Macular Degeneration: West SK

Muñoz B, West SK. · Dana Center, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA. · Br J Ophthalmol. · Pubmed #11973241 links to  free full text

Abstract: AIM: To summarise available data on the prevalence and causes of visual impairment and blindness in the Americas and the Caribbean. METHODS: The published literature was searched in Medline and LILACS using the following key words: blindness, visual impairment, prevalence. Articles were reviewed, and the references of the articles were also searched for relevant articles, which were also reviewed. RESULTS: Using the mortality in children under the age of 5 as an indicator, the overall prevalence of childhood blindness (in the under age 15 group) for the region was estimated at 0.45/1000, with the majority (67%) living in countries with mortality of children under age 5 above 30/1000 live births. Corneal opacities were more common in countries where the under 5 year mortality are above 30/1000 live births and retinopathy of prematurity (ROP) was an important cause in countries with intermediate death rates. For adults, overall blindness rates were not estimated because of the social, economic, and ethnic diversity in the region. The primary causes of visual loss in adults in the Americas were age related eye diseases, notably cataract and glaucoma in the African-American and Hispanic populations, and age related macular degeneration in the white population. Uncorrected refractive error was a significant cause of decreased vision across ages, ethnic groups, and countries. CONCLUSION: More data are needed on the magnitude and causes of visual loss for the Caribbean and Latin American countries. Rates of blindness and visual loss from available data within these countries are widely disparate. Prevention and control of avoidable blindness needs to be an ongoing focus in this region.

Hawkins BS, Bird A, Klein R, West SK. · The Wilmer Ophthalmological Institute, Baltimore, MD 21205-2010, USA. · Mol Vis. · Pubmed #10562650 links to  free full text

Abstract: For more than two decades, researchers have sought to identify "risk factors" for age-related macular degeneration (AMD), a major cause of irreversible vision loss in the Western world, particularly in the elderly. Two issues have complicated this search: failure to differentiate between different stages of AMD and misinterpretation of measures of association (odds ratios) and risk (risk ratios) derivable from different research designs. Fortunately, in more recent epidemiologic studies, more attention has been given to these issues. Three groups of potential "risk factors" that have been studied were reviewed: those known to be risk factors for cardiovascular disease, environmental factors, and racial and ethnic factors. Of these, only tobacco smoking, a known risk factor for cardiovascular disease, has been demonstrated to be associated with AMD consistently across many studies of different design, carried out within different populations. The available evidence supports at least a doubling of risk of late AMD associated with long-term smoking, a factor that is under the control of the individual. The preponderance of evidence has not supported other factors to the same degree. Presently, racial and ethnic factors are high priorities for further research.

Friedman DS, West SK, Munoz B, Park W, Deremeik J, Massof R, Frick K, Broman A, McGill W, Gilbert D, German P. · Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins Medical Institutions, Baltimore, MD 21287, USA. · Arch Ophthalmol. · Pubmed #15249367 No free full text.

Abstract: OBJECTIVE: To determine the prevalence and causes of low vision in a large sample of nursing home residents. METHODS: Twenty-eight nursing homes on the Eastern Shore of Maryland and Delaware were enrolled in a clinical trial to assess the impact of vision restoration/rehabilitation on nursing home residents. Visual acuity was measured using both recognition charts and preferential looking techniques. An ophthalmologist examined all residents with visual acuity worse than 20/40 in the better-seeing eye and determined the primary cause for decreased vision. Results are reported for the better-seeing eye. RESULTS: Of 2544 eligible residents, 1591 (63%) participated, but 286 residents were unable to respond to visual acuity testing. Of the remaining 1307 residents, 496 (37%) had best-corrected visual acuity worse than 20/40 in the better-seeing eye. Causes were ascribed for 412 subjects. Rates of low vision were similar between African American subjects and white subjects (39% and 38%, respectively; age-adjusted P =.18). Cataract was the leading cause of low vision, responsible for 37% of low vision among white subjects and 54% of low vision among African American subjects. Macular degeneration was responsible for 29% of low vision among white subjects but only 7% among African American subjects. Glaucoma caused low vision in 4% of white subjects and 10% of African American subjects. Refractive error was not a frequent cause of low vision in nursing home residents. CONCLUSIONS: Low vision is highly prevalent among nursing home residents, with 37% having visual acuity worse than 20/40 in the better-seeing eye. Differences in causes of low vision between African American subjects and white subjects were noted, with African American subjects more likely to have vision loss on the basis of cataract, a readily treated condition. Appropriate interventions for nursing home residents, who face significant obstacles in accessing eye care services, have the potential to improve the quality of life of this at-risk older population.

