the interleukins IL-1β, IL-6, IL-8, IL-10 and IL-12p, TNF-α and VEGF were examined using a cytometric bead array. Axial length was determined by partial coherence laser interferometry (IOL Master).

Results

The study included 33 patients with cataract (33 eyes) with a mean age of 69.2±10.8 years (range:50–87 years) and a mean axial length of 24.7±1.9 mm (range:22.6–31.5 mm). Lower aqueous concentration of VEGF was significantly associated with longer axial length (VEGF concentration (pg/mL) = -5.12 x Axial Length (mm) + 163; correlation coefficient r = -0.41; P<0.001) and more myopic refractive error (VEGF concentration (pg/mL) = 1.27xspherical equivalent (diopters)+44.8; r = 0.383; P = 0.002). The aqueous concentrations of all other substances were not significantly (all P>0.10) associated with axial length or refractive error.

Conclusions

Higher intravitreal concentrations of VEGF were measured in eyes with a longer axial length, while the intraocular concentrations of IL-1β, IL-6, IL-8, IL-10, IL-12p and TNF-α were not correlated with axial length. The lower concentration of VEGF in axially elongated eyes may be one of the reasons for the lower prevalence of age-related macular degeneration and diabetic retinopathy in myopic eyes.

Iris color and associated pathological ocular complications: a review of epidemiologic studies

AIM

To elucidate the associations of iris color with major eye diseases.

METHODS

A systematic search on Medline with coverage up to August 2013 was conducted. Assessment of the quality of studies based on their levels of evidence was in accordance with the Centre for Evidence-Based Medicine, Oxford, United Kingdom.

RESULTS

A relationship between darker iris color and an increased risk of age-related cataract has been reported from cross-sectional studies and prospective cohort studies. There was no consistent evidence supporting a major role of iris color in the development or progression of age-related macular degeneration. The association of iris color with ocular uveal melanoma has been confirmed by a meta-analysis of observational studies previously. The etiologic synergism between light iris color and environmental exposure such as UV the exposure of UV radiation was found. There were no studies evaluating the refractive associations with iris color but there may be a possible link between iris color and myopia.

CONCLUSION

Darker iris color is associated with an increased risk of cataract and a reduced risk of ocular uveal melanoma. The association of iris color with age-related macular degeneration is not confirmed. Ophthalmologists should be aware that the risk of ocular disorders appears to vary by differences in iris color.

[Review and expert opinion in age related macular degeneration. Focus on the pathophysiology, angiogenesis and pharmacological and clinical data]

Age related macular degeneration (AMD) is a pathological aging of the macula, brought about by the interaction of genetic and environmental factors. It induces geographic atrophy of the retina and/or choroidal neovascularization. In the latter, abnormal vessels develop from the choriocapillaris, with the involvement of VEGF (vascular endothelial growth factor). The VEGF family includes several factors, including VEGF-A, B, C, D, F and PlGF (placental growth factor). Their biological properties and their affinities to the VEGFR1, VEGFR2 and VEGFR3 receptors found on endothelial cells differ. Exudative AMD involves mainly VEGF-A and VEGF-R2. Anti-VEGF agents used in ophthalmology (ranibizumab, bevacizumab and aflibercept) are designed to primarily target this pathway. In vitro, all have sufficient affinity to their ligands. Their therapeutic efficacy must therefore be judged based on clinical criteria. In clinical practice, the minimum number of injections required for a satisfactory result appears to be comparable with all the three. The few available studies on therapeutic substitutions of anti-VEGF compounds suggest that some patients may benefit from substituting the anti-VEGF in cases of an unsatisfactory response to an initial molecule. Although local side effects, including increased risk of geographic atrophy, and systemic effects, including vascular accidents, have been suggested, these risks remain low, specially compared to the benefits of the treatment. Differences in safety between anti-VEGF are theoretically possible but unproven.

Evaluation of cardiovascular biomarkers in patients with age-related wet macular degeneration

AIM

To evaluate levels of homocysteine, asymmetric dimethylarginine (ADMA), and nitric oxide (NO), as well as activity of endothelial NO synthase (eNOS), in patients with age-related macular degeneration (AMD).

METHODS

The levels of homocysteine, ADMA, and NO and activity of eNOS in patients who were diagnosed with wet AMD by fundus fluorescein angiography (n=30) were compared to a control group with no retinal pathology (n=30).

RESULTS

Levels of homocysteine and ADMA were found to be significantly higher in the wet AMD group than in the control group (P<0.001), whereas NO levels and eNOS activity were higher in the control group (P<0.001). In the wet AMD group, we detected a 2.64- and 0.33-fold increase in the levels of ADMA and homocysteine, respectively, and a 0.49- and 2.41-fold decrease in the eNOS activity and NO level, respectively.

CONCLUSION

Elevated levels of homocysteine and ADMA were observed in patients with wet AMD. Increased ADMA may be responsible for the diminished eNOS activity found in these patients, which in turn contributes to the decrease in NO levels, which likely plays a role in the pathogenesis of AMD.

Measurement of retinal function with flash-electroretinography in Chinese patients with hyperlipidemia

BACKGROUND

We used flash electroretinography (F-ERG) to determine if retinal function was impaired in patients with hyperlipidemia, including visual acuity and fundus morphological changes, and to identify predictors of impaired retinal function in hyperlipidemia patients.

METHODS

This was a prospective case-control study (Shanghai, China; February 2011 to January 2012) in 696 hyperlipidemia patients and 136 healthy controls. Exclusion criteria included best-corrected visual acuity <0.6, previous intraocular surgery, and chronic comorbidities. Each participant underwent a comprehensive series of ophthalmologic examinations, and standard F-ERG examination. Data were analyzed using t-tests and multivariate analysis.

RESULTS

Six hundred and twenty-six hyperlipidemia patients (57.69 ± 14.01 years; 59.58% female) and 120 healthy controls (55.13 ± 14.03 years; 60% female) were included in the final analysis. After adjustment for age and gender using multivariate covariance analysis, F-ERG result revealed significantly lower response amplitudes in the hyperlipidemia group (P < 0.05), and longer implicit times (P < 0.05) than the control group. F-ERG parameters were significantly different between the two groups. Stepwise multiple linear regression analysis showed that serum LDL levels (P < 0.001), BMI (P < 0.001), duration of hyperlipidemia (P < 0.001), and serum HDL levels (P = 0.03) were negatively correlated with ΣOps.

CONCLUSION

The present study suggests that the retinal function of hyperlipidemia patients was significantly lower than in healthy controls, even before the occurrence of pathological changes in the fundus.

Refractive error and risk of early or late age-related macular degeneration: a systematic review and meta-analysis

OBJECTIVE

To summarize relevant evidence investigating the associations between refractive error and age-related macular degeneration (AMD).

DESIGN

Systematic review and meta-analysis.

METHODS

We searched Medline, Web of Science, and Cochrane databases as well as the reference lists of retrieved articles to identify studies that met the inclusion criteria. Extracted data were combined using a random-effects meta-analysis. Studies that were pertinent to our topic but did not meet the criteria for quantitative analysis were reported in a systematic review instead.

MAIN OUTCOME MEASURES

Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between refractive error (hyperopia, myopia, per-diopter increase in spherical equivalent [SE] toward hyperopia, per-millimeter increase in axial length [AL]) and AMD (early and late, prevalent and incident).

RESULTS

Fourteen studies comprising over 5800 patients were eligible. Significant associations were found between hyperopia, myopia, per-diopter increase in SE, per-millimeter increase in AL, and prevalent early AMD. The pooled ORs and 95% CIs were 1.13 (1.06-1.20), 0.75 (0.56-0.94), 1.10 (1.07-1.14), and 0.79 (0.73-0.85), respectively. The per-diopter increase in SE was also significantly associated with early AMD incidence (OR, 1.06; 95% CI, 1.02-1.10). However, no significant association was found between hyperopia or myopia and early AMD incidence. Furthermore, neither prevalent nor incident late AMD was associated with refractive error. Considerable heterogeneity was found among studies investigating the association between myopia and prevalent early AMD (P = 0.001, I2 = 72.2%). Geographic location might play a role; the heterogeneity became non-significant after stratifying these studies into Asian and non-Asian subgroups.

CONCLUSION

Refractive error is associated with early AMD but not with late AMD. More large-scale longitudinal studies are needed to further investigate such associations.

Outer retinal atrophy after regression of subretinal drusenoid deposits as a newly recognized form of late age-related macular degeneration

PURPOSE

To investigate the long-term clinical course of eyes with pseudodrusen appearance caused by subretinal drusenoid deposits.

METHODS

Eyes from the original study identifying subretinal deposits of material as the cause of pseudodrusen appearance were evaluated in a retrospective study of outer retinal morphology. The distance between the inner plexiform layer and the retinal pigment epithelium, termed the photoreceptor length, was measured from optical coherence tomography approximately 2 mm superior to the fovea at baseline and at follow-up visits. The choroidal thickness was measured directly under this retinal area.

