title: Relationship of 10-year change in refraction to nuclear cataract and axial length findings from an older population.
abstract: OBJECTIVE
  To examine 10-year changes and other influences on spherical equivalent refraction (SER) in older persons.
  
  
  METHODS
  Prospective population-based study.
  
  
  METHODS
  Three thousand six hundred fifty-four Blue Mountains Eye Study participants 49 or older at baseline (1992-1994) were observed after 5 years (2335; 75% of survivors) and 10 years (1952; 76% of survivors).
  
  
  METHODS
  At each visit, subjective refraction was performed using modified Early Treatment Diabetic Retinopathy Study protocols. Spherical equivalent refraction was calculated as sphere + half cylinder power. Axial length was measured only at the 10-year examinations, using an IOL Master. Right phakic eyes with best-corrected visual acuity > 20/40 (n = 1340) at baseline and 10-year examinations were included.
  
  
  METHODS
  Temporal refractive change.
  
  
  RESULTS
  Over the decade, a hyperopic shift was observed among persons <65 years old, and a myopic shift was associated with increasing age among older subjects, with gender-adjusted mean SER changes of 0.40, 0.33, -0.02, and -0.65 diopters (D) in persons with baseline ages 49 to 54, 55 to 64, 65 to 74 and > or = 75, respectively. Apart from age, myopic refractive change was strongly associated with baseline nuclear cataract; mean changes of -0.96 and 0.26 D were observed in eyes with and without nuclear cataract, respectively (P<0.001). A birth cohort effect on refraction was also observed. After adjusting for age and nuclear cataract, baseline refractive status (P = 0.58), education (P = 0.34), and diabetes (P = 0.16) were not associated with changing SER. A 10% increase in against-the-rule astigmatism was observed over the 10-year period. Axial length showed an age-related reduction in 10-year cross-sectional data, from a mean of 23.61 mm (95% confidence interval [CI], 23.50-23.73) in 59- to 64-year-olds to a mean of 23.15 mm (95% CI, 22.83-23.47) in > or = 85-year-olds. After adjusting for age, education, and nuclear cataract, axial length measured 10 years later was not associated with change in SER (P = 0.34).
  
  
  CONCLUSIONS
  This longitudinal study confirms a hyperopic shift in persons younger than 65 and a myopic shift for older ages. Although underlying causes for this age-related hyperopic shift are unknown, it does not appear related to axial length. The myopic shift, however, is most likely caused by increasing nuclear cataract.
authors.affiliation: Department of Ophthalmology, University of Sydney (Centre for Vision Research, Westmead Millennium Institute, Westmead Hospital), Sydney, Australia.
authors.forename: Reena
authors.initials: R
authors.lastname: Fotedar
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: George
authors.initials: G
authors.lastname: Burlutsky
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001837:Body Weights and Measures; D002386:Cataract / Q000453:epidemiology / Q000503:physiopathology*; D005123:Eye / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006956:Hyperopia / Q000453:epidemiology / Q000503:physiopathology*; D007907:Lens Nucleus, Crystalline / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000453:epidemiology / Q000503:physiopathology*; D009517:New South Wales / Q000453:epidemiology; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*