Frequency and risk factors for pterygium in the Barbados Eye Study

OBJECTIVE: To describe the disrtibution and risk factors for pterygium in the predominantly black population of the Barbados Eye Study, which was based on a random sample for Barbadian-born citizens between the ages of 40 and 84 years. METHODS: The standardized protocol included ophtalmic and other measurements, automated perimetry, lens gradings, fundus photography, and a detailed interview. A 10 percent systematic sample of participants and those meeting specific criteria also received a comprehensive ophthalmologic evaluation. RESULTS: The Barbados Eye Study included 4709 participants, of whom 2978 were referred for an ophthalmologic evaluation and 2781 (93 percent) completed the examination. Cases of pterygium were found among 23.4 percent of 2617 black, 23.7 percent of 97 mixed (black and white), and 10.2 percent of 59 white participants examined. In addition to African ancestry, logistic regression analyses indicated a positive association between pterygium and age (odds ratio [OR], 1.01; 95 percent confidence interval [CI], 1.00-1.02), fewer years of education (OR, 1.43; 95 percent CI, 1.01-2.03), and an outdoor job location (OR, 1.87; 95 percent CI, 1.52-2.29). Having a darker skin complexion (OR, 0.66; 95 percent CI, 0.52-0.83), always using sunglasses outdoors (OR, 0.18; 95 percent CI, 0.06-0.59), and the use of prescription glasses (OR, 0.75; 95 percent CI, 0.60-0.93) were protective factors. CONCLUSIONS: Approximately one quarter of the black participants examined had pterygia, a frequency that was 2.5 to 3 times higher than among whites in the Barbados Eye Study and elsewhere. Pterygium was almost twice as frequent among persons who worked outdoors but only one fifth as likely among those who always used sun glasses outdoors. Educational interventions to modify these potential exposures may assist in preventing pterygium. (AU)

Observed versus indirect estimates of incidence of open-angle Glaucoma

Incidence data on open-angle glaucoma (OAG) are limited and difficult to obtain. To date, few studies have reported incidence directly measured from population-based cohorts. Other reported estimates have been derived indirectly from age-specific prevalence by using several assumptions, and their validity is unknown. To the authors' knowledge, this report presents the first comparison of observed versus indirect estimates of OAG incidence based on data from the population-based Barbados Incidence Study of Eye Diseases (1992-1997) (n= 3,427; 85 percent participation). The observed 4-year incidence of OAG was 1.2 percent (95 percent confidence interval (CI):ages 60-69 years, and 4.2 percent (95 percent CI: 2.6, 6.3 percent) in persons at ages 70 or more years. When incidence was calculated from the prevalence data, power function fitting achieved a closer approximation to observed incidence than did logistic curve fitting. Calculated incidence rate for each group were similar when assuming mortality that was equal (incidence rate= 0.7, 1.3, 2.3, and 4.8 percent) or differential (incidence rate= 0.7, 1.2, 2.4, and 4.8 percent). Other nonlogistic approaches also increased the resemblance of observed and calculated estimates. The absence of longitudinal data, reasonably valid incidence estimates of OAG were obtained from available prevalence data. These estimation techniques can be useful when OAG incidence estimates are required for research or public health purposes. (AU)

Incidence of open-angle glaucoma. The Barbados Eye studies

OBJECTIVE: To measure the 4-year risk of open-angle glaucoma (OAG) in a black population. DESIGN: Population-based cohort study with 4 years of follow up. SETTING: Simple random sample of residents of Barbados, West Indies, aged 40 years or older. PARTICIPANTS: A total of 3427 members of the cohort (85 percent of those eligible). MAIN OUTCOME MEASURE: Development of glaucoma visual field defects and optic disc damage, confirmed by automated perimetry, independent fundus photographic gradings, and standardized opthalmologic examinations. RESULTS: The 4-year risk of OAG in black participants was 2.2 percent (95 percent confidence interval, 1.7 percent-2.8 percent), based on 67 newly developed cases of OAG. Incidence rates increased from 1.2 percent at ages 40 to 49 years to 4.2 percent at ages of 70 years or more, tending to be higher in men than women (2.7 percent vs 1.9 percent). About half of the incident cases were undiagnosed previously, and the rest were receiving OAG treatment. Of the 67 new cases of OAG, 32 had intraocular pressure of 21 mm HG or less at baseline (1.2 percent incidence) and 35 had higher pressures (9 percent incidence). Risk was the highest among persons classified as having suspect OAG at baseline (26.1 percent), followed by those with ocular hypertension (4.9 percent and lowest in the remining population (0.8 percent). CONCLUSIONS: This longitudinal study provides new information on OAG risk, as well as the first incidence measurement in a black population. Although intraocular pressure increased risk, about half of the new cases had baseline pressures of 21 mm Hg or less. Results substantiate the high OAG risk in the population of African origin, especially in older adults; the relative role of intraocular pressure; and the considerable underdetecion of new disease after 4 years of follow-up. (AU)

