title: Compensatory strategy use identifies risk of incident disability for the visually impaired.
abstract: BACKGROUND
  Use of compensatory strategies may be a marker for preclinical disability.
  
  
  OBJECTIVE
  To determine, among persons who did not report mobility disability, if the reported use of compensatory strategies was a predictor of subsequent disability at 2 years in those who did and did not have visual impairment at baseline.
  
  
  METHODS
  Within a population-based sample of 2520 persons aged 65 to 84 years, those who reported no difficulty walking or stair-climbing at baseline (not disabled) were studied. Visual impairment was defined as a visual acuity worse than 20/40, log contrast sensitivity less than 1.5, or more than 30 points missing in the visual field. Use of compensatory strategies at baseline was reported as changing the frequency or method used to walk or climb stairs. Incident disability was defined as report of new difficulty in mobility at 2 years.
  
  
  RESULTS
  Those using compensatory strategies at baseline were 3 times more likely to report incident disability in walking and stair-climbing, compared with persons who did not use compensatory strategies. Visual field impairment was the most significant predictor of incident mobility disability of all the vision measures studied. Among those with visual field impairment, users of compensatory strategies were 3 times more likely to report incident walking disability (95% confidence interval, 1.87-5.58) and incident stair-climbing disability (95% confidence interval, 1.86-4.83) compared with those who did not use compensatory strategies.
  
  
  CONCLUSIONS
  Preclinical disability, characterized by use of compensatory strategies in those with no disability, is a predictor for subsequent disability and may help identify patients with visual impairment for whom mobility interventions are warranted.
authors.affiliation: Dana Center for Preventive Ophthalmology and Lions Low Vision Center, Wilmer Eye Institute, The Johns Hopkins University, 600 N. Wolfe Street, Rm. 129, Baltimore, MD 21287, USA. shwest@jhmi.edu
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
authors.forename: Beatriz
authors.initials: B
authors.lastname: Munoz
authors.forename: Gary S
authors.initials: GS
authors.lastname: Rubin
authors.forename: Karen
authors.initials: K
authors.lastname: Bandeen-Roche
authors.forename: Aimee T
authors.initials: AT
authors.lastname: Broman
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Turano
mesh_terms: D000203:Activities of Daily Living; D000222:Adaptation, Physiological; D000368:Aged; D000369:Aged, 80 and over; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D015994:Incidence; D008297:Male; D008396:Maryland / Q000453:epidemiology; D009043:Motor Activity; D012307:Risk Factors; D014786:Vision Disorders / Q000453:epidemiology* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*; D016138:Walking