RESULTS

Of the 21 eyes available for follow-up, 9 (42.9%) eventually developed choroidal neovascularization over a mean 2.9-year follow-up period. Regression of subretinal drusenoid deposits was seen in 9 eyes (42.9%) as well. Those with regression of subretinal drusenoid deposits had a decrease in the photoreceptor length with the final photoreceptor length being 74.4% of the initial length (P < 0.001). In eyes with regression, the underlying choroid was 81.4% of its initial value (P = 0.01) at the final follow-up. Eyes with regression also showed loss of the ellipsoid band. Eyes without regression had no change in photoreceptor length, choroidal thickness, or outer retinal architecture.

CONCLUSION

Eyes with regression of subretinal drusenoid deposits develop outer retinal atrophy and loss of the underlying choroidal thickness. This finding seems common in eyes having pseudodrusen and represents a late form of age-related macular degeneration that is not in current classification systems. Further study is needed to determine both the true prevalence and the effects on visual function.

Role of statins in the development and progression of age-related macular degeneration

PURPOSE

To determine if statins are associated with the development or progression of age-related macular degeneration (AMD).

METHODS

A large, national insurance claims database was reviewed to identify individuals aged 60 years or older who were enrolled for ≥2 years and had ≥1 visits to an eye provider. Prescription claims for statins within a 24-month look-back period and outpatient lipid laboratory values were also reviewed. Cox regression analysis was used to determine whether statin use was associated with the development of nonexudative or exudative AMD or progressing from nonexudative to exudative AMD.

RESULTS

Of the 107,007 beneficiaries eligible for the nonexudative AMD analysis, 4,647 incident cases of nonexudative AMD occurred. Seven hundred and ninety-two incident cases of exudative AMD were found among the 113,111 beneficiaries eligible for the exudative AMD analysis. Of the 10,743 beneficiaries with known nonexudative AMD eligible for the progression model, 404 progressed to exudative AMD during their time in the plan. After multivariable analysis, statin use was not associated with the development of nonexudative AMD (P > 0.05). Statin use of >12 months was associated with an increased hazard for developing exudative AMD (P < 0.005). Among those taking statins, only enrollees with the highest lipid levels had an increased hazard of developing exudative AMD (P < 0.05).

CONCLUSION

In those with elevated lipid levels, >1 year of statin use was associated with an increased hazard for exudative AMD. Lipid status influences the relationship between statins and the risk of AMD. Because of a number of limitations in study design, these observations warrant further study and should not be the rationale for any changes in the use of statins to treat dyslipidemias.

Asian Age-Related Macular Degeneration: Current Concepts and Gaps in Knowledge

Data on the epidemiology and treatment of age-related macular degeneration (AMD) in Asian populations have been scarce. Recently, significant advances in the current knowledge of AMD in Asia have been made, but deficiencies in important areas remain. Epidemiological data on AMD in those 80 years or older are lacking.There are also few incidence data on AMD or polypoidal choroidal vasculopathy (PCV), an important variant of AMD that seems to be more common in Asia. The risk factors for PCV have not been clearly defined to the extent that those for AMD have. No trials of nutritional supplementation for AMD prevention in Asia exist, and there is also a lack of long-term clinical trial data on combination therapy for PCV and indeed very few trial data on PCV. These represent opportunities for future research. With aging populations in Asia, increased data on the prevalence, risk factors, prevention, and treatment of AMD and PCV in Asian populations will be needed to formulate evidence-based public health and clinical guidelines.

CFB/C2 gene polymorphisms and risk of age-related macular degeneration: a systematic review and meta-analysis

PURPOSE

To investigate whether the polymorphisms of CFB/C2 gene are associated with age-related macular degeneration (AMD), and to evaluate the magnitude of gene effect.

METHODS

We performed a meta-analysis of the association between four SNPs in CFB/C2 gene (rs9332739, rs547154, rs4151667, and rs641153) and risk of AMD using data from 15 case-control studies involving 8905 subjects. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed- and random-effects models. The Q and I(2) statistics were used to evaluate between-study heterogeneity. Harbord's modified test was used to detect small study effects. Sensitivity analysis, cumulative meta-analysis, and meta-regression were also performed.