Longitudinal changes in IOP and incident glaucoma in the Barbados Eye Studies

PURPOSE: There are a few longitudinal population studies describing the progression of intraocular pressure (IOP) or the risk of developing incident open-angle glaucoma (OAG). This report examines changes in IOP and measures the incidence of IOG over a 4-year period in the population of the Barbados Eye Studies. METHODS: The Barbados Incidence Study of Eye Disease (BISED) re-examined members of the Barbados Eye Study (BES) cohort, the original sample being based on a simple random sample of the country's population aged 40 - 84 years. At both visits patients had applanation tonometry, automated Humphrey perimetry, a comprehensive opthalmological examination, colour stereo fundus photography, blood pressure and anthropometric measurements and a detailed interview. RESULTS: A total of 3427 participants or 85 percent of the eligible cohort were re-examined in BISED. The IOP analyses were based on the subset of 2640 Black participants without glaucoma (OAG, or other type) or history of IOP lowering treatment at either visit. The mean age at follow-up was 55 years and 60 percent were women. Mean IOP was 17.3 mmHg (SDñ3.0, median 17.0) at baseline and increased by 2.6 mmHg (SDñ3.6 mmHg, median 2.3)(p<0.001by paired 1 test) in 4 years. Factors positively associated with longitudinal increases in IOP include age (p=0.001) and baseline hypertension (p=0.014) or high systolic blood pressure(p=0.005), while there was an inverse association with baseline IOP. Among the 2989 Black participants without OAG at baseline,the 4-year incidence of OAG was 2.2 percent (95 percent CI: 1.7 percent, 2.8 percent). Incidence was highest among persons classified as suspect OAG at baseline (26.1 percent) followed by ocular hypertensives with IOP >21 mmHg (4.9 percent) and lowest in persons with normal / other diagnoses and with IOP ó21 mmHg (0.8 percent). However, 32 of the 67 new cases of OAG (48 percent) had IOP ó21 at baseline. CONCLUSION: Significant increases in IOP were seen at 4-year follow-up in persons without glaucoma or IOP-lowering treatment history. While high IOP increases the risk of OAG, almost half of the incident cases had IOPó21mmHg at baseline. These results highlight the importance of prognostic factors, other than IOP, in determining the development of OAG.(AU)

Cataract and mortality in an Afro-Caribbean population: the Barbados eye studies

OBJECTIVE: Age related cataract is the major cause of visual impairment globally, and is more prevalent in black than white populations. Several studies have shown associations between cataract and mortality, and this report aimed to examine whether lens opacities were associated with mortality in an Afro-Caribbean population. DESIGN AND METHODS: The Barbados Incidence Study of Eye Disease (BISED) re-examined the Barbados Eye Study (BES) cohort, which was based on a simple random sample of Barbadian-born citizens, age 40 to 84 years. Eighty-five percent of those eligible (3,427 participants) has a 4-year follow-up visit. Both visits included an interview, anthropometric measurements, and a detailed ophthalmologic examination, including lens grading with the LOCS II method. Mortality was verified from records held at the Ministry of Health. RESULTS: Cardiovascular disease was the principal cause of death (3.7 percent), followed by malignant neoplasms (1.4 percent). Cumulative 4-year mortality increased from 3.1 percent among those without cataract to 6.0 percent, 8.9 percent and 19.6 percent for cortical-only, nuclear-only and mixed cataract, respectively. An independent association was demonstrated between mixed opacities and 4-year mortality (death rate ratio: 1.6). Co-existing diabetes acted as an effect modifier, increasing mortality in those with mixed lens opacities. The presence of any nuclear cataract (death rate ratio 1.5) was also associated with an increase risk of death. CONCLUSION: This study is the first to confirm an association between cataract and mortality in a population of African descent.(AU)

