title: Comparison of Visual Function in Older Eyes in the Earliest Stages of Age-related Macular Degeneration to Those in Normal Macular Health.
abstract: OBJECTIVE
  To compare the ability of several visual functional tests in terms of the strength of their associations with the earliest phases of age-related macular degeneration (AMD), which bears on their potential to serve as functional endpoints in evaluating treatments for early AMD and prevention strategies.
  
  
  METHODS
  Eyes from adults ≥60 years old were identified as being in normal macular health or in the earliest stages of AMD (steps 2, 3 or 4) through grading of color stereo-fundus photos by an experienced grader masked to all other study variables who used the 9-step Age-Related Eye Disease Study (AREDS) classification system for AMD severity. Visual function was assessed using the following tests: best-corrected visual acuity, low luminance visual acuity, spatial contrast sensitivity, macular cone-mediated light sensitivity and rod-mediated dark adaptation.
  
  
  RESULTS
  A total of 1260 eyes were tested from 640 participants; 1007 eyes were in normal macular health (defined as step 1 in AREDS system) and 253 eyes had early AMD (defined as steps 2, 3 or 4). Adjusting for age and gender, early AMD eyes had two times the odds of having delayed rod-mediated dark adaptation than eyes in normal macular health (p = 0.0019). Visual acuity, low luminance acuity, spatial contrast sensitivity and macular light sensitivity did not differ between normal eyes and early AMD eyes.
  
  
  CONCLUSIONS
  Eyes in the earliest phases of AMD were two times more likely to have delayed rod-mediated dark adaptation, as assessed by the rod-intercept, as compared to older eyes in normal macular health, whereas there was no difference in early AMD versus normal eyes in tests of visual acuity, low luminance acuity, macular light sensitivity and spatial contrast sensitivity.
authors: a Department of Ophthalmology , School of Medicine, University of Alabama at Birmingham , Birmingham , AL , USA .
authors: Cynthia
authors: C
authors: Owsley
authors: a Department of Ophthalmology , School of Medicine, University of Alabama at Birmingham , Birmingham , AL , USA .
authors: Carrie
authors: C
authors: Huisingh
authors: a Department of Ophthalmology , School of Medicine, University of Alabama at Birmingham , Birmingham , AL , USA .
authors: Mark E
authors: ME
authors: Clark
authors: b MacuLogix Inc. , Hummelstown , PA , USA , and.
authors: Gregory R
authors: GR
authors: Jackson
authors: a Department of Ophthalmology , School of Medicine, University of Alabama at Birmingham , Birmingham , AL , USA .|c Department of Epidemiology , School of Public Health, University of Alabama at Birmingham , Birmingham , AL , USA.
authors: Gerald
authors: G
authors: McGwin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D055253:Color Vision / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D003430:Cross-Sectional Studies; D003623:Dark Adaptation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D055254:Night Vision / Q000502:physiology*; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology*; D057135:Wet Macular Degeneration / Q000145:classification / Q000503:physiopathology*
keywords: Age-related macular degeneration; aging; dark adaptation; functional endpoints; visual function