Muñoz B, West SK, Rubin GS, Schein OD, Quigley HA, Bressler SB, Bandeen-Roche K. · Wilmer Eye Institute, The Johns Hopkins University, 600 N Wolfe St, Room 116, Baltimore, MD 21287, USA. · Arch Ophthalmol. · Pubmed #10865321 No free full text.

Abstract: OBJECTIVE: To determine the causes of blindness and visual impairment in a population-based sample of older Americans. METHODS: A random sample of 3821 residents of Salisbury, Md, between the ages of 65 and 84 years was identified from Medicare records. Sixty-six percent (2520 persons) agreed to undergo an eye examination; 26% of the participants were African American. The clinical examination included acuity testing with an Early Treatment Diabetic Retinopathy Study chart and standardized refraction testing for those with a visual acuity worse than 20/30, slitlamp and dilated retinal examination by an ophthalmologist, tonometry, lens and fundus photography, and a suprathreshold visual field test. Visual impairment was defined as a best-corrected acuity in the better-seeing eye worse than 20/40 and better than 20/200, while blindness was acuity in the better-seeing eye of 20/200 or worse. For those with a visual acuity worse than 20/40 in either eye, one or more causes were assigned by an ophthalmologist and a final cause for each eye was confirmed by a panel of 3 subspecialty ophthalmologists (O.D.S., H.A.Q., and S.B.B.) based on all available evidence. RESULTS: Bilateral presenting acuity worse than 20/40 increased from 4% in the 65- to 74-year age group to 16% in the 80- to 84-year age group. One third of those with presenting acuity worse than 20/40 improved to 20/40 or better with refraction. Overall, 4.5% had a best-corrected acuity worse than 20/40. African Americans were more likely to remain visually impaired than were whites despite refraction (odds ratio [95% confidence interval], 1.7 [1.1-2.6]). Whites were most often impaired or blind from age-related macular degeneration (1.2% vs 0.5%; P=.09). African Americans had higher rates of impairment and blindness from cataract or posterior capsular opacification (2.7% vs 1.1%; P=.006), glaucoma (0.9% vs 0.1%; P=.006), and diabetic retinopathy (1.2% vs 0.2%; P=. 004). CONCLUSIONS: More than half of those with visual impairment or blindness had conditions that were either surgically treatable or potentially preventable. African Americans had a disproportionate number of blinding diseases, particularly those amenable to eye care intervention. Targeted interventions for specific populations to increase appropriate eye care use would greatly improve vision and function in older Americans. Arch Ophthalmol. 2000;118:819-825

Bressler SB, Muñoz B, Solomon SD, West SK, Anonymous00118. · The Wilmer Eye Institute, Johns Hopkins Hospital, 600 N Wolfe St, Baltimore, MD 21287-9228, USA. · Arch Ophthalmol. · Pubmed #18268216 links to  free full text

Abstract: OBJECTIVE: To determine differences in the prevalence of age-related macular degeneration (AMD) and its fundus manifestations in a population-based sample of older black and white Americans. DESIGN: Cross-sectional population-based study of 2520 participants of whom 1854 are white and 666 are black. Mean age was 73.5 years. Stereoscopic color fundus photographs were graded for presence, severity, and location of drusen, retinal pigment epithelium abnormalities, and choroidal neovascularization or disciform scarring. RESULTS: Drusen at least 64 microm in size were identified in 56% of black and white individuals within 3000 microm of the foveal center, but drusen larger than 125 microm were more common among white participants (16% white vs 11% black individuals). Drusen at least 250 microm in size, confluent drusen, or a larger area (> 10%) occupied by drusen were each more common among white participants. White individuals were 3 times more likely to have focal hyperpigmentation than black individuals. Racial differences were most pronounced for features within the central 1500-microm macular zone. Neovascular AMD was present in 1.7% of white participants and 1.1% of black participants (age-adjusted, P = .38), whereas geographic atrophy was more common in white than black individuals (1.8% vs 0.3%; age-adjusted, P = .02). CONCLUSIONS: White persons are generally more likely than black persons to have medium or large drusen, focal pigment abnormalities, and advanced AMD. Racial differences were prominent for nonneovascular AMD features only when present in the central zone. These data suggest that black individuals may have a mechanism for protection in the central zone against these critical fundus features, which themselves convey high risk of progression to advanced AMD.

