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)

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)

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)

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)

The Barbados eye study: major prevalence findings - abstract

This study has been designed to provide information about the visual loss in the predominantly Afro-Caribbean population in Barbados. The prevalence, incidence and risk factors of eye disease were studied in a random population sample of 4,709 Barbadian-born people 40 - 84 years of age. Data collected included visual acuity, applanation tonometry, automated perimetry, lens grading, disc and macula photographs along with histories and other clinical measurements such as blood pressure. Data on visual acuity showed that 12 percent of subjects had impairment of vision worse than 6/12 whislt 3.4 percent had severe loss ( > 6/60). Open angle glaucoma (OAG) was diagnosed on the criteria of visual field loss and typical optic disc pathology in at least one eye. Six percent (309 persons) were diagnosed as having OAG, 3.6 percent as suspect OAG and 12 percent had intraocular pressure higher than 21 mm Hg. Prevalence of OAG increased with age, reaching 25 percent in men and 22 percent in women 80 years of age and over. Half of the cases found had been previously diagnosed. Analysis suggests that the risk factors for OAG are: older age, males, high intraocular pressures, a history of cataract and a lean body mass. Diabetes, hypertension, cardiovascular disease and obesity were not identified as risk factors in this study. Lens opacities were frequent (44 percent), and increased in frequency with age. Of those persons with visual acuity less than 6/12, 75 percent had cataracts. These findings should be helpful in implementing blindness prevention programmes (AU)

The Barbados eye study

OBJECTIVE: To describe the design of the Barbados Eye Study and report of the prevalence of open angle glaucoma (OAG) in a predominantly black study population. DESIGN: Population-bases prevalence study. SETTING AND PARTICIPATION: Residents of Barbados, West Indies, identified from a simple random sample of Barbadian-born citizens 40 through 84 years old. DATA COLLECTION: Participants had a comprehensive study visit that included automated perimetry, applanation tonometry, and fundus photography; persons with specific findings, as well as a 10 percent sample of participants, were referred for an ophthalmologic exanimation and additional tests. OUTCOME: A diagnosis of OAG required both visual field and optic disc criteria for glaucoma damage after excluding other causes. RESULTS: The 4709 participants (83.5 percent of those eligible) had demographic characteristics that were similar to the census population. Of the 4631 participants who were tested at the study site, 95 percent completed Humphrey automated perimetry and 97 percent had photographic or clinical disc gradings; 93 percent of those referred completed the ophthalmologic examination. In the adult population, the prevalence of OAG by self-reported race was 7.0 percent (302/4314) in black, 3.3 percent (6/184) in mixed race, and 0.8 percent (1/1`33) in white or other participants. In black and mixed-race participants, the prevalence reached 12 percent at age 60 years and older and was higher in men (8.3 percent) than in women (5.7 percent), with and age-adjusted male-female ratio of 1.4. In addition, over 3 percent of the participants were classified as having suspect OAG. CONCLUSIONS: To our knowledge, the Barbados Eye Study is the largest glaucoma study ever conducted in a black population and identified more people with OAG than did any previous population study. The prevalence of OAG was high, especially at older ages and in men. Among participants 50 years old or older, one in 11 had OAG, and prevalence increased to one in six at age 70 years or older. The results highlights the public health importance of OAG in the Afro-Caribbean region and have implications for other populations. (AU)

Comparison of diabetic retinopathy detection by clinical examinations and photograph gradings. Barbados (West Indies) eye study group

OBJECTIVE: To compare the use of clinical examination and fundus photograph gradings in detecting diabetes. DESIGN: Population-based epidemiologic study. SETTING: Sir Winston Scott Polyclinic, Bridgetown, Barbados,West Indies. PARTICIPANTS; Subset of a random sample of the country's population aged 40 to 86 years. RESULTS: Among 1168 black persons with fundus photograph evaluations, opthalmologic examinations, diabetes history, and glycated hemoglobin data, 21 percent reported a history of diabetes: 9.5 percent had definite diabetes (glycated hemoglobin > 11.5 percent ); and 13.3 percent had a diabetes history and glycated hemoglobin value less than or equal to 11.5 percent. The frequency of diabetic retinopathy in this group was 7.7 percent (90/1168) by clinical examination, 8.7 percent (102/1168) by photograph gradings, and 6.7 percent (78/1168) by both methods. CONCLUSION: These results suggest that in certain populations that include diabetics and nondiabetics, a clinical examination by an ophthalmologist will detect most cases of diabetic retinopathy identified by disc and macula photographs read by skilled graders. However, it will lead to an underestimate of prevalence. Staff availability and cost, issues not examined in this study, should determine which approach is selected (AU)

The Barbados eye study: design and progress report - abstract

The Barbados Eye Study is determining the prevalence and risk factors of major causes of visual loss in a random sample of the population between ages 40 and 84 years. All participants have visual acuity (VA) measurements, applanation tonometry, computerized perimetry, lens gradings, fundus photography, glycosylated haemoglobin, interview, blood pressure and anthropometry. Persons with positive test results and a 10 percent sample of all participants also have an opthalmologic examination, additional threshold perimetry and tonometry. The study also has a longitudinal component, the glaucoma follow-up study, which provides continuing care and evaluation for newly detected cases of glaucoma and suspect glaucoma. Recruitment of the intended sample size of 4,000 persons is expected to end in 1991. By November 1990, 3,095 persons had completed data collection with a participation of 87 percent of those eligible. Preliminary findings show a prevalence of visual impairment (VA < 20/40 in the better eye) of 11.5 percent, age-related cataract, age-related maculopathy, open-angle glaucoma and diabetic retinopathy were main causes of decreased VA. Blindness prevalence (VA < 20/200 in the better eye) was 3.2 percent; open-angle glaucoma and age-related cataract were the major causes of blindness. Results suggest a high prevalence of open-angle glaucoma as found in an earlier pilot project. Hypertension and diabetes mellitus were also very frequent in this population (AU)

A pilot project of glaucoma in Barbados

The prevalence of open-angle glaucoma is believed to be very high among West Indian blacks. To begin investigating the prevalence and risk factors for glaucoma and other eye diseases in Barbados, WI, a pilot study was conducted. The pilot project identified a stratified, random national sample of 300 persons over 35 years of age who were invited to participate in an ophthalmic examination and an interview. Of those contacted 89 percent were eligible and 95 percent of these agreed to participate. The overall glaucoma prevalence in the participants was 6 percent; it was 13 percent among black and mixed persons over 54 years. Age related cataract, hypertension, and diabetes were frequent findings. Although the sample size of the pilot project is small, the results suggest a high prevalence of glaucoma in Barbados, a finding that merits further study. (AU)

The results of glaucoma surgery in West Indians - abstract

As glaucoma is the most frequent cause of blindness in Barbados, changes in treatment are being sought. Glaucoma drainage surgery was performed on 46 eyes which had open angle glaucoma uncontrolled by medical means. All the patients were deeply pigmented West Indians. The short term assessment of results has been made on a return of the intraocular tension to normal without apparent visual deterioration. Of the 46 eyes, the tension has been normalized in 67 percent and these patients are now maintained without treatment. In 20 percent miotic drops are required and in 4 percent drops and Diamox are necessary to normalize the tension. In 9 percent improvement was not satisfactory. Because of the usually satisfactory results, surgery should be offered to glaucoma patients at an earlier stage, even to patients with deeply pigmented eyes (AU)