Diabetic retinopathy in a black population: the Barbados Eye Study

OBJECTIVE: The distribution of diabetic retinopathy in black populations is largely unknown. The authors present retinopathy data from the predominantly black participants of the Barbados Eye Study (BES). DESIGN AND PARTICIPANTS: Prevalence study of 4631 participants based on a random sample of the Barbados population 40 to 84 years of age (84 percent participation). MAIN OUTCOME MEASURES: Diabetes was defined as self-reported history of physician-diagnosed diabetes or glycosylated hemoglobin greater than 10 percent (>2 standard deviations above the population mean of persons without a diabetes history). Retinopathy was assessed by independent grading of 30 degrees color stereo fundus photographs of the disc and macula. RESULTS: Diabetes was present in 19.4 percent of black (n = 4314), 15.2 percent of mixed (black and white, n = 184), and 7.5 percent of white/other (n = 133) self-reported racial groups. In the black/mixed population, regardless of diabetes status, the prevalence of retinopathy was 5.9 percent. In the 636 black and mixed participants with diabetes, the prevalence of retinopathy was 28.5 percent: 19.8 percent had minimum changes, 7.7 percent had moderate changes, and 0.9 percent had severe retinopathy. Clinically significant macular edema (CSME) was found in 8.6 percent of those with diabetes. CONCLUSIONS: In the population of African origin, approximately 1 in 17 persons had retinopathy. Among those with diabetes, 28.5 percent had retinopathy and 8.6 percent had CSME. These results highlight the clinical and public health relevance of diabetic retinopathy in the black populaion.(AU)

Refractive errors in a black adult population: the Barbados Eye Study

PURPOSE: To describe the prevalence of refractive errors in a black adult population. METHODS: The Barbados Eye Study, a population-based study, included 4709 Barbados-born citizens, or 84 percent of a random sample, 40 to 84 years of age. Myopia and Hyperopia were defined as a spherical equivalent <-0.5 diopters and >+0.5 diopters, respectively, based on automated refraction. Analyses included 4036 black participants without history of cataract surgery. Associations with myopia and hyperopia were evaluated in logistic regression analyses. RESULTS: The prevalence of myopia was 21.9 percent and was higher in men (25.0 percent) than in women (19.5 percent). The prevalence of hyperopia was 46.9 percent and was higher in women (51.8 percent) than in men (40.5 percent). The prevalence of myopia decreased from 17 percent in persons 40 to 49 years of age to 11 percent in those 50 to 59 years of age, but increased after 60 years of age. The prevalence of hyperopia increased from 29 percent at 40 to 49 years of age to 65 percent at 50 to 59 years of age, and tended to decline thereafter. A higher prevalence of myopia was positively associated (P < 0.05) with lifetime occupations requiring nearwork, nuclear opacities, posterior subcapsular opacities, glaucoma, and ocular hypertension. Factors associated with hyperopia were the same as for myopia, except for occupation, and in the opposite direction. CONCLUSION: High prevalences of myopia and hyperopia were found in this large black adult population. The prevalence of myopia (hyperopia) increased (decreased) after 60 years of age, which is inconsistent with data from other studies. The high prevalence of age-related cataract, glaucoma, and other eye conditions in the Barbados Eye Study population may contribute to the findings.(AU)

