Racial/ethnic differences in age-related maculopathy. Third National Health and Nutrition Examination Survey

Current Views on Chr10q26 Contribution to Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of blindness in the global aging population. Familial aggregation and genome-wide association (GWA) studies have identified gene variants associated with AMD, implying a strong genetic contribution to AMD development. Two loci, on human Chr 1q31 and 10q26, respectively, represent the most influential of all genetic factors. While the role of CFH at Chr 1q31 is well established, uncertainty remains about the genes ARMS2 and HTRA1, at the Chr 10q26 locus. Since both genes are in strong linkage disequilibrium, assigning individual gene effects is difficult. In this chapter, we review current literature about ARMS2 and HTRA1 and their relevance to AMD risk. Future studies will be necessary to unravel the mechanisms by which they contribute to AMD.

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

PURPOSE

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

METHODOLOGY

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

RESULTS

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

CONCLUSION

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

Comparison of risk allele frequencies of single nucleotide polymorphisms associated with age-related macular degeneration in different ethnic groups

BACKGROUND

The prevalence of age-related macular degeneration (AMD) varies from 6.8 to 18.3% for all forms of AMD and from 0.6 to 2.6% for late AMD according to race, suggesting the existence of genetic differences among races. The purpose of this study was to determine the genetic causes of differences in the prevalence of AMD among individuals of different races.

METHODS

We collected 138 AMD-associated single nucleotide polymorphisms (SNPs) from a genome-wide association studies catalog. Their population-level allele frequencies were derived based on the 1000 Genomes Project and Korean Reference Genome Database. We used Fisher's exact tests to assess whether the effect allele at a given SNP was significantly enriched or depleted in the database.

RESULTS

European, American, and South Asian populations showed similar heatmap patterns, whereas East Asian, and Korean populations had distinct patterns. Korean populations exhibited patterns that were different from those of the other groups; rs5754227 (SYN3), rs1626340 (TGFBR1/COL15A1), rs3750846(ARMS2/HTRA1), and rs9564692 (B3GALTL) were enriched, whereas rs2230199 (C3) and rs73036519 (EXOC3L2/MARK4) were depleted in Koreans; these SNPs are associated with late AMD. The genetic risk score calculated from allele frequencies was not less in East Asians than in Europeans.

CONCLUSION

The prevalence of AMD is lower in Asians than in Europeans. However, our study showed that genetic risk scores in East Asians were similar to those in Europeans, which may explain why the global projected number of people with AMD by 2040 is in largest for East Asians, including Koreans.

The Effects of Adjuvant Tamoxifen Use on Macula Pigment Epithelium Optical Density, Visual Acuity and Retinal Thickness in Patients with Breast Cancer

Purpose: We aimed to compare best corrected visual acuity, macular pigment optical density and macular thickness in patients with breast cancer, who received oral adjuvant hormone therapy.Materials and Methods: We enrolled consecutive eligible patients with breast cancer who were receiving regular medical tamoxifen treatment. The participants were divided into two groups as cases and controls. Best-corrected visual acuity and retinal thickness were examined. Macular pigment optical density was measured by fundus reflectometry using the one-wavelength reflection method. The output parameters included max optical density, mean optical density, volume and area of the right eye.Results: A total of 104 eyes, cases (n: 50) and controls (n: 54) were included in the study. Mean age in cases was 49.95 ± 9.2 years and 50.21 ± 9.3 years in controls (p = .151). The mean foveal optical density and the maximum optical density differed between cases (0.13 ± 0.03 density units (DU)/0.35 ± 0.07 DU) and controls (0.18 ± 0.04 DU/0.41 ± 0.06 DU) (p = .002/p = .009). Macular pigment optical density volume was 8102.84 ± 2412.67 in cases versus 8280.18 ± 2904.56 in controls (p = .034), and mean MPOD area was 59567.79 ± 11538.06 in cases versus 61748.14 ± 10591.19 in controls (p = .023). The best corrected visual acuity and retinal thickness were similar in both groups (p > .05).Conclusions: Patients in care of oral tamoxifen therapy were found to have significantly reduced macular pigment optical density. In addition, higher drug use duration correlated significantly with reduced macular pigment optical density, suggesting that the poor long-term effects may play a role in macular pigment absorption and incorporation in the retinal tissue.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

Laser Photocoagulation of Soft Drusen in Early Age-Related Maculopathy (Arm). the One-Year Results of a Prospective, Randomised Trial

In this prospective, randomised trial, 19 patients (mean age 72.2 +/- 6.6 years) with soft drusen maculopathy and good visual acuity (0.93 +/- 0.1) were treated with argon green laser photocoagulation. Fundus colour photography and fluorescein angiography were performed at study entry and after 3, 6 and 12 months. Nineteen patients (mean age 68.5 +/- 6.2 years) with visual acuity 0.95 +/- 0.1 and similar fundus changes served as a control group. The area occupied by drusen within a circular zone was calculated in the fundus colour photographs (radius 2500 microns) and in the angiograms (radius 1250 microns). Mean drusen area of the treatment group did not differ from that of the control group at study entry (p > 0.5-0.7). In the treatment group, mean drusen area had decreased significantly from 7.87% to 2.93% (p = 0.00013) and from 19.22% to 7.15% (p < 0.0001) at 12 months respectively in the colour photographs and in the angiograms. Visual acuity and colour contrast sensitivity did not change. No complications were seen in the treated group. In the control group, mean drusen area increased from 8.33% to 10.69% and from 17.41% to 22.05%, respectively. These differences did not reach statistical significance. When comparing the 12-month change in drusen area in the two groups, significant differences were found both in fundus colour photographs and angiograms (p < 0.001). In the control group, mean visual acuity decreased to 0.89 +/- 0.1 (p = 0.008) and mean colour contrast threshold for the tritan axis increased significantly (p = 0.044), indicating impairments of retinal function. Three patients in the control group advanced to an exudative stage of the disease.

Prevention of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) compromises quality of life. However, the available therapeutic options are limited. This has led to the identification of modifiable risk factors to prevent the development or alter the natural course and prognosis of AMD. The identification and modification of risk factors has the potential for greater public health impact on reducing morbidity from AMD. Likewise, identifying the imaging clues and genetic clues could serve as a guide to recognizing the propensity for progression to severe and end stages of the disease. Several attempts, both successful and unsuccessful, have been made for interventions that could delay the progression of AMD. Of these, pharmacological interventions have shown promising results. The Age-Related Eye Disease Study 1 and 2 have shown the beneficial role of antioxidants in a selected group of patients.

Recent developments in age-related macular degeneration: a review

Background

Visual impairment in elderly people is a considerable health problem that significantly affects quality of life of millions worldwide. The magnitude of this issue is becoming more evident with an aging population and an increasing number of older individuals.

Objective

The objective of this article was to review the clinical and pathological aspects of age-related macular degeneration (AMD), diagnostic tools, and therapeutic modalities presently available or underway for both atrophic and wet forms of the disease.

Methods

An online review of the PubMed database was performed, searching for the key words. The search was limited to articles published since 1980 to date.

