Characteristics of highly myopic eyes: the Beijing Eye Study.

Objective To evaluate factors associated with high myopia (defined as a myopic refractive error exceeding −8 diopters) in a population-based study. Design Population-based prevalence study. Participants The Beijing Eye Study included 4439 participants from among 5324 individuals from a rural area and an urban region of Greater Beijing, ≥40 years old and invited to participate (response rate, 83.4%). Methods Interview and detailed ophthalmic examination. Main Outcome Measures Refractive error, microvascular retinal abnormalities, optic disc morphometry, amount of cataract, and age-related macular changes. Results Fundus photographs and data for refractive error were available for 4319 participants (97.3%; 8484 eyes). In binary logistic regression analysis, prevalence of high myopia was significantly associated with low best-corrected visual acuity ( P P P = 0.31; 95% CI, 1.45–1.75) and α zone of peripapillary atrophy ( P P = 0.020; 95% CI, 0.81–0.98). The highly myopic group had a smaller mean size of macular drusen ( P = 0.03; 95% CI, 0.02–0.26) and a smaller area covered by drusen ( P = 0.01; 95% CI, 0.03–0.22). In the highly myopic group, the predominant drusen type was significantly ( P = 0.01; 95% CI, 0.05–0.41) more often the hard distinct drusen type than the soft drusen type, and visual field defects were significantly more common ( P P P = 0.03; OR, 3.0; 95% CI, 1.21–7.51) and late macular degeneration ( P P = 0.18; 95% CI, 0.76–1.05), focal arteriolar thinning ( P >0.35), arteriolar sheathing ( P >0.45), arteriovenous crossing abnormalities ( P >0.20), self-reported diagnosis of diabetes mellitus ( P = 0.54; OR, 1.36; 95% CI, 0.48–3.80), or arterial hypertension ( P = 0.34; OR, 0.66; 95% CI, 0.32–1.34). Conclusions In the adult Chinese population, high myopia is associated with a lower number, smaller, size and less advanced type of macular drusen, a larger optic nerve head, and decreased best-corrected visual acuity. The risk of early and late macular degeneration was lower for highly myopic participants than for non–highly myopic participants.