Diabetic retinopathy in Barbados: the Barbados eye study

OBJECTIVE: Diabetic retinopathy is an important cause of visual loss in Barbados and the Caribbean region. The Barbados Eye Study (BES) provides the largest source of population based data on diabetic retinopathy in black adults. METHODS: This is a prevalence study of 4,631 participants based on a random sample of the Barbados population aged 40-84 years (84 percent participation). Diabetes was defined as self-reported history of physician diagnosed diabetes and/or glycosylated haemoglobin > 10 percent (2 standard deviations above the population mean of persons without a diabetes history). Retinopathy was assessed by independent gradings of 30 degrees colour stereo fundus photographs of the disk and macula. RESULTS: Diabetes was present in 19.4 percent of blacks (n=4,313), 15.2 percent of mixed black and white; n=184), and 7.5 percent of white/other (n=133) self reported racial groups. Type 1 diabetes was infrequent. In the overall black/mixed study population regardless of diabetes status, the prevalence of retinopathy was 5.9 percent. In the 636 black and mixed participants with diabetes and gradable fundus photographs, the prevalence of retinopathy was 28.5 percent; 19.8 percent had minimum background changes, 7.7 percent had moderate changes and 0.9 percent had severe retinopathy. Clinically significant macular oedema (CSME) was found in 8.6 percent of those with diabetes. CONCLUSION: In the Afro-Caribbean population over 40 years of age, about 1 in 17 persons had retinopathy. Among those with diabetes, 28.5 percent had retinopathy and 8.6 percent had CSME. These results highlight the clinical and public health relevance of diabetic retinopathy in the region (AU)

Diabetes, hypertension, and central obesity as cataract risk factors in a black population. The Barbados Eye Study

OBJECTIVE: The increased cataract prevalence of black populations, especially of cortical cataract, remains unexplained. The authors evaluate the relationships of diabetes, hypertension, and obesity patterns to lens opacities, by age, among 4314 black participants in the Barbados Eye Study. DESIGN AND PARTICIPANTS: Prevalence study of a random sample of the Barbados population, ages 40 to 84 years (84 percent participation). MAIN OUTCOME MEASURES: Associations with age-related lens changes (grade > or = 2 in the Lens Opacities Classification System II at the slit lamp) were evaluated in logistic regression analyses by age (persons < 60 years and > or = 60 years). Results are presented as odds ratios (OR) with 95 percent confidence intervals. RESULTS: Of the 1800 participants with lens changes, most had cortical opacities. Diabetes history (18 percent prevalence) was related to all lens changes, especially at younger ages (age < 60 years: OR = 2.23 [1.63, 3.04]; age > or = 60 years: OR = 1.63 [1.22, 2.17]). Diabetes also increased the risk of cortical opacities (age < 60 years: OR = 2.30 [1.63, 3.24]; age > or = 60 years: OR = 1.42 [1.03, 1.96]); additional risk factors were high diastolic blood pressure (age < 60 years: OR = 1.49 [1.00, 2.23] and higher waist/hip ratio (all ages: OR = 1.49 [1.00, 1.84]). Diabetes was also related to posterior subcapsular opacities. Glycated hemoglobin levels were positively associated with cortical and posterior subcapsular opacities. Overall, 14 percent of the prevalence of lens changes could be attributed to diabetes. CONCLUSIONS: The high prevalence of cortical opacities was related to diabetes, hypertension, and abdominal obesity, which also are common in this and other black populations. Interventions to modify these risk factors, especially in populations which they are highly prevalent, may have implications to control visual loss from cataract, which is the first cause of blindness worldwide.(Au)

Implications of hypertension in Barbadians: findings from the Barbados Eye Study Group