Results

Several risk factors have been linked to AMD, such as age (>60 years), lifestyle (smoking and diet), and family history. Although the pathogenesis of AMD remains unclear, genetic factors have been implicated in the condition. Treatment for atrophic AMD is mainly close observation, coupled with nutritional supplements such as zinc and antioxidants, whereas treatment of wet AMD is based on targeting choroidal neovascular membranes.

Conclusion

Identification of modifiable risk factors would improve the possibilities of preventing the progression of AMD. The role of anti-vascular endothelial growth factor (anti-VEGF) agents has transformed the therapeutic approach of the potentially blinding disease “wet AMD” into a more favorable outcome.

Surgery for cataracts in people with age-related macular degeneration

BACKGROUND

Cataract and age-related macular degeneration (AMD) are common causes of decreased vision that often occur simultaneously in people over age 50. Although cataract surgery is an effective treatment for cataract-induced visual loss, some clinicians suspect that such an intervention may increase the risk of worsening of underlying AMD and thus have deleterious effects on vision.

OBJECTIVES

The objective of this review was to evaluate the effectiveness and safety of cataract surgery compared with no surgery in eyes with AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 11), Ovid MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily (January 1946 to December 2016), Embase (January 1980 to December 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to December 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 2 December 2016.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-randomized trials that enrolled participants whose eyes were affected by both cataract and AMD in which cataract surgery was compared with no surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated the search results against the inclusion and exclusion criteria. Two review authors independently extracted data, assessed risk of bias for included studies, and graded the certainty of evidence. We followed methods as recommended by Cochrane.

MAIN RESULTS

We included two RCTs with a total of 114 participants (114 study eyes) with visually significant cataract and AMD. We identified no ongoing trials. Participants in each RCT were randomized to immediate cataract surgery (within two weeks of enrollment) or delayed cataract surgery (six months after enrollment). The risk of bias was unclear for most domains in each study; one study was registered prospectively.In one study conducted in Australia outcomes were reported only at six months (before participants in the delayed-surgery group had cataract surgery). At six months, the immediate-surgery group showed mean improvement in best-corrected visual acuity (BCVA) compared with the delayed-surgery group (mean difference (MD) -0.15 LogMAR, 95% confidence interval (CI) -0.28 to -0.02; 56 participants; moderate-certainty evidence). In the other study, conducted in Austria, outcomes were reported only at 12 months (12 months after participants in the immediate-surgery group and six months after participants in the delayed-surgery group had cataract surgery). There was uncertainty as to which treatment group had better improvement in distance visual acuity at 12 months (unit of measure not reported; very low-certainty evidence).At 12 months, the mean change from baseline between groups in cumulated drusen or geographic atrophy area size was small and there was uncertainty which, if either, of the groups was favored (MD 0.76, 95% CI -8.49 to 10.00; 49 participants; low-certainty evidence). No participant in one study had exudative AMD develop in the study eye during 12 months of follow-up; in the other study, choroidal neovascularization developed in the study eye of 1 of 27 participants in the immediate-surgery group versus 0 of 29 participants in the delayed-surgery group at six months (risk ratio 3.21, 95% CI 0.14 to 75.68; 56 participants; very low-certainty evidence). Quality of life was measured using two different questionnaires. Scores on the Impact of Vision Impairment (IVI) questionnaire suggested that the immediate-surgery group fared better regarding vision-related quality of life than the delayed-surgery group at six months (MD in IVI logit scores 1.60, 95% CI 0.61 to 2.59; low-certainty evidence). However, we could not analyze scores from the Visual Function-14 (VF-14) questionnaire from the other study due to insufficient data. No postoperative complication was reported from either study.

AUTHORS' CONCLUSIONS

At this time, it is not possible to draw reliable conclusions from the available data as to whether cataract surgery is beneficial or harmful in people with AMD after 12 months. Although cataract surgery provides short-term (six months) improvement in BCVA in eyes with AMD compared with no surgery, it is unclear whether the timing of surgery has an effect on long-term outcomes. Physicians must make recommendations to their AMD patients regarding cataract surgery based on experience and clinical judgment until large controlled trials are conducted and their findings published.There is a need for prospective RCTs in which cataract surgery is compared with no surgery in people with AMD to better evaluate whether cataract surgery is beneficial or harmful in all or a subset of AMD patients. However, ethical considerations preclude withholding surgery, or delaying it for several years, if it may be a potentially beneficial treatment. Designers of future trials are encouraged to utilize existing standardized systems for grading cataract and AMD and for measuring key outcomes: visual acuity, change in visual acuity, worsening of AMD, quality of life measures, and adverse events.

Systemic, Ocular and Genetic Risk Factors for Age-related Macular Degeneration and Polypoidal Choroidal Vasculopathy in Singaporeans

To examine the association of systemic, ocular and genetic risk factors in neovascular age-related macular degeneration (nAMD) in a large cohort of Asian patients, and to further compare risk factors between those with typical AMD and polypoidal choroidal vasculoapthy (PCV) subtypes. We recruited 456 cases and 1,824 controls matched for age, gender and ethnicity. Data on systemic and ocular risk factors were collected on questionnaires. In a subgroup of subjects, we included genetic data on four AMD-associated single nucleotide polymorphisms (SNPs). Risk factors for nAMD and subtypes were analyzed. Systemic risk factors for nAMD included older age, male gender, higher BMI and higher HDL-cholesterol. Ocular risk factors included pseudophakic and shorter axial length. Risk factors common to both typical AMD and PCV subtypes included age, BMI and HDL-cholesterol. Shorter axial length was only associated with PCV, while male gender and pseudophakia were only associated with typical AMD. In the subgroup with genotype data, ARMS2 rs10490924 and CFH rs800292 were associated with nAMD. None of the risk factors were significantly different between PCV and typical AMD. Systemic, ocular and genetic risk factors were largely similar for typical AMD and PCV subtypes in this Asian population based in Singapore.

Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly. AMD is diagnosed based on characteristic retinal findings in individuals older than 50. Early detection and treatment are critical in increasing the likelihood of retaining good and functional vision.

Incidence of Age-Related Macular Degeneration in a Multi-Ethnic United States Population: The Multi-Ethnic Study of Atherosclerosis

PURPOSE

To describe the incidence of age-related macular degeneration (AMD) and associated risk factors in 4 racial/ethnic groups (white, black, Hispanic, and Chinese) residing in the United States.

DESIGN

Prospective cohort study.

PARTICIPANTS

A total of 3811 participants, aged 46 to 86 years, from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort, with retinal data collected twice, on average, 8 years apart.

METHODS

Fundus images, taken using a digital camera through dark-adapted pupils using a standard protocol and the same equipment at both study visits, were graded centrally for early and late AMD on the basis of drusen size, type and area, increased retinal pigment, retinal pigment epithelial depigmentation, neovascular lesions, and geographic atrophy using the modified Wisconsin Age-Related Maculopathy Grading System. Demographic, clinical, and laboratory measures were included in multivariable regression models to determine their impact on the variation in AMD incidence among racial/ethnic groups.