RESULTS

For rs9332739, rs547154, rs4151667, and rs641153, the pooled ORs in a dominant genetic model were 0.474 (fixed effects, P < 0.001, 95% CI 0.378-0.596), 0.399 (random effects, 95% CI 0.289-0.551, P < 0.001), 0.496 (fixed effects, 95% CI 0.390-0.632, P < 0.001), and 0.557 (random effects, P = 0.008, 95% CI 0.362-0.856), respectively. These results suggested that variant alleles of all the four SNPs has significant protective effect against AMD. Contour-enhanced funnel plots and Harbord's test showed moderate small study effects for rs9332739 and rs4151667. Heterogeneity were found for rs547154 and rs641153, subgroup analysis suggested that ethnicity was the main source for heterogeneity. Stratification by ethnicity indicated stronger protective effects of rare alleles in Caucasians. Genotype distribution analysis also suggested that frequencies of rare homozygous genotype were higher in Caucasian group.

CONCLUSIONS

Our meta-analysis indicated strong protective effects of the variant alleles of four SNPs in CFB/C2 gene (rs9332739, rs547154, rs4151667, and rs641153) against AMD. The disease risk descended to nearly one half for individuals carrying at least one copy of the rare alleles. The protective effects seemed to be stronger in Caucasians, of which the genotype frequencies were also higher.

Randomized clinical trial France DMLA2: effect of trimetazidine on exudative and nonexudative age-relatedmacular degeneration

PURPOSE

To evaluate the effect of trimetazidine (TMZ) in a randomized, double-blind, placebo-controlled clinical trial on the occurrence of choroidal neovascularization or geographic atrophy in age-related macular degeneration.

METHODS

A total of 1,086 patients from France, Belgium, and Spain with soft drusen and/or retinal pigment epithelium abnormalities in the study eye and choroidal neovascularization in the contralateral eye were randomly assigned to receive orally placebo or TMZ 70 mg daily (35 mg × 2) and followed-up for 3 years to 5 years.

RESULTS

Treatment duration ranged between 0.4 months and 67.8 months with a mean ± SD of 38 ± 16 months. Three hundred and fifty-eight patients developed choroidal neovascularization (incidence per 100 patient-years: TMZ 10.86; placebo 11.13). Trimetazidine did not prevent the choroidal neovascularization (hazard ratio = 0.97; 95% confidence interval, 0.77-1.20; P = 0.781). However, there was a trend favoring TMZ for retinal atrophy, a secondary endpoint (HR = 0.76; 95% confidence interval, 0.56-1.02; P = 0.069). Overall, the difference in atrophy incidence between TMZ and placebo was not statistically different. Differences within some prespecified subgroups of patients showed superiority of TMZ in men (HR = 0.50; 95% confidence interval, 0.28-0.89; p = 0.016), in patients aged ≤75 years (HR = 0.58; 95% confidence interval, 0.38-0.88; p = 0.010), or in patients presenting with isolated pigmentary changes (HR = 0.19; 95% confidence interval, 0.05-0.70; p = 0.005).

CONCLUSION

Trimetazidine failed to prevent choroidal neovascularization. Subgroup analyses suggest that this drug could be tested as preventive therapy for geographic atrophy, although the overall comparison showed no statistically significant differences in the progression of geographic atrophy.

Serum paraoxonase phenotype distribution in exudative age-related macular degeneration and its relationship to homocysteine and oxidized low-density lipoprotein

PURPOSE

Disequilibrium between oxidative stress and antioxidant levels has been proposed as an important case of exudative age-related macular degeneration (AMD). The aim of the present study was to investigate homocysteine (Hcy) level and antioxidant paraoxonase 1 (PON1) activity within its phenotypes together with oxidized low-density lipoprotein (OX-LDL) levels in the patients with exudative AMD.

METHODS

Serum PON1 activity and plasma Hcy and OX-LDL levels were analyzed in 45 exudative AMD patients and compared with 45 healthy controls. Paraoxonase 1 activity was measured in serum using paraoxon and phenylacetate as substrates. The PON1 phenotype was determined using double-substrate method. Homocysteine and OX-LDL levels were determined by enzyme-linked immunosorbent assay method.

