Refractive error, ocular and general parameters and ophthalmic diseases. The Beijing Eye Study.

OBJECTIVE: To assess relationships between refractive error and ocular and general parameters.
METHODS: The Beijing Eye Study is a population-based study which included 4,439 Chinese subjects examined in 2001, with a follow-up examination in 2006, in which 3,251 (73.2%) subjects participated.
RESULTS: In multivariate regression analysis, increasing (hyperopic) refractive error was significantly associated with the systemic parameters of higher age (P < 0.001), rural region (P < 0.001), lower education level (P = 0.004), higher frequency of ever smoking (P = 0.02), and higher body mass index (P = 0.02). Adjusted for the systemic parameters, increasing (hyperopic) refractive error was significantly associated with higher best-corrected visual acuity (P < 0.001), lower anterior chamber depth (P < 0.001) and narrower chamber angle (P < 0.001), lower intraocular pressure (P = 0.001), lower amount of nuclear cataract (P = 0.007), smaller beta zone of parapapillary atrophy (P < 0.001), a lower prevalence of open-angle glaucoma (P = 0.01), and a higher prevalence of age-related macular degeneration (P = 0.04). Refractive error was not significantly (P > 0.05) associated with the prevalence of trachoma, non-glaucomatous optic nerve damage, and retinal vein occlusions, nor with mortality.
CONCLUSIONS: In the adult Chinese population, hyperopic subjects compared with myopic subjects were older, lived predominately in the rural regions, had a lower level of education, smoked more, and were more obese. In addition, the hyperopic subjects had a lower intraocular pressure, a higher best-corrected visual acuity, a shallower anterior chamber depth and narrower anterior chamber angle, lower amount of nuclear cataract, smaller beta zone of parapapillary atrophy, a lower prevalence of open-angle glaucoma, and a higher prevalence of age-related macular degeneration.