MAIN OUTCOME MEASURES

Incident early and late AMD.

RESULTS

The overall 8-year age- and sex-standardized incidence of early and late AMD were 4.1% and 2.3%, respectively, with incidence of early and late AMD highest in whites (5.3% and 4.1%, respectively), intermediate in Chinese (4.5% and 2.2%, respectively) and Hispanics (3.3% and 0.8%, respectively), and lowest in blacks (1.6% and 0.4%, respectively). By adjusting for age and sex, blacks had a 70% lower risk of developing early AMD than whites, and this decreased only slightly to a 67% lower risk after multivariable adjustment. By adjusting for age, sex, and race/ethnicity, hyperopia was associated with early AMD (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.04-2.20), as was astigmatism (OR, 1.47; 95% CI, 1.00-2.16), but not myopia (P = 0.29). Age, race/ethnicity, current smoking, hyperopia, and AMD-susceptibility genotypes Complement Factor H (CFH) RS1061170 and Age Related Maculopathy Susceptibility 2 (ARMS2) RS3793917 were independently associated with incident early AMD in multivariable models for the combined sample. However, the only statistically significant factor consistently associated with incident early AMD across the 4 racial/ethnic groups was increasing age. Risk factors for late AMD were not assessed because of its low incidence, particularly across racial/ethnic groups.

CONCLUSIONS

Variation in the incidence of early AMD exists among racial/ethnic groups in the United States and is not explained by the clinical, genetic, and environmental factors included in this study.

Matrix γ-carboxyglutamate protein and Fetuin-A, in wet type age-related macular degeneration

AIM

To evaluate the high sensitivity C-reactive protein (hsCRP), Fetuin-A and matrix γ-carboxyglutamate protein (MGP) as the main factors for vascular calcification and inflammation in serum of patients with advanced age-related macular degeneration (ARMD) in comparison to healthy controls.

METHODS

The subjects were 40 patients with choroidal neovascularization (CNV) having a mean age of 70.9±9.1y and a matched group of 49 apparently healthy control subjects. The ARMD was diagnosed using a slit-lamp with superfield lens, fundus photography and fluorescein angiography. Measurement of hsCRP was done by nephelometry method. Levels of Fetuin-A and MGP were measured by enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

hsCRP [0.45(0.07-2.63) mg/L vs 0.25(0.03-1.2) mg/L, P=0.02)] and Fetuin-A levels (50.27±5.04 vs 44.99±10.28 ng/mL, P=0.009) were higher in the patients than in the control groups. We could not find significant difference in MGP level between two groups (P=0.08). There was not a significant correlation between MGP with Fetuin-A and hsCRP among the patients (P=0.7, P=0.9 respectively). A significant negative correlation of hsCRP with Fetuin-A was observed in both case and control groups (P=0.004, r=-0.33 and P=0.001, r=-0.54, respectively).

CONCLUSION

Although our study shows that serum hsCRP and Fetuin-A is increased in CNV patients as well as negatively correlated with both study groups, their direct role on pathogenesis of ARMD required future studies.

Age-Related Macular Degeneration: Advances in Management and Diagnosis

Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in older populations in industrialized nations. AMD is a late-onset deterioration of photoreceptors and retinal pigment epithelium in the central retina caused by various environmental and genetic factors. Great strides in our understanding of AMD pathogenesis have been made in the past several decades, which have translated into revolutionary therapeutic agents in recent years. In this review, we describe the clinical and pathologic features of AMD and present an overview of current diagnosis and treatment strategies.

Current knowledge and trends in age-related macular degeneration: genetics, epidemiology, and prevention

PURPOSE

To address the most dynamic and current issues concerning human genetics, risk factors, pharmacoeconomics, and prevention regarding age-related macular degeneration.

METHODS

An online review of the database Pubmed and Ovid was performed, searching for the key words: age-related macular degeneration, AMD, pharmacoeconomics, risk factors, VEGF, prevention, genetics and their compound phrases. The search was limited to articles published since 1985 to date. All returned articles were carefully screened and their references were manually reviewed for additional relevant data. The webpage www.clinicaltrials.gov was also accessed in search of relevant research trials.

RESULTS

A total of 366 articles were reviewed, including 64 additional articles extracted from the references and 25 webpages and online databases from different institutions. At the end, only 244 references were included in this review.

CONCLUSION

Age-related macular degeneration is a complex multifactorial disease that has an uneven manifestation around the world but with one common denominator, it is increasing and spreading. The economic burden that this disease poses in developed nations will increase in the coming years. Effective preventive therapies need to be developed in the near future.

Is age-related macular degeneration a manifestation of systemic disease? New prospects for early intervention and treatment

Age-related macular degeneration (AMD) is a common vision-threatening condition affecting the elderly. AMD shares common risk factors and processes, including vascular and inflammatory pathways, with many systemic disorders. Associations have been reported between AMD and hypertension, cardiovascular disease, cerebrovascular disease, dyslipidaemia, chronic kidney disease and neurodegenerative disorders. An increasing amount of evidence suggests that individuals with AMD are also at risk of systemic diseases such as stroke. In this review, we summarize the latest evidence to support the notion that AMD is an ocular manifestation of systemic disease processes, and discuss the potential systemic side effects of ocular AMD therapy of which general physicians should be aware. Recent genetic discoveries and understanding of the pathogenic pathways in AMD in relation to systemic disorders are also highlighted.

The prevalence of age-related eye diseases and visual impairment in aging: current estimates

PURPOSE

To examine prevalence of five age-related eye conditions (age-related cataract, AMD, open-angle glaucoma, diabetic retinopathy [DR], and visual impairment) in the United States.

METHODS

Review of published scientific articles and unpublished research findings.

RESULTS

Cataract, AMD, open-angle glaucoma, DR, and visual impairment prevalences are high in four different studies of these conditions, especially in people over 75 years of age. There are disparities among racial/ethnic groups with higher age-specific prevalence of DR, open-angle glaucoma, and visual impairment in Hispanics and blacks compared with whites, higher prevalence of age-related cataract in whites compared with blacks, and higher prevalence of late AMD in whites compared with Hispanics and blacks. The estimates are based on old data and do not reflect recent changes in the distribution of age and race/ethnicity in the United States population. There are no epidemiologic estimates of prevalence for many visually-impairing conditions.

CONCLUSIONS

Ongoing prevalence surveys designed to provide reliable estimates of visual impairment, AMD, age-related cataract, open-angle glaucoma, and DR are needed. It is important to collect objective data on these and other conditions that affect vision and quality of life in order to plan for health care needs and identify areas for further research.