RESULTS

The distribution of PON1 phenotypes was significantly different between the patients with exudative AMD and control subjects (chi-square = 6.17, P = 0.01). AA phenotype with low activity was significantly more frequent in exudative AMD patients compared with healthy subjects (62.2% vs. 35.6%, respectively). Other phenotype frequencies in the patients compared with controls were as AB phenotype (intermediate activity) 28.9% versus 46.7% and BB phenotype (high activity) 8.9% versus 17.8%, respectively. Except in BB phenotype (P = 0.2), patients with AA and AB phenotypes had higher plasma Hcy levels in comparison to those of controls (P = 0.02 and P = 0.03, respectively). The mean OX-LDL levels, in all 3 phenotypes (P < 0.05), and OX-LDL/high-density lipoprotein ratio, in AA and AB phenotypes (P = 0.001, P = 0.1, respectively) but not in BB (P = 0.1), were significantly higher in the patients than controls. No significant differences in comparison of Hcy and OX-LDL levels between 3 PON1 phenotypes in both control (P = 0.6 for Hcy, P = 0.7 for OX-LDL) and patients (P = 0.8 for Hcy, P = 0.6 for OX-LDL) were found

CONCLUSION

Increased plasma OX-LDL levels and ratios of OX-LDL/high-density lipoprotein, as biomarkers of lipoprotein oxidative stress, higher levels of Hcy, as oxidant agent, and more common low or intermediate PON1 activity in patients with exudative AMD, compared with controls, indicate that PON1 activity is insufficient to explain the increased oxidative stress observed in exudative AMD.

An association between environmental factors and the IVS4+44C>A polymorphism of the DMT1 gene in age-related macular degeneration

Background

Age-related macular degeneration (AMD) is an ocular disease affecting macula — the central part of the retina, resulting in the degeneration of photoreceptors and retinal epithelium and causing severe central vision impairment. The pathophysiology of the disease is not completely known, but a significant role is attributed to genetic factors. The contribution of oxidative stress in AMD as a trigger of the degenerative process is well-established. Iron ions may act as a source of reactive oxygen species; therefore, maintaining iron homeostasis is important for redox balance in the organism. Diversity in iron homeostasis genes may counterpart in unbalanced redox state, and thus be involved in AMD pathophysiology.

Methods

In this work, we searched for an association between some single nucleotide polymorphisms in the divalent metal transporter 1 (DMT1) gene intronic IVS4+44C>A (rs224589) and 3’-UTR c.2044T>C (rs2285230) and environmental factors and AMD. Genotyping was performed using the PCR-RFLP method. DNA was obtained from 436 AMD patients and 168 controls.

Results

We did not find any association between the genotypes of the two polymorphisms and AMD occurrence. However, we observed that AMD patients living in a rural environment and having the CC genotype of the IVS4+44C>A polymorphism had an increased risk of AMD, while individuals with the CA genotype or the A allele had a decreased risk of the disease. Moreover, in male AMD patients the C allele increased the risk of the disease, while the AA genotype decreased it.

Conclusions

These results suggest that the VS4+44C>A polymorphism of the DMT1 gene may interact with place of living and gender to modulate the risk of AMD.

Age-related macular degeneration with discordant late stage phenotypes in monozygotic twins

PURPOSE

Age-related macular degeneration (AMD) is a complex disease caused by genetic and environmental factors. Monozygotic twins with late stage AMD provide an opportunity to evaluate the role of environmental factors on a genetically uniform background.

METHODS

Monozygosity was determined in four twin pairs by genotyping 15 highly polymorphic tetranucleotide repeat markers. Clinically, the monozygotic twin pairs were evaluated by ophthalmologic examination, fundus autofluorescence (FAF) imaging, and, upon suspicion of choroidal neovascular membranes, by fluorescein angiography. Twin pairs were followed over a period of 4-8 years.

RESULTS

Genetically confirmed monozygotic twins with early stages of AMD reveal striking symmetry of early macular pathology. Upon progression to late stage AMD each twin pair developed a discordant phenotype with respect to disease onset and specific phenotype as choroidal neovascularization (CNV) and geographic atrophy (GA).

CONCLUSIONS

Genetic risk variants are known to predispose to the development of AMD. Course and visual outcome of the disease, however, appear to be influenced by environmental factors rather than genetic determinants.

Identifying subtypes of patients with neovascular age-related macular degeneration by genotypic and cardiovascular risk characteristics

BACKGROUND

One of the challenges in the interpretation of studies showing associations between environmental and genotypic data with disease outcomes such as neovascular age-related macular degeneration (AMD) is understanding the phenotypic heterogeneity within a patient population with regard to any risk factor associated with the condition. This is critical when considering the potential therapeutic response of patients to any drug developed to treat the condition. In the present study, we identify patient subtypes or clusters which could represent several different targets for treatment development, based on genetic pathways in AMD and cardiovascular pathology.

