title: Normal range of cambridge low contrast test; a population based study.
abstract: OBJECTIVE
  To determine the range of contrast sensitivity (CS) and its determinants in a normal population, Mashhad, Iran.
  
  
  METHODS
  In this cross-sectional population based study, 4,453 individuals were invited of whom 3,132 persons agreed to participate (response rate, 70.4%). CS data from 2,449 eligible individuals were analyzed. CS was determined using the Cambridge low contrast square-wave grating test, and its associations with age, gender, best-corrected visual acuity (BCVA) and manifest refraction spherical equivalent (MRSE) refractive error, were analyzed.
  
  
  RESULTS
  Mean age of the participants was 29.1±17.3 (range, 4-89) years and 66.4% were female. Mean CS was 239.6±233.3 and 234.6±228.6 cps in right and left eyes, respectively. Mean binocular CS was 310.9±249.0 cps. Multiple linear regression showed that CS was inversely correlated with older age (β=-1.1, P<0.001), female gender (β=-40.1, P<0.001), poorer BCVA (β=-165.4, P<0.001), and severity of myopia (β=-10.2, P<0.001).
  
  
  CONCLUSIONS
  The normal range of Cambridge low-contrast grating test reported herein may serve as a reference for the general population in Iran. Our findings can be used for both research and clinical applications, particularly for evaluations of the outcomes of refractive surgery. In the current study, CS was lower in older subjects, myopic individuals and patients with lower BCVA.
authors: Refractive Error Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Hadi
authors: H
authors: Ostadimoghaddam
authors: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors: Akbar
authors: A
authors: Fotouhi
authors: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors: Hassan
authors: H
authors: Hashemi
authors: Refractive Error Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Abbas Ali
authors: AA
authors: Yekta
authors: Refractive Error Research Center, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran ; Department of Optometry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors: Javad
authors: J
authors: Heravian
authors: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors: Tahereh
authors: T
authors: Abdolahinia
authors: Dezful University of Medical Sciences, Dezful, Iran.
authors: Reza
authors: R
authors: Norouzi Rad
authors: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors: Soheila
authors: S
authors: Asgari
authors: Department of Epidemiology, Faculty of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Mehdi
authors: M
authors: Khabazkhoob
keywords: Cambridge Test; Contrast Sensitivity; Normal Value; Population Based Study