Therapeutic margins in a novel preclinical model of retinitis pigmentosa

The third-most common cause of autosomal recessive retinitis pigmentosa (RP) is due to defective cGMP phosphodiesterase-6 (PDE6). Previous work using viral gene therapy on PDE6-mutant mouse models demonstrated photoreceptors can be rescued if administered before degeneration. However, whether visual function can be rescued after degeneration onset has not been addressed. This is a clinically important question, as newly diagnosed patients exhibit considerable loss of rods and cones in their peripheral retinas. We have generated and characterized a tamoxifen inducible Cre-loxP rescue allele, Pde6b(Stop), which allows us to temporally correct PDE6-deficiency. Whereas untreated mutants exhibit degeneration, activation of Cre-loxP recombination in early embryogenesis produced stable long-term rescue. Reversal at later time-points showed partial long-term or short-lived rescue. Our results suggest stable restoration of retinal function by gene therapy can be achieved if a sufficient number of rods are treated. Because patients are generally diagnosed after extensive loss of rods, the success of clinical trials may depend on identifying patients as early as possible to maximize the number of treatable rods.

Should Posterior Vitrectomy be Made a Priority in Ophthalmic Facilities of Sub Sahara Africa?

BACKGROUND

Posterior vitrectomy facilities are lacking in Sub Sahara Africa due to paucity of trained personnel in vitreo retinal subspecialty. More cases are seen needing vitrectomy, especially cases with vitreous opacities and complications of cataract surgery as more residents are being trained. The review will aim to determine whether vitrectomy facility should be a priority as part of ophthalmic facility in the region.

METHOD

A 3 year review was carried out. All cases of posterior vitrectomy performed at the retinal unit of the University College Hospital, Ibadan, Africa between 2008 and 20011 were retrieved. Indications, and visual outcome were documented. Proportions and percentages were used to analyse the data.

RESULTS

Sixty six posterior vitrectomies were performed during the period. The most common indication for vitrectomy was vitreous hemorrhage n=30 [45.5%].Complication of cataract surgery such as dropped intraocular lens 7 [10.7%], sclera fixated intra ocular lens 6 [9.2%], and dropped nucleus 5 [7.5%] were emerging indications. Other indications noted include complicated retinal detachments 4 (6.1%), membranectomy for posterior capsule opacity from pediatric cataract surgery 3 (4.5%) and congenital lens subluxation 2 (3.0%). Improved visual outcome was noted after surgery. Forty nine [75%] eyes were blind [visual acuity of < 3/60] before vitrectomy. This proportion dropped to 24 [37%] after vitrectomy with an additional 24% regaining navigational vision [visual acuity of 3/60 to Counting fingers at 1meter] .

CONCLUSION

Vitrectomy should be an integral part of eye care and its availability should be made a priority in ophthalmic facilities of Sub Sahara Africa, especially those involved in ophthalmology training.

Dynamic increase in extracellular ATP accelerates photoreceptor cell apoptosis via ligation of P2RX7 in subretinal hemorrhage

Photoreceptor degeneration is the most critical cause of visual impairment in age-related macular degeneration (AMD). In neovascular form of AMD, severe photoreceptor loss develops with subretinal hemorrhage due to choroidal neovascularization (CNV), growth of abnormal blood vessels from choroidal circulation. However, the detailed mechanisms of this process remain elusive. Here we demonstrate that neovascular AMD with subretinal hemorrhage accompanies a significant increase in extracellular ATP, and that extracellular ATP initiates neurodegenerative processes through specific ligation of Purinergic receptor P2X, ligand-gated ion channel, 7 (P2RX7; P2X7 receptor). Increased extracellular ATP levels were found in the vitreous samples of AMD patients with subretinal hemorrhage compared to control vitreous samples. Extravascular blood induced a massive release of ATP and photoreceptor cell apoptosis in co-culture with primary retinal cells. Photoreceptor cell apoptosis accompanied mitochondrial apoptotic pathways, namely activation of caspase-9 and translocation of apoptosis-inducing factor (AIF) from mitochondria to nuclei, as well as TUNEL-detectable DNA fragmentation. These hallmarks of photoreceptor cell apoptosis were prevented by brilliant blue G (BBG), a selective P2RX7 antagonist, which is an approved adjuvant in ocular surgery. Finally, in a mouse model of subretinal hemorrhage, photoreceptor cells degenerated through BBG-inhibitable apoptosis, suggesting that ligation of P2RX7 by extracellular ATP may accelerate photoreceptor cell apoptosis in AMD with subretinal hemorrhage. Our results indicate a novel mechanism that could involve neuronal cell death not only in AMD but also in hemorrhagic disorders in the CNS and encourage the potential application of BBG as a neuroprotective therapy.

Pharmacogenetic influence of LOC387715/HTRA1 on the efficacy of bevacizumab treatment for age-related macular degeneration in a Korean population

PURPOSE

The purpose of this study was to determine the pharmacogenetic effects of complement factor H (CFH) Y402H, LOC387715 and high-temperature requirement factor A1 (HTRA1) genotypes on the treatment of exudative age-related macular degeneration (AMD) by intravitreal bevacizumab injection in a Korean population.

METHODS

Seventy-five patients diagnosed with exudative AMD were treated with intravitreal bevacizumab (2.5 mg) monotherapy. All patients received three initial intravitreal bevacizumab injections every four weeks and were then treated "as needed" based on clinical findings, optical coherence tomography and fluorescein angiography during the 12 month follow-up period after the third injection.

RESULTS

The difference in visual acuity improvement among the three genotypes of LOC387715 were statistically significant at six months post-treatment (logarithm of the minimum angle of resolution; TT, 0.346; GT, 0.264; GG, 0.188; p = 0.037). Among the LOC387715 genotypes, the number of additional injections was lower in patients who had the risk T allele (GG, 2.143; GT, 2.000; TT, 1.575; p = 0.064). There was no significant difference between visual acuity and central macular thickness change in the CFH Y402H polymorphism group during the 12 month follow-up period. However, the TC group of CFH Y402H required more additional bevacizumab injections than the TT group (TT, 1.517; TC, 3.363; p = 0.020).

CONCLUSIONS

This study demonstrated that different LOC387715/HTRA1 genotypes resulted in different bevacizumab treatment responses on exudative AMD. Patients with the risk allele had an improved treatment response and less need for additional injections. However, patients with the CFH Y402H risk allele needed more additional injections of bevacizumab in order to improve visual acuity. This study illustrates how pharmacogenetic factors may help determine treatment modality and dosing. This could ultimately provide basic data for 'personalized medicine' in AMD.

Surgery for cataracts in people with age-related macular degeneration

BACKGROUND

Cataract and age-related macular degeneration (AMD) are common causes of decreased vision that often occur simultaneously in people over age 50. Although cataract surgery is an effective treatment for cataract-induced visual loss, some clinicians suspect that such an intervention may increase the risk of worsening of underlying AMD and thus have deleterious effects on vision.

OBJECTIVES

The objective of this review was to evaluate the effectiveness and safety of cataract surgery in eyes with AMD.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 4), MEDLINE (January 1950 to April 2012), EMBASE (January 1980 to April 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to April 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 16 April 2012.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-randomized trials of eyes affected by both cataract and AMD in which cataract surgery would be compared to no surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the search results against the inclusion and exclusion criteria. Two authors independently extracted data and assessed risk of bias for included studies. We resolved discrepancies by discussion.