Chang MA, Bressler SB, Munoz B, West SK. · Retina Division and Dana Center for Preventative Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA. · Invest Ophthalmol Vis Sci. · Pubmed #18263809 links to  free full text

Abstract: PURPOSE: To evaluate risk factors for the incidence and progression of age-related macular degeneration (AMD) in a racially heterogeneous, geriatric population. METHODS: Subjects (n = 2240) aged 65 to 84 years underwent 2 examinations separated by 2 years, of which 1937 subjects (85%) were included in this report. Fundus photographs were performed at each examination and were graded by trained readers. Multivariate logistic regression models adjusted for age, sex, race, and clustering between eyes were used to evaluate risk factors for AMD incidence and progression. RESULTS: Smoking was a strong, dose-dependent, risk factor for progression from medium size drusen to large drusen or pigmentary abnormalities within the central 1500-microm macular zone. Smoking was also a strong risk factor for development of incident focal pigmentation within 3000 microm of the foveal center. White participants were significantly more likely than blacks to develop large drusen and focal pigmentation and to progress from medium- to large-sized drusen or pigment abnormalities within the central 1500 microm macular zone. However, whites did not have an increased risk of progression from large drusen or pigment abnormalities within the central 1500-microm perimacular zone to foveal GA or CNV when compared with blacks. CONCLUSIONS: Smoking and race are important risk factors for progression from medium to large drusen or to pigment abnormalities within the central 1500-microm macular zone. Limitations in the power of this study preclude assessment of the roles of smoking and race on the ultimate progression to foveal GA or CNV once central large drusen or pigment abnormalities are present.

Grassi MA, Fingert JH, Scheetz TE, Roos BR, Ritch R, West SK, Kawase K, Shire AM, Mullins RF, Stone EM. · Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City 52242, USA. · Hum Mutat. · Pubmed #16865697 No free full text.

Abstract: Age-related macular degeneration (AMD) is the most common cause of irreversible visual loss in the developed world. Previous studies have demonstrated that the c.1204T>C, p.Tyr402His allelic variant in the complement factor H (CFH) gene is associated with an approximately three-fold increased risk for AMD in Caucasians of predominantly European descent. Both the prevalence as well as the phenotypic spectrum of AMD varies widely among persons of different ethnicities. We hypothesized that populations with a lower prevalence of AMD might also have a lower prevalence of the CFH risk allele. In this study we sought to determine the frequency of this sequence variant in control populations of Caucasians, African Americans, Hispanics, Somalis, and Japanese. Normal control populations were assembled for each ethnic group: Caucasian (n=148), Somali (n=128), African American (n=75), Hispanic (n=81), and Japanese (n=82). Individuals were genotyped using a restriction digest assay and the frequency of the C allele at nucleotide position 1204 of the CFH gene was determined. A bioinformatic approach was used to identify SNPs in linkage disequilibrium with rs1061170 (c.1204T>C, p.Tyr402His) from the human haplotype map project database (HapMap) in order to validate the findings. We found widely discordant frequencies of the risk allele between some of the different ethnic groups: Japanese 0.07+/-0.02, Hispanics 0.17+/-0.03, African-Americans 0.35+/-0.04, Caucasians 0.34+/-0.03, and Somalis 0.34+/-0.03. Allele frequencies generated by analysis of the HapMap database were consistent with these findings. This study suggests that there are other yet unidentified genetic factors important in the pathogenesis of AMD that may mitigate the effects of c.1204T>C, p.Tyr402His variant.

Muñoz B, Klein R, Rodriguez J, Snyder R, West SK. · Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA. · Arch Ophthalmol. · Pubmed #16286621 No free full text.

Abstract: OBJECTIVE: To report the prevalence of age-related macular degeneration (AMD) in a population-based sample of Hispanic individuals aged 50 years and older. METHODS: Proyecto VER (Vision and Eye Research) is a population-based study of blindness and visual impairment of Hispanic people in Arizona. Participants underwent complete ophthalmic evaluation, including stereoscopic fundus photography of fields 1, 2, and 4. All photographs for participants aged 50 years and older were graded using the Wisconsin Age-Related Maculopathy Grading system. The following signs were graded: drusen size, drusen type, and the area covered by drusen; pigmentary abnormalities; geographic atrophy; and exudative AMD. RESULTS: Sixty-seven percent (3178) of the original 4774 participants were 50 years of age or older. Of those, 92% (2928) had fundus photographs in at least 1 eye, and 95% (2780) of the photographs were of sufficient quality to grade early and late AMD. OUTCOME MEASURES: The overall prevalence of late AMD was 0.5%. The prevalence increased from 0.1% in the 50- to 59-year age group to 4.3% in the group aged 80 years and older. Likewise, early AMD was strongly associated with age with a prevalence of 20% in the 50- to 59-year age group, increasing to 54% in the group aged 80 years and older. The prevalence of early AMD in Hispanic people was significantly higher than the reported prevalence in the white population. However, the prevalence of late AMD was lower than the estimates for the white population of the United States. CONCLUSIONS: Although early macular changes were very common among Hispanic people, the prevalence of late AMD was infrequent. Further work is necessary to understand the underlying reasons for the different patterns of presentation of early and late signs of AMD among racial/ethnic groups and to characterize early AMD based on predictive value for severe disease in different populations.

