title: The association between myopia and various subtypes of lens opacity: SEE (Salisbury Eye Evaluation) project.
abstract: OBJECTIVE
  To establish the relationship between myopia and lens opacity.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  Two thousand five hundred twenty participants from the Salisbury Eye Evaluation aged 65 to 84 years.
  
  
  METHODS
  Participants filled out questionnaires regarding medical history, social habits, and a detailed history of distance spectacle wear. They underwent a full ocular examination. Lens photographs were taken for assessment of lens opacity using the Wilmer grading system. Multivariate logistic regression models using generalized estimating equations were used to analyze the relationship between lens opacity type and degree of myopia, while accounting for potential confounders.
  
  
  METHODS
  Presence of posterior subcapsular opacity, cortical opacity, or nuclear opacity.
  
  
  RESULTS
  Significant associations were found between myopia and both nuclear and posterior subcapsular opacities. For nuclear opacity, the odds ratios (ORs) were 2.25 for myopia between -0.50 diopters (D) and -1.99 D (P<0.001), 3.65 for myopia between -2.00 D and -3.99 D (P<0.001), 4.54 for myopia between -4.00 D and -5.99 D (P<0.001), and 3.61 for myopia -6.00 D or more (P = 0.002). For posterior subcapsular cataracts, ORs were 1.59 for myopia between -0.50 D and -1.99 D (P = 0.11), 3.22 for myopia between -2.00 D and -3.99 D (P = 0.002), 5.36 for myopia between -4.00 D and -5.99 D (P<0.001), and 12.34 for myopia -6.00 D or more (P<0.001). No association was found between myopia and cortical opacity. The association between posterior subcapsular opacity and myopia was equally strong for those wearing glasses by age 21 years and for those without glasses; for nuclear opacity, significantly higher ORs were found for myopes who started wearing glasses after age 21.
  
  
  CONCLUSIONS
  These results confirm the previously reported association between myopia, posterior subcapsular opacity, and nuclear opacity. Furthermore, the strong association between early spectacle wear and posterior subcapsular opacity among myopes, absent for nuclear opacity, suggests that myopia may precede opacity in the case of posterior subcapsular opacity, but not nuclear opacity. Measures of association between posterior subcapsular opacity and myopia were stronger in the current study than have previously been found. Longitudinal studies to confirm the association are warranted.
authors.affiliation: Wilmer Eye Institute and the Dana Center for Preventive Ophthalmology, Johns Hopkins University Schools of Medicine and Public Health, Baltimore, Maryland 21287, USA.
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Chang
authors.forename: Nathan G
authors.initials: NG
authors.lastname: Congdon
authors.forename: Irina
authors.initials: I
authors.lastname: Bykhovskaya
authors.forename: Beatriz
authors.initials: B
authors.lastname: Munoz
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000145:classification* / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005139:Eyeglasses / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008396:Maryland / Q000453:epidemiology; D009216:Myopia / Q000453:epidemiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014792:Visual Acuity