METHODS

We identified a sample of patients with neovascular AMD, that in previous studies had been shown to be at elevated risk for the disease through environmental factors such as cigarette smoking and genetic variants including the complement factor H gene (CFH) on chromosome 1q25 and variants in the ARMS2/HtrA serine peptidase 1 (HTRA1) gene(s) on chromosome 10q26. We conducted a multivariate segmentation analysis of 253 of these patients utilizing available epidemiologic and genetic data.

RESULTS

In a multivariate model, cigarette smoking failed to differentiate subtypes of patients. However, four meaningfully distinct clusters of patients were identified that were most strongly differentiated by their cardiovascular health status (histories of hypercholesterolemia and hypertension), and the alleles of ARMS2/HTRA1 rs1049331.

CONCLUSIONS

These results have significant personalized medicine implications for drug developers attempting to determine the effective size of the treatable neovascular AMD population. Patient subtypes or clusters may represent different targets for therapeutic development based on genetic pathways in AMD and cardiovascular pathology, and treatments developed that may elevate CV risk, may be ill advised for certain of the clusters identified.

Clinical risk factors for age-related macular degeneration: a systematic review and meta-analysis

BACKGROUND

Age-related macular degeneration (AMD) is the leading cause of blindness in Western countries. Numerous risk factors have been reported but the evidence and strength of association is variable. We aimed to identify those risk factors with strong levels of evidence which could be easily assessed by physicians or ophthalmologists to implement preventive interventions or address current behaviours.

METHODS

A systematic review identified 18 prospective and cross-sectional studies and 6 case control studies involving 113,780 persons with 17,236 cases of late AMD that included an estimate of the association between late AMD and at least one of 16 pre-selected risk factors. Fixed-effects meta-analyses were conducted for each factor to combine odds ratio (OR) and/or relative risk (RR) outcomes across studies by study design. Overall raw point estimates of each risk factor and associated 95% confidence intervals (CI) were calculated.

RESULTS

Increasing age, current cigarette smoking, previous cataract surgery, and a family history of AMD showed strong and consistent associations with late AMD. Risk factors with moderate and consistent associations were higher body mass index, history of cardiovascular disease, hypertension, and higher plasma fibrinogen. Risk factors with weaker and inconsistent associations were gender, ethnicity, diabetes, iris colour, history of cerebrovascular disease, and serum total and HDL cholesterol and triglyceride levels.

CONCLUSIONS

Smoking, previous cataract surgery and a family history of AMD are consistent risk factors for AMD. Cardiovascular risk factors are also associated with AMD. Knowledge of these risk factors that may be easily assessed by physicians and general ophthalmologists may assist in identification and appropriate referral of persons at risk of AMD.

Association of risk factors for choroidal neovascularization in age-related macular degeneration with decreased foveolar choroidal circulation

PURPOSE

To investigate the relationship between known risk factors for age-related macular degeneration (AMD) progression and foveolar choroidal circulation in eyes with nonexudative AMD.

DESIGN

Cross-sectional study of nonexudative AMD.

METHODS

Laser Doppler flowmetry measurements of relative choroidal blood velocity, choroidal blood volume (ChBVol), and choroidal blood flow (ChBFlow) were obtained in the center of the fovea of 273 study eyes of 204 AMD patients investigated at the Scheie Eye Institute, University of Pennsylvania Medical School. All study eyes had visual acuity of 20/40 or better, good fixation, no other intraocular pathologic features, and no evidence of choroidal neovascularization. RPE hypertrophy was determined from color fundus photographs by trained masked graders at the Scheie Image Reading Center. Correlation analysis and multivariate linear regression analysis with adjustments for significant covariates were carried out.

RESULTS

A significant inverse correlation was observed between age and ChBFlow (r = -0.36; P < .0001), and ChBVol (r = -0.28; P < .0001), but not for choroidal blood velocity. A significant inverse correlation was observed between spherical equivalent and ChBFlow (r = -0.21; P = .006) and ChBVol (r = -0.14; P = .04), but not for choroidal blood velocity. ChBFlow and ChBVol were significantly lower in patients with a history of hypertension (P < or = .003) and in eyes with retinal pigment epithelium hypertrophy (P < or = .04), respectively.

CONCLUSIONS

All the above-described risk factors for AMD development and progression are associated with decreased choroidal circulatory parameters, suggesting that decreases in choroidal circulatory parameters may be involved in the development of AMD.

