title: Characteristics of highly myopic eyes: the Beijing Eye Study.
abstract: OBJECTIVE
  To evaluate factors associated with high myopia (defined as a myopic refractive error exceeding -8 diopters) in a population-based study.
  
  
  METHODS
  Population-based prevalence study.
  
  
  METHODS
  The Beijing Eye Study included 4439 participants from among 5324 individuals from a rural area and an urban region of Greater Beijing, > or =40 years old and invited to participate (response rate, 83.4%).
  
  
  METHODS
  Interview and detailed ophthalmic examination.
  
  
  METHODS
  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<0.001; 95% confidence interval [CI], 0.15-0.40), large optic disc size (P<0.001; 95% CI, 1.64-2.25), large size of beta zone (P = 0.31; 95% CI, 1.45-1.75) and alpha zone of peripapillary atrophy (P<0.001; 95% CI, 1.20-1.58), and lower macular drusen count (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<0.001; odds ratio [OR], 24.0; 95% CI, 13.9-41.4) and larger (P<0.001; 95% CI, -1.67 to -1.13). The frequencies of early macular degeneration (P = 0.03; OR, 3.0; 95% CI, 1.21-7.51) and late macular degeneration (P<0.001; OR, 6.33) were significantly lower in the highly myopic group than in the non-highly myopic group. High myopia was not significantly associated with gender (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.
authors.affiliation: Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Yibin
authors.initials: Y
authors.lastname: Li
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
authors.forename: Yaxin
authors.initials: Y
authors.lastname: Wang
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000175:diagnosis* / Q000453:epidemiology; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence; D015593:Retinal Drusen / Q000175:diagnosis* / Q000453:epidemiology; D012424:Rural Population; D014505:Urban Population; D014786:Vision Disorders / Q000175:diagnosis* / Q000453:epidemiology; D014792:Visual Acuity