Hypertension is the most significant chronic disorder in the Caribbean, affecting approximately 45 percent of adults aged 45 years and older. This condition has significant clinical and public health implications, as elevated blood pressure is associated with considerable morbidity and mortality in populations of black African descent. Here we report some of the cardiovascular implications of blood pressure in Barbadians. The Barbados Eye Study commenced in 1988 and included 4 709 participants or 84 percent of a simple random sample of the island's population aged 40 to 84 years. Measurements included blood pressure (two random zero sphygmomanometer measurements), anthropometry including weight, height and body circumferences, visual acuity, perimetry and applanation tonometry measured by trained observers, and assay of glycated haemoglobin. The median age of the study population was 58 years, 57 percent were female and 93 percent reported their race as black. Among black participants the overall prevalence of hypertension (mean systolic blood pressure > 140 mmHg and/or mean diastolic blood pressure > 90 mmHg and/or a history of antihypertensive treatment) was 55.4 percent with 49.8 percent of men and 59.6 percent of women being affected. The prevalence of self-reported angina in men (based on the Rose questionnaire) was 1 percent in normotensives, 1.3 percent in untreated hypertensives, and 1.5 percent in treated hypertensives. Corresponding prevalences of angina were higher in women, being 2.0 percent, 2.4 percent and 4.5 percent, respectively. The prevalence of self reported myocardial infarction in men was 1.3 percent in normotensives, 2.3 percent in untreated hypertensives and 5.7 percent in treated hypertensives; and, in women, 2.2 percent in normotensives, 2.1 percent in untreated hypertensives and 5.0 percent in hypertensives. The prevalences of cerebrovascular accidents was higher in men than in women: 1.4 percent in normotensive men vs 0.9 percent in normotensive women; 2.3 percent in untreated hypertensive men vs 1.6 percent in untreated hypertensive women; and 6.5 percent in treated hypertensive men vs 4.4 percent in treated hypertensive women.(AU)

Factors associated with hypertension in Barbadians: findings from the Barbados Eye Study cohort

Although hypertension has emerged as the most common chronic non-commuciable disease in the Caribbean, affecting approximately 45 percent of those aged 40 years and older, few studies have attempted to elucidate the contribution of risk factors to the burden of hypertensive disease. The Barbados Eye Study commenced in 1988, and included 4709 participants or 84 percent of a simple random sample of the island's population, aged 40 to 84 years. Measurements included applanation tonometry, visual acuity and perimetry, blood pressure with a random zero sphygmomanometer, anthropometry including weight, height, and body circumferences performed by trained observers, as well as the assay of glycated haemoglobin. The median age of the cohort was 58 years, 57 percent being female, with 93 percent reporting their race as Black. In patients not receiving treatment for hypertension, mean systolic and diastolic pressures were significantly higher in Blacks compared to Whites or others, mean systolic pressure: 132.1 ñ 21.1 mm Hg vs 129.6 ñ 19.8 mm Hg, respectively (p=0.021); mean diastolic pressure: 79.4 ñ 11.3 mm Hg vs 76.1 ñ 10.8 mm Hg, respectively (p=0.001).(AU)

Distribution of intraocular pressure: the Barbados Eye Study

OBJECTIVE: To provide data on the distribution of intraocular pressure (IDP) in a predominantly black population, which has a high prevalence of open-angle glaucoma. DESIGN: Population-based prevalence study. SETTING AND PARTICIPANTS: Participants (N = 4601) (age range, 40-84 years) who had undergone applanation tonometry measurements in the Barbados Eye Study. Self-reported race was 93 percent black, 4 percent mixed (black and white), and 3 percent white or other. DATA COLLECTION: A standardized protocol included applanation tonometry and other ocular measurements, fundus photography, demographic data, and an interview. MAIN OUTCOME MEASURES: The average of 3 IDP measurements at the Barbados Eye Study visit was used to compare IDP by self-reported race. Descriptive data on IDP by age, sex, glaucoma status, and cup-disc ratio were examined in the black population. RESULTS: The IDP was highest in the population of African origin. The mean (+/-SD) IDP values for black, mixed, and white participants were 18.7 +/- 5.2, 18.2 +/-3.8, and 16.5 +/- 3.0 mm Hg, respectively. An IDP greater than 21 mm Hg was present in 18.4 percent, 13.6 percent and 4.6 percent of the black, mixed and white participants, respectively. In analyses that were adjusted for age, sex, and glaucoma status, such values were 5 times as likely in black than white participants and 3.5 times as likely in mixed race participants (p < .01). Among the black participants, the mean IDP increased approximately 1 mm Hg for every increase in 10 years of age. After excluding persons with any type of glaucoma, suspected glaucoma, or a history of glaucoma treatment, women had significantly (P < .01) higher IDP values; however, no significant IDP trends by sex were evident in the group with glaucoma. The IDP was also positively associated (P < .05) with vertical cup-disc ratios. After 2 visits, the IDP remained 21 mm Hg or less in 21 percent of the persons with glaucoma vs 64 percent of those without glaucoma. CONCLUSIONS: In the black participants, the IDP was higher than in the white participants. The IDP was also associated with age and cup-disc ratios. The results showed that open-angle glaucoma and a high IDP alone have a different distribution by sex; although open-angle glaucoma was more frequent in men, ocular hypertension was more frequent in women. These data have implications for the detection and causation of open-angle glaucoma in this high-risk population.(AU)

