DISTRIBUTION OF INTRAOCULAR-PRESSURE - THE BARBADOS EYE STUDY

Objective: To provide data on the distribution of intraocular pressure (IOP) in a predominantly black population, which has a high prevalenc e of open-angle glaucoma. Design: Population-based prevalence study. S etting 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% black, 4% mixed (black and whit e), and 3% white or other. Data Collection: A standardized protocol in cluded applanation tonometry and other ocular measurements, fundus pho tography, demographic data, and an interview. Main Outcome Measures: T he average of 3 IOP measurements at the Barbados Eye Study visit was u sed to compare IOP by self-reported race. Descriptive data on IOP by a ge, sex, glaucoma status, and cup-disc ratio were examined in the blac k population. Results: The IOP was highest in the population of Africa n origin. The mean (+/-SD) IOP values for black, mixed, and white part icipants were 18.7+/-5.2, 18.2+/-3.8, and 16.5+/-3.0 mm Hg, respective ly. An IOP greater than 21 mm Hg was present in 18.4%, 13.6%, and 4.6% of the black, mixed, and white participants, respectively. In analyse s that were adjusted for age, sex, and glaucoma status, such values we re 5 times as likely in black than white participants and 3.5 times as likely in mixed race participants (P<.01). Among the black participan ts, the mean IOP increased approximately I mm Hg for every increase in 10 years of age. After excluding persons with any type of glaucoma, s uspected glaucoma, or a history of glaucoma treatment, women had signi ficantly (P<.01) higher IOP values; however, no significant IOP trends by sex were evident in the group with glaucoma. The IOP was also posi tively associated (P<.05) with vertical cup-disc ratios. After 2 visit s, the IOP remained 21 mm Hg or less in 21% of the persons with glauco ma vs 64% of those without glaucoma. Conclusions: In the black partici pants, the IOP was higher than in the white participants. The IOP was also associated with age and cup-disc ratios. The results showed that open-angle glaucoma and a high IOP 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-ri sk population.