ARMS2/HTRA1 and CFH polymorphisms are not associated with choroidal neovascularization in highly myopic eyes of the elderly Japanese population

PURPOSE

The purpose of this study was to investigate whether the genetic risk factors of age-related macular degeneration (AMD) are associated with the development of choroidal neovascularization (CNV) in highly myopic eyes of elderly Japanese.

METHODS

Highly myopic elderly Japanese patients with and without CNV were genotyped for three AMD-associated single nucleotide polymorphisms (SNPs), namely rs10490924 (A69S) of ARMS2, rs11200638 of HTRA1, and rs1061170 (Y402H) of complement factor H (CFH), with the TaqMan SNP assay. One hundred and eighty-three unrelated highly myopic (axial lengths>26.00 mm or refractive errors>-6.0 diopters) Japanese patients with CNV who were >or=50 years of age (mean age+/-standard deviation of 62.7+/-6.3 years) and 170 highly myopic patients without CNV who were >or=50 years old (62.3+/-7.1 years) were studied. The differences in the genotypic distributions for the three SNPs between the two groups were tested with the Trend chi2 test, and logistic regression analyses were performed for age and gender adjustment.

RESULTS

No significant difference was detected in the distribution of the three SNPs, rs10490924 (P>0.1), rs11200638 (P>0.1), and rs1061170 (P>0.5), between the two groups even after adjustments for age and gender differences.

CONCLUSION

The genetic risk factors of AMD related to these SNPs do not contribute significantly to the development of CNV in a highly myopic elderly Japanese population.

Prevalence and progression of myopic retinopathy in Chinese adults: the Beijing Eye Study

PURPOSE

To determine the prevalence and progression of myopic retinopathy in Chinese adults.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

The Beijing Eye Study 2001 included 4439 subjects of 5324 individuals who were invited to participate (response rate, 83.4%); the eligibility criterion was an age of 40+ years. The study was repeated in 2006, with 3251 subjects (73.2%) participating.

METHODS

The participants underwent a detailed eye examination, including fundus photography. Myopic retinopathy was defined by posterior staphylomata, lacquer cracks, Fuchs' spot of the macula, and myopic chorioretinal atrophy at the posterior pole. Parapapillary atrophy was assessed separately.

MAIN OUTCOME MEASURES

Prevalence of myopic retinopathy and its change during a follow-up of 5 years.

RESULTS

After exclusion of pseudophakic or aphakic eyes, and eyes without assessable fundus photographs, 4319 subjects (97.3%) were included in the present study. Myopic retinopathy was present in 198 eyes (2.3%+/-0.2%; 95% confidence interval [CI], 2.0-2.6) of 132 participants (3.1%). Myopic retinopathy was significantly associated with higher age (P<0.001), worse best-corrected visual acuity (P<0.001), deeper anterior chamber (P = 0.04), larger optic disc (P<0.001), less age-related macular degeneration (P = 0.02; odds ratio [OR] 0.90), and greater prevalence of open-angle glaucoma (P<0.001; OR 4.42). Myopic retinopathy was not associated significantly (P>0.20) with body height and weight, gender, rural versus urban region of residence, level of education, intraocular pressure, or central corneal thickness. The prevalence of myopic retinopathy increased significantly (P<0.001) with increasing myopic refractive error, from 3.8% in eyes with a myopic refractive error of < -4.0 diopters to 89.6% in eyes with a myopic refractive error of at least -10.0 diopters. At the 5-year follow-up examination, enlargement of the chorioretinal atrophy at the posterior fundus was observed in 9% of the eyes.

CONCLUSIONS

Myopic retinopathy was present in 3.1% of subjects aged 40+ years who resided in the Greater Beijing area. Myopic retinopathy was associated with increased age, worse best-corrected visual acuity, deeper anterior chamber, larger optic disc, less age-related macular degeneration, and higher prevalence of open-angle glaucoma.

Ocular risk factors for age-related macular degeneration: the Los Angeles Latino Eye Study

PURPOSE

To assess the association between ocular factors and age-related macular degeneration (AMD) in Latinos.

DESIGN

Population-based, cross-sectional study of 6357 self-identified Latinos aged 40 years and older.

METHODS

Ophthalmic examination included subjective refraction, measurement of axial length, evaluation of iris color, Lens Opacities Classification System II (LOCS II) grading of cataracts, and stereoscopic macular photographs for AMD lesions. Generalized estimating equation analysis incorporated data from both eyes to estimate odds ratios (OR) adjusted for covariates.

