title: Effect of uncorrected astigmatism on vision.
abstract: OBJECTIVE
  To examine the effect of uncorrected astigmatism in older adults.
  
  
  METHODS
  University vision clinic.
  
  
  METHODS
  Investigational simulation.
  
  
  METHODS
  Healthy adult presbyopes had astigmatism of 0.00 to -4.00 diopters cylinder (DC) × 90 degrees and -3.00 DC × 90, × 180, and × 45 degrees induced with spectacle lenses, with the mean spherical equivalent compensated to plano, in random order. Visual acuity was assessed binocularly using a computerized test chart at 95%, 50%, and 10% contrast. Near acuity and reading speed were measured using standardized reading texts. Light scatter was quantified with a C-Quant straylight meter and driving reaction times with a computer simulator. Visual clarity of a mobile phone and computer screen was subjectively rated.
  
  
  RESULTS
  Distance visual acuity in the 21 volunteers decreased with increasing uncorrected astigmatic power (F = 174.50, P < .001) and at lower contrasts (F = 170.77, P < .001). Near visual acuity and reading speed also decreased with increasing uncorrected astigmatism power (P < .001). Light scatter was not significantly affected by uncorrected astigmatism (P > .05); however, the reliability and variability of measurements decreased with increasing uncorrected astigmatic power (P < .05). Driving simulator performance was unaffected by uncorrected astigmatism (P > .05), although subjective rating of clarity decreased with increasing uncorrected astigmatic power (P < .001). Uncorrected astigmatism at the 45-degree or 180-degree orientation resulted in worse distance and near visual acuity and subjective-rated clarity than at the 90-degree orientation (P < .05).
  
  
  CONCLUSIONS
  Uncorrected astigmatism, even as low as 1.00 D, caused significantly decreased vision and if left uncorrected could significantly affect patients' independence, quality of life, and well-being.
authors.affiliation: Aston University, School of Life and Health Sciences, Ophthalmic Research Group, Birmingham, United Kingdom. j.s.w.wolffsohn@aston.ac.uk
authors.forename: James S
authors.initials: JS
authors.lastname: Wolffsohn
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Bhogal
authors.forename: Sunil
authors.initials: S
authors.lastname: Shah
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D001251:Astigmatism / Q000503:physiopathology* / Q000628:therapy; D001334:Automobile Driving; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D011305:Presbyopia / Q000503:physiopathology; D011788:Quality of Life; D011932:Reading; D012542:Scattering, Radiation; D014786:Vision Disorders / Q000503:physiopathology*; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*