title: Impaired mesopic visual acuity in eyes with early age-related macular degeneration.
abstract: OBJECTIVE
  To determine photopic and mesopic distance high-contrast visual acuity (HC-VA) and low-contrast visual acuity (LC-VA) in eyes with early age-related macular degeneration (AMD).
  
  
  METHODS
  Measurements were made in 22 subjects with early AMD and 28 healthy control subjects. Inclusion criteria included a photopic HC-VA of 20/25 or better. Distance VA was measured using HC (96%) and LC (10%) Bailey-Lovie logMAR letter charts under photopic (85 cd/m(2)) and mesopic (0.1-0.2 cd/m(2)) luminance conditions.
  
  
  RESULTS
  Mean mesopic distance HC-VA and LC-VA were significantly worse (0.1 logMAR and 0.28 logMAR, respectively) in the early AMD group than in the control group. Under mesopic conditions, the mean difference between LC-VA and HC-VA was significantly greater in the early AMD (0.45 logMAR) than the control group (0.27 logMAR). Mean differences between mesopic versus photopic HC-VA and mesopic versus photopic LC-VA were significantly greater in the early AMD than the control group (0.13 and 0.32 logMAR of difference between the means, respectively). Sensitivity and specificity were significantly greater for mesopic LC-VA than for mesopic HC-VA (Receiver Operating Characteristics, area under the curve [AUC], 0.94 ± 0.030 and 0.76 ± 0.067, respectively). AUC values for photopic HC-VA and LC-VA were below 0.70.
  
  
  CONCLUSIONS
  Visual acuity testing under low luminance conditions emerged as an optimal quantitative measure of retinal function in early AMD.
authors.affiliation: Applied Vision Research Group, Complutense University, Madrid, Spain. puellma@fis.ucm.es
authors.forename: María C
authors.initials: MC
authors.lastname: Puell
authors.forename: Ana R
authors.initials: AR
authors.lastname: Barrio
authors.forename: Catalina
authors.initials: C
authors.lastname: Palomo-Alvarez
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Gómez-Sanz
authors.forename: Amaya
authors.initials: A
authors.lastname: Clement-Corral
authors.forename: María J
authors.initials: MJ
authors.lastname: Pérez-Carrasco
mesh_terms: D000368:Aged; D055253:Color Vision; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008268:Macular Degeneration / Q000150:complications* / Q000503:physiopathology; D008297:Male; D055255:Mesopic Vision / Q000502:physiology*; D008875:Middle Aged; D010775:Photic Stimulation; D014786:Vision Disorders / Q000209:etiology* / Q000503:physiopathology; D014787:Vision Tests; D014792:Visual Acuity; D014796:Visual Perception / Q000502:physiology*