Objective: To estimate the prevalence of glaucoma and normal intraocular pressure among older adults aged 50 years or above in Shunyi county of Beijing.
Methods: Cluster sampling was used in randomly selecting 5 555 individuals aged 50 years or above in Shunyi county in fall, 1996. The examines received the visual acuity and general eye examination, and in the mean time attention was paid to rule out glaucoma, including inquiry of family and personal history of glaucoma, measurement of anterior chamber depth and intraocular pressure, examination of the optic disc.
Results: The examinations about glaucoma were finished in 4 880 individuals. The response rate was 87.85%. In this population, the prevalence of glaucoma was 2.07%. The prevalence of the primary angle closure glaucoma, primary open angle glaucoma and secondary glaucoma was 1.66%, 0.29% and 0.12% respectively. The prevalence of the variety of glaucoma was increasing by aging. The visual function in 64.00% of glaucoma patients was damaged in certain degree. The rate of the bilateral blindness among glaucoma patients was 16.00%. These patients were all 60 years old or above. The rates of unilateral blindness, bilateral allow vision and unilateral low vision were 17.00%, 23.00% and 8.00%, respectively. The mean and standard deviation of the intraocular pressure among the normal eyes were (13.53 +/- 2.20)mm Hg(1 mm Hg = 0.133 kPa). The tendency of the mean normal intraocular pressure is decreasing by aging.
Conclusions: Glaucoma is a serious eye disease leading to blindness according to the prevalence and the visual function of the glaucoma patients. The mean intraocular pressure among the normal eyes is lower than the expected value. The lower value (18 mm Hg) of the upper limited normal intraocular pressure should be used in screening glaucoma patients among the older adults.