Prevalence of lens opacities in the Barbados Eye Study

OBJECTIVE: To present population-based data on type and extent of age-related lens opacities in the predominantly black population of the Barbados Eye Study. DESIGN: Prevalence study. SETTING AND PARTICIPANTS: The Barbados Eye Study included 4709 participants (84 percent of those eligible), who were identified from a random sample of Barbadian-born citizens aged 40 to 84 years. DATA COLLECTION: Lens gradings at the slit lamp, obtained with the use of the Lens Opacities Classification System II. MAIN OUTCOME MEASURE: Prevalence of posterior subcapsular, nuclear, and cortical opacities (defined as a grade > or = 2 in either eye), as well as prevalence of any lens changes (including history of previous cataract surgery and/or cataract too advanced to grade). RESULTS: Overall, 41 percent of the Barbados Eye Study population had any lens change, including 3 percent with aphakia or an intraocular lens. Among the population of African descent, cortical opacities (34 percent) were most prevalent, followed by nuclear (19 percent) and posterior subcapsular (4 percent) opacities. Prevalence of all opacity types increased with age (P < .001). Cortical and nuclear opacities were more frequent in women than men. When prevalence of a single kind of opacity was considered, 21 percent of participants had cortical only, 6 percent had nuclear only, and 0.4 percent and posterior subcapsular only; 13 percent had mixed opacities. Visual acuity loss to worse than 20/40 in the more affected eye was present in 48 percent, 26 percent, and 18 percent of nuclear only, posterior subcapsular only, and cortical only types, respectively, and in 53 percent of mixed opacities. CONCLUSIONS: The Barbados Eye Study provides the first prevalence data on different types of lens opacities in a large, predominantly black population. Whereas nuclear opacities are most common in white populations, cortical opacities were the most frequent type in the Barbados Eye Study, a finding of possible etiologic relevance. Other results highlight a higher frequency of opacities in women than men and a high prevalence of visual acuity loss in affected eyes.(AU)

Risk factors for open-angle glaucoma: the Barbados eye study

The objective was to evaluate risk factors for open-angle glaucoma among black participants in the Barbados Eye Study. The design was a population-based study of demographic, medical, ocular, familial, and other factors possibly related to open-angle glaucoma. The setting and participants: The Barbados Eye Study included 4709 Barbados residents identified by a simple random sample of Barbadian-born citizens, 40 to 84 years of age; participation was 84 percent. This report is based on the 4314 black participants examined at the study site; 302 (7 percent) met the Barbados Eye Study criteria for open-angle glaucoma. Data collection included a standardized protocol included applanation tonometry, Humphrey perimetry, fundus photography, blood pressure, anthropometry, and an interview. An ophthalmologic examination was performed for participants who met specific criteria. Main outcome measures: open-angle glaucoma was defined by the presence of both characteristics visual field defects and optic disc damage. Association of open-angle glaucoma with specific factors was evaluated in logistic regression analysis. Results: age, male gender, high intraocular pressure, and family history of open-angle glaucoma were major risk factors; the latter association was stronger in men than women. Lean body mass and cataract history were the only other factors related to open-angle glaucoma. Although hypertension and diabetes were common in Barbados Eye Study participants, they were unrelated to the prevalence of open-angle glaucoma. However, associations were found with low diastolic blood pressure-intraocular pressure differences and low systolic and diastolic blood pressure/intraocular pressure ratios. The Conclusions: In the Barbados Eye Study black population, persons most likely to have open-angle glaucoma were older men and had a family history of open-angle glaucoma, high intraocular pressure, lean body mass, and cataract history. These results suggest the importance of possible genetic or familial factors in open-angle glaucoma. The role of vascular risk factors is consistent with our finding of low blood pressure to intraocular pressure relationships, but the results could be explained by the high intraocular pressure in open-angle glaucoma (AU)