MAIN RESULTS

One RCT with 60 participants with visually significant cataract and AMD was included in this review. Participants were randomized to immediate cataract surgery (within two weeks of enrollment) (n = 29) or delayed cataract surgery (six months after enrollment) (n = 31). At six months, four participants were lost to follow-up; two participants from each group. The immediate surgery group showed mean improvement in best-corrected visual acuity (BCVA) compared with the delayed surgery group at six months (mean difference (MD) 0.15 LogMAR, 95% confidence interval (CI) 0.28 to 0.02). There was no significant difference in the development of choroidal neovascularization between groups (1/27 eyes in the immediate surgery group versus 0/29 eyes in the delayed surgery group). Results from Impact of Vision Impairment (IVI) questionnaires suggested that the immediate surgery group faired better with quality of life outcomes than the delayed surgery group (MD in IVI logit scores 1.60, 95% CI 0.61 to 2.59). No postoperative complication was reported. We identified a second potentially relevant study of immediate versus delayed cataract surgery in 54 people with AMD. Results for the study are not yet available, but may be eligible for future updates of this review.

AUTHORS' CONCLUSIONS

At this time, it is not possible to draw reliable conclusions from the available data to determine whether cataract surgery is beneficial or harmful in people with AMD. Physicians will have to make practice decisions based on best clinical judgment until controlled trials are conducted and their findings published.It would be valuable for future research to investigate prospective RCTs comparing cataract surgery to no surgery in patients with AMD to better evaluate whether cataract surgery is beneficial or harmful in this group. However ethical considerations need to be addressed when delaying a potentially beneficial treatment and it may not be feasible to conduct a long-term study where surgery is withheld from the control group. Utilization of pre-existing, standardized systems for grading cataract and AMD and measuring outcomes (visual acuity, change in visual acuity, worsening of AMD and quality of life measures) should be encouraged.

Is age-related macular degeneration a problem in Ibadan, Sub-Saharan Africa?

Background

Age-related macular degeneration (AMD) is considered uncommon in black populations including those of Sub-Saharan Africa. The aim of this review was to determine the pattern of presentation of AMD in our hospital located in Ibadan, the largest city in Sub-Saharan Africa.

Methods

A retrospective review of all cases with AMD presenting to the Eye and Retinal Clinic of the University College Hospital, Ibadan, West Africa was undertaken between October 2007 and September 2010.

Results

In the 3 years reviewed, 768 retinal cases were seen in the hospital, 101 (14%) of which were diagnosed with AMD. The peak age was 60–79 years. The male to female ratio was approximately 2:3. More males presented with the advanced form of dry AMD than females (odds ratio = 2.33). However, more females had advanced wet AMD than males (odds ratio = 1.85). Wet AMD was seen in 40 cases (40%).

Conclusion

The review determined that, as AMD is not uncommon and wet AMD is relatively more common in our hospital than has been reported previously, this is probably true of Ibadan in general.

Causes of blindness and visual impairment in Latin America

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic retinopathy and glaucoma are starting to make serious inroads, although epidemiological data are limited, and age-related macular degeneration is now a concern in some populations. Infectious diseases such as trachoma and onchocerciasis are quickly diminishing. Although progress has been made, retinopathy of prematurity remains the major cause of childhood blindness. If VISION 2020 is to succeed, many more epidemiological studies will be needed to set priorities, although some can be of the Rapid Assessment of Avoidable Blindness design. Developing the infrastructure for screening and treatment of ophthalmic disease in Latin America continues to be a challenge.

Predictive genetic testing for the identification of high-risk groups: a simulation study on the impact of predictive ability

Background

Genetic risk models could potentially be useful in identifying high-risk groups for the prevention of complex diseases. We investigated the performance of this risk stratification strategy by examining epidemiological parameters that impact the predictive ability of risk models.

Methods

We assessed sensitivity, specificity, and positive and negative predictive value for all possible risk thresholds that can define high-risk groups and investigated how these measures depend on the frequency of disease in the population, the frequency of the high-risk group, and the discriminative accuracy of the risk model, as assessed by the area under the receiver-operating characteristic curve (AUC). In a simulation study, we modeled genetic risk scores of 50 genes with equal odds ratios and genotype frequencies, and varied the odds ratios and the disease frequency across scenarios. We also performed a simulation of age-related macular degeneration risk prediction based on published odds ratios and frequencies for six genetic risk variants.

Results

We show that when the frequency of the high-risk group was lower than the disease frequency, positive predictive value increased with the AUC but sensitivity remained low. When the frequency of the high-risk group was higher than the disease frequency, sensitivity was high but positive predictive value remained low. When both frequencies were equal, both positive predictive value and sensitivity increased with increasing AUC, but higher AUC was needed to maximize both measures.

Conclusions

The performance of risk stratification is strongly determined by the frequency of the high-risk group relative to the frequency of disease in the population. The identification of high-risk groups with appreciable combinations of sensitivity and positive predictive value requires higher AUC.

Vitamin D status and early age-related macular degeneration in postmenopausal women

OBJECTIVE

The relationship between serum 25-hydroxyvitamin D (25[OH]D) concentrations (nmol/L) and the prevalence of early age-related macular degeneration (AMD) was investigated in participants of the Carotenoids in Age-Related Eye Disease Study.

METHODS

Stereoscopic fundus photographs, taken from 2001 to 2004, assessed AMD status. Baseline (1994-1998) serum samples were available for 25(OH)D assays in 1313 women with complete ocular and risk factor data. Odds ratios (ORs) and 95% confidence intervals (CIs) for early AMD (n = 241) of 1287 without advanced disease were estimated with logistic regression and adjusted for age, smoking, iris pigmentation, family history of AMD, cardiovascular disease, diabetes, and hormone therapy use.

RESULTS

In multivariate models, no significant relationship was observed between early AMD and 25(OH)D (OR for quintile 5 vs 1, 0.79; 95% CI, 0.50-1.24; P for trend = .47). A significant age interaction (P = .002) suggested selective mortality bias in women aged 75 years and older: serum 25(OH)D was associated with decreased odds of early AMD in women younger than 75 years (n = 968) and increased odds in women aged 75 years or older (n = 319) (OR for quintile 5 vs 1, 0.52; 95% CI, 0.29-0.91; P for trend = .02 and OR, 1.76; 95% CI, 0.77-4.13; P for trend = .05, respectively). Further adjustment for body mass index and recreational physical activity, predictors of 25(OH)D, attenuated the observed association in women younger than 75 years. Additionally, among women younger than 75 years, intake of vitamin D from foods and supplements was related to decreased odds of early AMD in multivariate models; no relationship was observed with self-reported time spent in direct sunlight.

CONCLUSIONS

High serum 25(OH)D concentrations may protect against early AMD in women younger than 75 years.

Prevalence of age-related macular degeneration in a rural Chinese population: the Handan Eye Study

PURPOSE

To describe the prevalence of age-related degeneration (AMD) in a rural Chinese population and to assess its associations with age, gender, and smoking.

DESIGN

Population-based cross-sectional.

PARTICIPANTS

Persons aged 30+ years, recruited between October 2006 and October 2007, from Yongnian County, Handan, Hebei Province, China.

