title: Longitudinal relationships among visual acuity and tasks of everyday life: the Salisbury Eye Evaluation study.
abstract: OBJECTIVE
  To study the relationships among visual and physical function trajectories of aging adults.
  
  
  METHODS
  The community-based random sample consists of 2520 adults who were aged 65 to 84 years in 1993 to 1995 and reassessed 2, 6, and 8 years later. Presenting and best-corrected Early Treatment Diabetic Retinopathy Study visual acuity were obtained. Activities of daily living (ADLs) and instrumental ADLs (IADLs) were evaluated through survey instruments. Growth curve models were used to simultaneously estimate health trajectories and obtain associations among the trajectories while controlling for relevant covariates.
  
  
  RESULTS
  Best-corrected acuity (logMAR) worsened by an average of 0.013 (∼1 letter) annually. ADL difficulties increased by 0.22 standard deviations (SD) and IADL difficulties increased by 0.28 SD annually. Controlling for demographic and health covariates, visual acuity rates of decline correlated with rates of increase in ADL difficulties (r = 0.15, P = 0.05) and IADL difficulties (r = 0.41, P < 0.001). Acuity loss was significantly related to increases in ADLs for men (b = 0.039, P < 0.01), but not for women (b = 0.001, P > 0.9). The direct effects of acuity loss were strongest for IADLs where a 1-unit decline in acuity (logMAR) was associated with a 0.067 SD increase in IADL difficulties (P < 0.001) at baseline, and a 1-unit acuity decline (logMAR) per year resulted in a 0.10 SD unit increase in the rate of change in IADL difficulties (P < 0.001) per year.
  
  
  CONCLUSIONS
  Over time, increases in visual acuity loss were related to increased IADL difficulties in men and women and increases in ADL difficulties for men only. The findings support the importance of maintaining vision in older adults.
authors.affiliation: Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida 33136, USA. blam@med.miami.edu
authors.forename: Byron L
authors.initials: BL
authors.lastname: Lam
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Christ
authors.forename: D Diane
authors.initials: DD
authors.lastname: Zheng
authors.forename: Sheila K
authors.initials: SK
authors.lastname: West
authors.forename: Beatriz E
authors.initials: BE
authors.lastname: Munoz
authors.forename: Bonnielin K
authors.initials: BK
authors.lastname: Swenor
authors.forename: David J
authors.initials: DJ
authors.lastname: Lee
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D012307:Risk Factors; D014786:Vision Disorders / Q000453:epidemiology* / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*