title: Nuclear cataract and myopic shift in refraction.
abstract: OBJECTIVE
  Nuclear cataract is thought to cause a myopic shift in refraction in older persons. The authors tested this hypothesis by assessing the correlation of nuclear opacity with spherical equivalent refraction (SER) in an older population.
  
  
  METHODS
  Population-based cross-sectional study.
  
  
  METHODS
  Three thousand six hundred and fifty-four participants aged 49 years or older were examined in the Blue Mountains Eye Study [BMES] (1992 to 1994). Eye examinations included subjective refraction and lens photographs. Nuclear opacity was assessed against four standard slit-lamp lens photographs using the Wisconsin Cataract Grading System. Nuclear cataract was defined as opacity level 4 or higher.
  
  
  RESULTS
  Participants without nuclear cataract had an annual mean hyperopic shift of 0.05 diopters (P < .0001). In persons with nuclear cataract, this hyperopic shift disappeared. A myopic refractive shift occurred only in persons with nuclear opacity levels of 4 or higher.
  
  
  CONCLUSIONS
  This study documents the contribution of nuclear cataract to the mild myopic shift that neutralizes the age-related hyperopic shift occurring in older persons.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, Sydney, Australia.
authors.forename: Chameen
authors.initials: C
authors.lastname: Samarawickrama
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
authors.forename: George
authors.initials: G
authors.lastname: Burlutsky
authors.forename: Ava G
authors.initials: AG
authors.lastname: Tan
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D002386:Cataract / Q000150:complications*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000503:physiopathology; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000209:etiology* / Q000503:physiopathology; D009517:New South Wales; D012029:Refraction, Ocular / Q000502:physiology