METHODS

All participants underwent a standardized interview and comprehensive eye examinations, including digital retinal photography of both eyes. Trained graders assessed the presence and severity of AMD lesions following the modified Wisconsin Age-related Maculopathy Grading System (WARMGS) used in the Blue Mountains Eye Study (BMES). Direct age standardization to the world population (year 2000) was performed to compare the prevalence across different populations.

MAIN OUTCOME MEASURES

AMD and WARMGS.

RESULTS

Of 6830 participates, fundus photographs were gradable for 6581 persons (96.4%), including 4049 aged 50+ years. Early and late AMD prevalence rates were 3.0% and 0.1%, respectively, among participants. The age-standardized prevalence rates among participants aged 50+ years were 4.7% and 0.2%, respectively. After controlling for age, men had a higher prevalence of early (3.9% vs. 2.3%, odds ratio [OR] 1.7; 95% confidence interval [CI], 1.3-2.2) and late AMD (0.1% vs. 0.03%; OR 3.5; CI, 0.4-33.4) compared with women. Older age (sex-adjusted OR 1.7; CI, 1.3-2.2 per decade of age) and current smoking (age-sex-adjusted OR 1.4; CI, 1.0-2.1) were significantly associated with early AMD prevalence. The proportion of current smokers was substantially higher in men (58.7%) than in women (0.3%). The attributable risk of early AMD from smoking among Chinese men was 24.2%. After controlling for current smoking, the excess prevalence of early AMD in men compared with women reduced by 50% (OR 1.4; 95% CI, 0.9-2.0).

CONCLUSIONS

The prevalence of early AMD in this rural Chinese sample was similar to white persons in the BMES and Asian Malays in the Singapore Malay Eye Study. Late AMD prevalence, however, was lower. Higher prevalence rates for early and late AMD in men compared with women were largely attributed to substantially higher proportions of smokers in rural Chinese men than in women.

Intake of lutein and zeaxanthin differ with age, sex, and ethnicity

Lutein and zeaxanthin are carotenoids that are selectively taken up into the macula of the eye, where they may protect against development of age-related macular degeneration. Accurate assessment of their intakes is important in the understanding of their individual roles in eye health. Current dietary databases lack the appropriate information to ascertain valid dietary intakes of these individual nutrients. The purpose of this research is to determine intakes of lutein and zeaxanthin separately in the National Health and Nutrition Examination Survey (NHANES) 2003-2004. The top major food sources for lutein and zeaxanthin intake in NHANES 2003-2004 were analyzed for lutein and zeaxanthin by high-performance liquid chromatography from June to August 2006. Results were applied to dietary data from 8,525 participants in NHANES 2003-2004. Lutein and zeaxanthin food contents were separated into lutein and zeaxanthin in the nutrient database. Mean intakes from two nonconsecutive 24-hour recalls were grouped into food groups based on nutrient composition; these were matched to the new database, and lutein and zeaxanthin intakes were calculated separately. Among all age groups, both sexes, and all ethnicities, intakes of lutein were greater than of zeaxanthin. Relative intake of zeaxanthin to lutein decreased with age, with zeaxanthin to lutein ratios lower in females. Zeaxanthin to lutein ratios in Mexican Americans was considerably greater than other ethnicities (other Hispanics, non-Hispanic white, non-Hispanic black, other races). Lower zeaxanthin to lutein ratios were measured in groups at risk for age-related macular degeneration (eg, older participants, females). Our findings suggest that the relative intake of lutein and zeaxanthin may be important to age-related macular degeneration risk. Future studies are needed to assess the individual associations of lutein and zeaxanthin in eye health.

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.

Prevalence of early and late age-related macular degeneration in India: the INDEYE study

PURPOSE

To estimate the prevalence of early and late age-related macular degeneration (AMD) in India.

METHODS

Of 7518 people aged 60 years and older identified from randomly sampled villages in North and South India, 5853 (78%) attended an eye examination including fundus photography. Fundus images were graded according to the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

Fundus images were ungradable in 1587 people, mainly because of cataract. People 80 years of age and older were less likely to attend the eye examination and more likely to have ungradable images. For ages 60 to 79 years, the percent prevalence (95% confidence interval [CI]) were late AMD 1.2 (0.8-1.5); and early AMD: grade 1 (soft distinct drusen or pigmentary irregularities), 39.3 (37.2-41.5); grade 2 (soft distinct drusen with pigmentary irregularities or soft indistinct or reticular drusen), 6.7 (5.8-7.6); and grade 3 (soft indistinct or reticular drusen with pigmentary irregularities), 0.2 (0.1-0.4). For ages 80 and older, the respective percent prevalence was: late AMD, 2.5 (0.4-4.7); and early AMD: grade 1, 43.1(35.7-50.6); grade 2, 8.1 (4.3-12.0); and grade 3, 0.5 (0-1.5).

CONCLUSIONS

The prevalence of early AMD (grades 1 and 2) is similar to that observed in Western populations, but grade 3 appears to be lower. The prevalence of late AMD is comparable to that in Western populations in the age group 60 to 79 years. It is likely that the prevalence in the 80 and older age group is underestimated.

The epidemiology of age-related macular degeneration in the Indian subcontinent

CONTEXT

The Indian subcontinent is one of the most populous regions in the world. Given the projected rapid population growth and ageing of the population, age-related macular degeneration (AMD) is likely to emerge as a major public health threat in the near future. However, existing literature on AMD in the region is scarce.

METHODS

This paper reviews the epidemiology and risk factors of AMD in the Indian subcontinent.

RESULTS

Data on AMD in India show prevalences ranging from 1.8% to 4.7%. Blindness prevalence studies in Pakistan, Bangladesh and Nepal have also reported rates of 2.1% to 8.7% for all blindness attributable to AMD. Age-related macular degeneration is therefore a significant cause of visual morbidity in these countries. To date, no reliable epidemiological data on AMD or blindness have been published for Sri Lanka, Afghanistan, Maldives or Bhutan.

CONCLUSIONS

The prevalence of AMD in the region is likely to follow a trend similar to that seen in the developed world in the coming years. Eye care policies should therefore make provisions for this chronic age-related eye disease. In addition, there is an urgent need for more data on the epidemiology of AMD in the Indian subcontinent.

Surgery for cataracts in people with age-related macular degeneration

BACKGROUND

Cataract and age-related macular degeneration (AMD) are significant causes of decreased vision in the elderly that often occur simultaneously. Although cataract surgery is an effective treatment for cataract-induced visual loss, some clinicians suspect that such an intervention may increase the risk of progression of underlying AMD and thus have deleterious effects on vision.

OBJECTIVES

The objective of this review was to evaluate the effectiveness and safety of cataract surgery in eyes with AMD.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library, Issue 4, 2008), MEDLINE (January 1966 to November 2008), EMBASE (January 1980 to November 2008) and Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to November 2008). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 4 November 2008.

SELECTION CRITERIA

We planned to include randomized controlled trials (RCTs) and quasi-randomized trials of eyes affected by both cataract and AMD in which cataract surgery would be compared to no surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the search results against the inclusion and exclusion criteria. Discrepancies were resolved by discussion.