RESULTS

After controlling for confounders (age, gender, and smoking), prior cataract surgery was associated with advanced AMD (OR, 2.8; 95% CI, 1.01, 7.8), increased retinal pigment (OR, 1.6; 95% CI, 1.02, 1.5), and retinal pigment epithelial depigmentation (OR, 2.2; 95% CI, 1.1, 4.4). The presence of any lens opacity was associated with soft drusen (OR, 1.2; 95% CI, 1.002, 1.5). Longer axial length (per mm) was associated with decreased odds of soft drusen, increased retinal pigment, and geographic atrophy (GA) (ORs, 0.8 [95% CI, 0.7, 0.9], 0.8 [95% CI, 0.7, 0.9], 0.7 [95% CI, 0.5, 0.9], respectively). Myopia was inversely associated with soft drusen (OR, 0.8; 95% CI, 0.7, 0.99). Lighter-colored irises were associated with GA (OR, 5.0; 95% CI, 1.0, 25.3).

CONCLUSIONS

Cross-sectional associations of ocular factors such as cataract, cataract surgery, and refractive errors with early AMD lesions found in Latinos are consistent with those in non-Hispanic Whites. Additionally, prior cataract surgery was associated with advanced AMD.

Effect of zeaxanthin and antioxidant supplementation on vascular endothelial growth factor (VEGF) expression in apolipoprotein-E deficient mice

PURPOSE

Apolipoprotein E(-/-) deficient (apoE(-/-)) mice develop hypercholesterolemia, atherosclerosis, and retinal alterations. We studied the oxidative status and vascular endothelial growth factor (VEGF) expression in murine retinal pigment epithelium-choroid (RPE) and Bruch's membrane (BM) ultrastructure and the effect of zeaxanthin.

METHODS

Ten 6-month-old C57BL/6 and 40 apoE(-/-) mice were divided into four groups (n = 10 each) and fed different diets for 12 weeks based on body weight: wild type (WT) and apoE(-/-) (AE-Con) mice standard rodent chow; apoE(-/-) mice (AES) standard rodent chow with ascorbate (800 mg/kg), tocopherol (1053 mg/kg), and zinc (135 mg/kg); and apoE(-/-) mice the last diet plus zeaxanthin with either 0.4 g/kg (AES-Z04) or 4 g/kg feed (AES-Z4).

RESULTS

Plasma total cholesterol (TC) and triglycerides (TG) and urine lipid peroxidation (isoprostanes) were measured. VEGF expression was determined in RPE-choroid homogenates. Zeaxanthin uptake was assessed in liver and retina by high-performance liquid chromatography; the retinal ultrastructure was analyzed by electron microscopy. AE-Con mice had higher plasma TC (p < 0.001) and TG (p < 0.001) values than WT mice. AE-Con mice had higher RPE-choroid-VEGF levels than WT mice (p < 0.05), BM thickness (p < 0.001) and presence of basal laminar deposits (BLamD). AES-Z4 resulted in lower urinary isoprostanes (p = 0.054) and lower VEGF expression in the RPE-choroid (p < 0.01). BM in the AES-Z4 animals had less confluent BLamD than AE-Con, AES, or AES-Z04 animals.

CONCLUSIONS

We have reported that supplementation with zeaxanthin and antioxidants may delay or reverse alterations in the RPE and deposits in BM, and reduced VEGF expression observed in apoE(-/-) mice.

Risk factors for age-related maculopathy

Age-related maculopathy (ARM) is the leading cause of blindness in the elderly. Although beneficial therapeutic strategies have recently begun to emerge, much remains unclear regarding the etiopathogenesis of this disorder. Epidemiologic studies have enhanced our understanding of ARM, but the data, often conflicting, has led to difficulties with drawing firm conclusions with respect to risk for this condition. As a consequence, we saw a need to assimilate the published findings with respect to risk factors for ARM, through a review of the literature appraising results from published cross-sectional studies, prospective cohort studies, case series, and case control studies investigating risk for this condition. Our review shows that, to date, and across a spectrum of epidemiologic study designs, only age, cigarette smoking, and family history of ARM have been consistently demonstrated to represent risk for this condition. In addition, genetic studies have recently implicated many genes in the pathogenesis of age-related maculopathy, including Complement Factor H, PLEKHA 1, and LOC387715/HTRA1, demonstrating that environmental and genetic factors are important for the development of ARM suggesting that gene-environment interaction plays an important role in the pathogenesis of this condition.