title: Visual ability of patients seeking outpatient low vision services in the United States.
abstract: OBJECTIVE
  Most patients with low vision are elderly and have functional limitations from other health problems that could add to the functional limitations caused by their visual impairments.
  
  
  OBJECTIVE
  To identify factors that contribute to visual ability measures in patients who present for outpatient low vision rehabilitation (LVR) services.
  
  
  METHODS
  As part of a prospective, observational study of new patients seeking outpatient LVR, 779 patients from 28 clinical centers in the United States were enrolled in the Low Vision Rehabilitation Outcomes Study (LVROS) from April 25, 2008, through May 2, 2011. The Activity Inventory (AI), an adaptive visual function questionnaire, was administered to measure overall visual ability and visual ability in 4 functional domains (reading, mobility, visual motor function, and visual information processing) at baseline before LVR. The Geriatric Depression Scale, Telephone Interview for Cognitive Status, and Medical Outcomes Study 36-Item Short-Form Health Survey physical functioning questionnaires were also administered to measure patients' psychological, cognitive, and physical health states, respectively.
  
  
  METHODS
  Predictors of visual ability and functional domains as measured by the AI.
  
  
  RESULTS
  Among the 779 patients in the LVROS sample, the mean age was 76.4 years, 33% were male, and the median logMAR visual acuity score was 0.60 (0.40-0.90 interquartile range). Correlations were observed between logMAR visual acuity and baseline visual ability overall (r = -0.42) and for all functional domains. Visual acuity was the strongest predictor of visual ability (P  < .001) and reading ability (P < .001) and had a significant independent effect on the other functional domains. Physical ability was independently associated with (P < .001) overall visual ability as well as mobility and visual motor function. Depression had a consistent independent effect (P < .001) on overall visual ability and on all functional domains, whereas cognition had an effect on only reading and mobility (P < .001).
  
  
  CONCLUSIONS
  Visual ability is a multidimensional construct, with visual acuity, depression, physical ability, and cognition explaining more than one-third of the variance in visual ability as measured by the AI. The significant contributions of the nonvisual factors to visual ability measures and the rehabilitation potential (ie, ceiling) effects they may impose on LVR are important considerations when measuring baseline visual ability and ultimately LVR outcomes in ongoing clinical research.
authors: Lions Vision Research and Rehabilitation Center, Wilmer Eye Institute, the Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors: Judith E
authors: JE
authors: Goldstein
authors: Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors: Melissa W
authors: MW
authors: Chun
authors: Department of Ophthalmology, Smith-Kettlewell Eye Research Institute, California Pacific Medical Center, San Francisco4Department of Ophthalmology, University of Kansas, Kansas City.
authors: Donald C
authors: DC
authors: Fletcher
authors: Lions Vision Research and Rehabilitation Center, Wilmer Eye Institute, the Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors: James T
authors: JT
authors: Deremeik
authors: Lions Vision Research and Rehabilitation Center, Wilmer Eye Institute, the Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors: Robert W
authors: RW
authors: Massof
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care / Q000706:statistics & numerical data*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics; D011597:Psychomotor Performance; D011932:Reading; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014481:United States; D015354:Vision, Low / Q000503:physiopathology / Q000534:rehabilitation*; D014792:Visual Acuity / Q000502:physiology*; D014796:Visual Perception; D019987:Persons with Visual Disabilities / Q000534:rehabilitation*; D016138:Walking