MAIN RESULTS

We found no RCTs, thus no analysis was conducted. Evidence was limited to non-randomized clinical trials and prospective cohort and case-control studies.

AUTHORS' CONCLUSIONS

At this time, it is not possible to draw reliable conclusions from the available data to determine whether cataract surgery is beneficial or harmful in people with AMD. Physicians will have to make practice decisions based on best clinical judgement until controlled trials are conducted and their findings published.

Estimated prevalence and risk factor for age-related maculopathy

PURPOSE

To assess the estimate prevalence and risk factors for age-related maculopathy (ARM) in Seoul, Korea.

PATIENTS AND METHODS

We examined 9,530 subjects with, 40 years of age or older between January 2006 and December 2006 in Seoul, Korea. Subjects underwent fundus photography, clinical examinations (including blood analyses), and completed detailed questionnaires. Fundus images were graded according to definitions from the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

ARM was present in 235 subjects, corresponding to an estimate prevalence of 2.46%. Hepatitis B infection (positive status for HBsAg and HBcAb), serum triglyceride levels and high density lipoprotein levels remained as significant risk factors after age-adjustment. Multivariate analyses showed that the prevalence of ARM was significantly higher in older subjects [odds ratio (OR) 1.134; 95% CI 1.114-1.154] and those who were seropositive for hepatitis B surface antigen (OR 2.566; 95% CI 1.519-4.335).

CONCLUSION

The estimated prevalence of ARM was 2.46%. Age and hepatitis B infection may increase the risk of ARM.

Functional rescue of degenerating photoreceptors in mice homozygous for a hypomorphic cGMP phosphodiesterase 6 b allele (Pde6bH620Q)

PURPOSE

Approximately 8% of autosomal recessive retinitis pigmentosa (RP) cases worldwide are due to defects in rod-specific phosphodiesterase PDE6, a tetramer consisting of catalytic (PDE6alpha and PDE6beta) and two regulatory (PDE6gamma) subunits. In mice homozygous for a nonsense Pde6b(rd1) allele, absence of PDE6 activity is associated with retinal disease similar to humans. Although studied for 80 years, the rapid degeneration Pde6b(rd1) phenotype has limited analyses and therapeutic modeling. Moreover, this model does not represent human RP involving PDE6B missense mutations. In the current study the mouse missense allele, Pde6b(H620Q) was characterized further.

METHODS

Photoreceptor degeneration in Pde6b(H620Q) homozygotes was documented by histochemistry, whereas PDE6beta expression and activity were monitored by immunoblotting and cGMP assays. To measure changes in rod physiology, electroretinograms and intracellular Ca(2+) recording were performed. To test the effectiveness of gene therapy, Opsin::Pde6b lentivirus was subretinally injected into Pde6b(H620Q) homozygotes.

RESULTS

Within 3 weeks of birth, the Pde6b(H620Q) homozygotes displayed relatively normal photoreceptors, but by 7 weeks degeneration was largely complete. Before degeneration, PDE6beta expression and PDE6 activity were reduced. Although light-/dark-adapted total cGMP levels appeared normal, Pde6b(H620Q) homozygotes exhibited depressed rod function and elevated outer segment Ca(2+). Transduction with Opsin::Pde6b lentivirus resulted in histologic and functional rescue of photoreceptors.

CONCLUSIONS

Pde6b(H620Q) homozygous mice exhibit a hypomorphic phenotype with partial PDE6 activity that may result in an increased Ca(2+) to promote photoreceptor death. As degeneration in Pde6b(H620Q) mutants is slower than in Pde6b(rd1) mice and can be suppressed by Pde6b transduction, this Pde6b(H620Q) model may provide an alternate means to explore new treatments of RP.

Possible degradation/biotransformation of lutein in vitro and in vivo: isolation and structural elucidation of lutein metabolites by HPLC and LC-MS (atmospheric pressure chemical ionization)

Metabolites of lutein are highly concentrated in the human macula and are known to provide protection against age-related macular degeneration. The aim of this investigation was to characterize the in vitro oxidation products of lutein obtained through photo-oxidation and to compare them with biologically transformed dietary lutein in intestine, plasma, liver, and eyes of rats. In vivo studies involved feeding rats a diet devoid of lutein for 2 weeks to induce deficiency. Rats were divided into two equal groups (n=6/group) and received either micellar lutein by gavage for 10 days or diet supplemented with fenugreek leaves as a lutein source for 4 weeks. Lutein metabolites/oxidation products obtained from in vivo and in vitro studies were characterized by HPLC and LC-MS (APCI) techniques to elucidate their structure. The characteristic fragmented ions resulting from photo-oxidation of lutein were identified as 523 (M(+)+H(+)-3CH(3)), 476 (M(+)+H(+)-6CH(3)), and 551 (M(+)+H(+)-H(2)O). In the eyes, the fragmented molecules resulting from lutein were 13-Z lutein, 13'-Z lutein, 13-Z zeaxanthin, all-E zeaxanthin, 9-Z lutein, 9'-Z lutein, and 3'-oxolutein. Epoxycarotenoids were identified in liver and plasma, whereas anhydrolutein was identified in intestine. This study emphasizes the essentiality of dietary lutein to maintain its status in the retina.

Role of ocular melanin in ophthalmic physiology and pathology

The mammalian eye consists of several layers of pigmented tissues that contain melanin. The eye is a unique organ for pigment cell research because one can isolate and compare melanosomes from different tissues and embryonic origins. Retinal, iris and ciliary pigment epithelial cells are derived from the neural ectoderm, more specifically from the extremity of the embryonic optical cup, which is also the origin of the retina. In contrast, the pigment-generating cells in the choroid and in the stroma of the iris and ciliary body, uveal melanocytes, are developed from the neural crest, the same origin as the melanocytes in skin and hair. This review examines the potential functions of ocular melanin in the human eye. Following a discussion of the role of melanins in the pigment epithelium and uveal melanocytes, three specific topics are explored in detail-photo-screening protective effects, biophysical and biochemical protective effects, and the biologic and photobiologic effects of the two main classes of melanins (generally found as mixtures in ocular melanosomes)--eumelanin and pheomelanin.

Diet and risk factors for age-related maculopathy

BACKGROUND

Evidence continues to accumulate that oxidative stress is etiologically important in the pathogenesis of age-related maculopathy (ARM) and that appropriate antioxidants of dietary origin may protect against this condition.

OBJECTIVE

Risk factors for ARM may be classed as established or putative. We report a study designed to investigate whether such risk factors are associated with a dietary lack of antioxidants relevant to retinal health.

DESIGN

Dietary, anthropometric, and sociodemographic details relating to 828 healthy Irish subjects aged 20-60 y were recorded in a cross-sectional fashion and analyzed for associations between risk factors for ARM and dietary intake of relevant nutrients.

RESULTS

Of the established risk factors for ARM, increasing age was associated with a relative lack of dietary zeaxanthin (P < 0.05) and tobacco use with a relative lack of dietary vitamin C (P < 0.05). Of the putative risk factors for ARM, alcohol consumption was associated with a relative lack of dietary alpha-linoleic acid (P < 0.05), and female sex was associated with a relative lack of dietary zinc (P < 0.05).

