title: Visual impairment, uncorrected refractive error, and objectively measured balance in the United States.
abstract: OBJECTIVE
  Further research is crucial to better understand the reason for falls in individuals with visual impairment (VI) and to develop appropriate fall prevention strategies.
  
  
  OBJECTIVE
  To compare balance measures in individuals with normal vision, VI, and uncorrected refractive error (URE).
  
  
  METHODS
  Cross-sectional study based on a national survey sample.
  
  
  METHODS
  A total of 4590 adults, 40 years or older, participating in the 2001 through 2004 National Health and Nutrition Examination Survey.
  
  
  METHODS
  Participants completed tests of standing balance with eyes open or eyes closed on a firm or compliant (foam) surface. Eyes-closed testing on a foam surface primarily assessed vestibular balance by minimizing visual and proprioceptive inputs. The main outcome measure was time to balance failure on firm and foam surface testing. Participants also self-reported difficulty with falling during the last year.
  
  
  RESULTS
  Failure during eyes-open balance testing conditions or eyes-closed balance testing on a firm surface was not more common among participants with VI-associated or URE-associated vision loss (P > .22). In eyes-closed foam surface balance testing, multivariable models demonstrated higher rates of balance loss with VI-associated vision loss (P = .02) and with URE-associated vision loss (P = .04) (hazard ratio, 1.7 per logarithm of the minimum angle of resolution [logMAR] unit change [10 lines] for both). Self-reported falling difficulty was associated with worse VI (odds ratio, 3.7 per logMAR unit change; P = .03) but not with worse URE (odds ratio, 3.4 per logMAR unit change; P = .14).
  
  
  CONCLUSIONS
  The vestibular contribution to balance (measured with eyes closed on a foam surface) was worse for individuals with VI or URE. Reduced visual inputs may weaken the vestibulo-ocular reflex, an important system that maintains the effectiveness of vestibular balance. Alternately, common degenerative pathways or lower physical activity levels may affect balance, particularly among those with VI.
authors.affiliation: Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Willis
authors.forename: Susan E
authors.initials: SE
authors.lastname: Vitale
authors.forename: Yuri
authors.initials: Y
authors.lastname: Agrawal
authors.forename: Pradeep Y
authors.initials: PY
authors.lastname: Ramulu
mesh_terms: D000058:Accidental Falls; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D004856:Postural Balance / Q000502:physiology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology*; D014481:United States; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities