title: Associations between abnormal rod-mediated dark adaptation and health and functioning in older adults with normal macular health.
abstract: OBJECTIVE
  Delayed rod-mediated dark adaptation (DA) is characteristic of early age-related macular degeneration (AMD) and also can be observed in some older adults in normal macular health. We examine cross-sectional associations between rod-mediated DA and risk factors for AMD in older adults in normal macular health.
  
  
  METHODS
  The sample consisted of adults aged ≥60 years old in normal macular health per grading of fundus photos using an established disease classification system. Rod-mediated DA was measured psychophysically following a photobleach using a computer-automated dark adaptometer with targets centered at 5° on the inferior vertical meridian. The speed of DA was characterized by the rod-intercept value, with abnormal DA defined as rod-intercept ≥ 12.3 minutes. We assessed several health and functional characteristics that the literature has suggested increase AMD risk (e.g., smoking, alcohol use, inflammatory markers, apolipoproteins, low luminance visual acuity, chronic medical conditions, body mass, family history).
  
  
  RESULTS
  Among 381 participants (mean age, 68.5 years; SD, 5.5), 78% had normal and 22% had abnormal DA, with the prevalence of abnormal DA increasing with age. After age-adjustment, abnormal DA was associated with increased odds of elevated C-reactive protein (CRP), heavy use of or abstention from alcohol, high blood pressure, and drop in visual acuity under mesopic conditions.
  
  
  CONCLUSIONS
  Despite having normal macular health according to accepted definitions of AMD presence, approximately one-quarter of older adults recruited from primary eye care clinics had abnormal DA, which was associated with known risk factors for AMD, including elevated CRP.
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Owsley
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Carrie
authors.initials: C
authors.lastname: Huisingh
authors.affiliation: Department of Ophthalmology, Penn State College of Medicine, Hershey, Pennsylvania, United States.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Jackson
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Curcio
authors.affiliation: Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Szalai
authors.affiliation: Division of Gerontology and Geriatrics, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Nassrin
authors.initials: N
authors.lastname: Dashti
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Clark
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Kia
authors.initials: K
authors.lastname: Rookard
authors.affiliation: Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Mark A
authors.initials: MA
authors.lastname: McCrory
authors.affiliation: Division of Clinical Immunology and Rheumatology, Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Tyler T
authors.initials: TT
authors.lastname: Wright
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Callahan
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Lanning B
authors.initials: LB
authors.lastname: Kline
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: C Douglas
authors.initials: CD
authors.lastname: Witherspoon
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Gerald
authors.initials: G
authors.lastname: McGwin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003430:Cross-Sectional Studies; D003623:Dark Adaptation / Q000502:physiology*; D005260:Female; D006801:Humans; D008266:Macula Lutea / Q000502:physiology*; D008268:Macular Degeneration / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011594:Psychometrics / Q000379:methods; D012016:Reference Values; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D014792:Visual Acuity
keywords: age-related macular degeneration; aging; dark adaptation; rod function