CONCLUSIONS

We showed that several variables related to risk for ARM are associated with a relative dietary lack of key nutrients. Our finding that age, the most important and universal risk factor for ARM, is associated with a relative lack of dietary zeaxanthin, is an important finding that warrants further investigation.

Age-related macular degeneration and recent developments: new hope for old eyes?

Age-related macular degeneration (AMD) is the commonest cause of blindness in the population over 60 years of age and accounts for over 50% of those registered blind in the UK. The incidence is increasing and as older generations live longer a growing number of patients will be affected in the future. Affected patients lose central vision, important in all aspects of everyday life. This review outlines risk factors for AMD, clinical features, treatment and management strategies for patients, families and physicians caring for those with AMD. Recent trials are included along with practical clinical advice. While there is no curative treatment at present, intervention can reduce the risk of developing AMD and limit disease progression if it occurs. These modalities are discussed here. As new discoveries in the field of genetics and novel therapies emerge, a brighter future seems certain for the ageing population.

Bone Mineral Density and Age-Related Maculopathy in Older Women

OBJECTIVES

To determine whether bone mineral density (BMD) is associated with age-related maculopathy (ARM) risk in older women.

DESIGN

Cross-sectional analysis at Year 10 (1997/98) of the Study of Osteoporotic Fractures (SOF).

SETTING

Four clinical centers in the United States.

PARTICIPANTS

One thousand forty-two randomly sampled SOF participants who attended the Year 10 clinic visit.

MEASUREMENTS

ARM status was determined from fundus photographs using a modification of the Wisconsin Age-Related Maculopathy Grading System 6-level severity scale used in the National Health and Nutrition Examination Survey III. Total hip BMD was measured at Year 10 using dual-energy x-ray absorptiometry. Information on potential confounders, including age, reproductive hormone exposures, body mass index, smoking, alcohol consumption, nutrition, education, diabetes mellitus, hypertension, and physical activity, was ascertained with questionnaires.

RESULTS

The prevalence of ARM was 50% (46% had early ARM and 4% had late ARM). After potential confounder adjustment, greater BMD was associated with lower odds of ARM (odds ratio (OR) per 1 standard deviation increase in BMD=0.82, 95% confidence interval (CI)=0.70-0.96). Women in the highest quartile of BMD had lower odds of ARM than those in the lowest quartile (OR=0.63, 95% CI=0.41-0.97) and those in the lowest three quartiles combined (OR=0.66, 95% CI=0.48-0.91).

CONCLUSION

Higher levels of BMD may be associated with lower risk for ARM. The underlying mechanism is unknown, although BMD may be a marker for lifetime endogenous estrogen exposure. Future studies are needed to replicate these findings and further investigate the nature of the relationship between BMD and ARM.

Fifteen-Year Cumulative Incidence of Age-Related Macular Degeneration

PURPOSE

To describe the 15-year cumulative incidence of signs of early and late age-related macular degeneration (AMD).

DESIGN

Population-based cohort study.

PARTICIPANTS

We included 3917 persons, 43 to 86 years of age at the time of a baseline examination in 1988 through 1990 and with information collected in follow-up in 1993 through 1995, and/or 1998 through 2000, and/or 2003 through 2005.

METHODS

Grading of stereoscopic fundus photographs using the Wisconsin Age-Related Maculopathy Grading System.

MAIN OUTCOME MEASURES

Cumulative incidence of drusen type and size, pigmentary abnormalities, geographic atrophy, and exudative AMD accounting for competing risk of death.

RESULTS

The 15-year cumulative incidence was 14.3% for early AMD (the presence of either soft indistinct drusen or the presence of pigmentary abnormalities together with any type of drusen) and 3.1% for late AMD (presence of exudative AMD or geographic atrophy). There was an increased incidence of AMD lesions with age (P<0.05). Individuals > or = 75 years of age at baseline had significantly (P<0.01) higher 15-year incidences of the following characteristics than people 43 to 54 years of age: larger drusen (125 mum in diameter, 24.1% vs 10.6%), soft indistinct drusen (18.7% vs 6.5%), retinal pigmentary abnormalities (20.2% vs 3.7%), exudative macular degeneration (4.4% vs 0.4%), and pure geographic atrophy (3.2% vs 0%). Controlling for age, compared with those with small numbers of only small hard drusen (1-2), those with large numbers of only hard drusen (> or =8) had an increased 15-year age-adjusted incidence of both soft indistinct drusen (16.3% vs 4.7%) and pigmentary abnormalities (10.6% vs 2.7%). Eyes with soft indistinct drusen or pigmentary abnormalities at baseline were more likely to develop late AMD at follow-up than eyes without these lesions (17.8% vs 1.2% and 12.9% vs 1.7%, respectively).

CONCLUSIONS

We document the long-term incidence of signs of AMD and a continuum from small hard drusen to late AMD in older persons in the population. The 15-year cumulative incidence of late AMD in people > or = 75 years of age (8%) indicates a public health problem of significant proportions because the United States population this age is expected to increase by 54% between 2005 and 2025.

Prevalence of age-related maculopathy in the adult population in China: the Beijing eye study

OBJECTIVE

To evaluate the prevalence of age-related maculopathy (ARM) in adult Chinese living in rural or urban regions of mainland China.

DESIGN

Population-based prevalence study.

METHODS

The study included 4439 subjects (aged 40 or more years) out of 5324 subjects invited to participate (response rate 83.4%). It was held in rural and urban regions of Greater Beijing. The participants underwent a detailed ophthalmic examination including fundus photography. All fundus photographs were graded by the Wisconsin Age-Related Maculopathy Grading System.

RESULTS

Fundus photographs were available for 4376 (98.6%) subjects. Early ARM was present in 122 (1.4%) of 8655 (95% confidence interval [CI] 1.16% to 1.66%) eyes or 63 (1.4%) of 4376 (95% CI 1.09% to 1.79%) subjects, late ARM in 12 (0.14%) of 8655 (95% CI 0.06% to 0.22%) eyes or seven (0.2%) of 4376 (95% CI 0.04% to 0.28%) subjects, and exudative ARM as part of late ARM in seven (0.1%) of 8655 (95% CI 0.02% to 0.14%) eyes or six (0.1%) of 4376 (95% CI 0.03% to 0.25%) subjects. The prevalence of early ARM, late ARM, and exudative ARM, respectively, increased from 0.61%, 0.07%, and 0.07% in the 40-to-44-year age group, to 1.66%, 0.26%, and 0.26% in the 55-to-59-year group, and to 2.99%, 0.90%, and 0.60% in the group aged 75 years and older. ARM was causative for visual impairment (best-corrected visual acuity in the better eye, <20/60 and > or =20/400) or blindness (visual acuity <20/400) in one subject (0.023%).

CONCLUSIONS

Visual impairment due to ARM was relatively uncommon in the adult Chinese population in rural and urban regions.