Freeman EE, Muñoz B, Bressler SB, West SK. · Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD 21287, USA. · Ophthalmic Epidemiol. · Pubmed #15848919 No free full text.

Abstract: PURPOSE: To evaluate a potential relationship between hormone replacement therapy (HRT), reproductive factors and age-related macular degeneration (AMD). METHODS: 1,458 female participants (age 65-84) from the Salisbury Eye Evaluation study were available for this cross-sectional analysis. AMD outcomes were identified by reading center assessment of fundus photographs. RESULTS: Women who currently used HRT had a lower adjusted odds of large drusen (> 125 microm) (OR = 0.5, 95% CI 0.2-1.0). Use of HRT was not statistically significantly associated with the prevalence of early AMD or advanced AMD, although the odds ratios were all much less than 1. Women who had had an increased number of births had a greater prevalence of large drusen (test of linear trend, p = 0.03). CONCLUSIONS: Current use of HRT was associated with a lower odds of large drusen, which may be predictive of advanced AMD. No statistically significant correlations were found between HRT or reproductive factors and early or advanced AMD.

Freeman EE, Munoz B, West SK, Tielsch JM, Schein OD. · Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9019, USA. · Am J Ophthalmol. · Pubmed #12788126 No free full text.

Abstract: PURPOSE: To determine whether cataract surgery is associated with an increased prevalence of age-related macular degeneration (AMD) in three independent population-based data sets. DESIGN: Cross-sectional study. METHOD: Data were used from the Salisbury Eye Evaluation (2,520 subjects from Salisbury, Maryland, aged 65 to 84 years), the Proyecto VER (4,774 Hispanic subjects from Arizona aged 40 years and older), and the Baltimore Eye Survey (4,396 subjects from Baltimore, Maryland, aged 40 and older). The main outcome measure was AMD as determined by retinal photographs or clinical examination. RESULTS: A history of cataract surgery was associated with an increased prevalence of late AMD in all three data sets after adjusting for age, race, sex, and smoking, but odds ratios (OR) were not individually statistically significant. The OR for the combined analysis was 1.7 (95% confidence interval: 1.1-2.6). Having a severe cataract in the eye was also associated with a slightly higher prevalence of late AMD, although the combined OR was not statistically significant (OR = 1.4; 95% confidence interval, 0.8%-2.4). Overall, increasing time since cataract surgery was not associated with late AMD. CONCLUSIONS: A history of cataract surgery may be associated with an increased prevalence of late AMD. However, having a severe cataract in the eye may also be associated with a higher prevalence of late AMD. Additional research is needed to investigate whether a causal relationship exists between cataract surgery and AMD or whether this relationship is due to residual confounding or bias.

Rodriguez J, Sanchez R, Munoz B, West SK, Broman A, Snyder RW, Klein R, Quigley H. · Department of Ophthalmology, University of Arizona, Tucson, AZ, USA. · Ophthalmology. · Pubmed #11927431 No free full text.

Abstract: OBJECTIVE: To describe the causes of blindness and visual impairment in a population-based sample of Hispanics. DESIGN: A cross-sectional study. PARTICIPANTS: A random sample of 4774 Hispanic residents of Santa Cruz and Pima Counties in Southern Arizona aged 40 years and older who participated in Proyecto VER (Vision Evaluation and Research). TESTING: Subjects were interviewed and underwent a thorough ophthalmic examination. Presenting and best-corrected visual acuity was determined using the Early Treatment of Diabetic Retinopathy Study protocol, followed by a standardized ophthalmic examination to determine the causes of visual loss. Anterior and posterior segment specialists in ophthalmology confirmed the causes. MAIN OUTCOME MEASURES: Causes of visual loss (best-corrected acuity worse than 20/40). RESULTS: The response rate of eligible participants was more than 70%. Best-corrected acuity in the better seeing eye worse than 20/40 increased from 0.3% in those aged 40 to 49 to 5.6% in those aged 65 and older. The leading cause was cataract, accounting for 42% of all visual loss, followed by age-related macular degeneration (15%), and diabetic retinopathy (13%). Among 14 people who were bilaterally blind, open-angle glaucoma was the leading cause. Women had higher age-adjusted prevalence of severe cataract compared with men and were more likely to be visually impaired from cataract, diabetic retinopathy, and open-angle glaucoma, although gender differences were not statistically significant. CONCLUSIONS: Causes of visual impairment differ from those reported in Caucasian populations, with open-angle glaucoma being the leading cause of blindness. Further work on gender-based obstacles to eye care in the Hispanic community may be warranted.