title: Vision and quality in the digital imaging environment: how much does the visual acuity of radiologists vary at an intermediate distance?
abstract: OBJECTIVE
  The purpose of this study was to examine the intermediate-distance visual acuity of a cross section of radiologists and to identify variation in visual acuity during a typical workday.
  
  
  METHODS
  Forty-eight radiologists completed a brief survey before undergoing visual acuity testing, with corrective lenses if routinely used, at three times of the day. Testing was performed with modified versions of a U.S. Federal Aviation Administration visual acuity test instrument.
  
  
  RESULTS
  The mean acuity of radiologists across all measurements was 20/15 (logarithm of the minimum angle of resolution [logMAR], -0.109 +/- 0.105 [SD]). Visual acuity ranged from 20/30 to 20/10 (logMAR, 0.176 to -0.301). Mean visual acuity in the morning session was approximately 20/16 (logMAR, -0.0856). This value was statistically significantly lower than the mean visual acuity in both the early afternoon (logMAR, -0.124; p = 0.003) and the late afternoon (logMAR, -0.118; p = 0.015), both of which were approximately 20/15. This change was within the expected test-retest variability of Snellen acuity measurements.
  
  
  CONCLUSIONS
  Although a statistically significant difference was detected between the visual acuity of radiologists in the morning and acuity in other parts of the day, this difference was relatively modest and within previously published ranges of variability for similar visual acuity tests. It is unlikely that such variation in visual acuity among radiologists influences diagnostic performance. Not every radiologist had 20/20 vision, a few needed visual correction, and more than a few had not undergone a thorough eye examination for as many as 15 years before the study.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, 21201, USA. nsafdar@umm.edu
authors.forename: Nabile M
authors.initials: NM
authors.lastname: Safdar
authors.forename: Khan M
authors.initials: KM
authors.lastname: Siddiqui
authors.forename: Farah
authors.initials: F
authors.lastname: Qureshi
authors.forename: Muhammad Kashif
authors.initials: MK
authors.lastname: Mirza
authors.forename: Nancy
authors.initials: N
authors.lastname: Knight
authors.forename: Paul
authors.initials: P
authors.lastname: Nagy
authors.forename: Eliot
authors.initials: E
authors.lastname: Siegel
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010154:Pakistan; D010820:Physicians / Q000706:statistics & numerical data*; D011785:Quality Assurance, Health Care / Q000706:statistics & numerical data*; D011856:Radiographic Image Enhancement; D011871:Radiology / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014481:United States; D014787:Vision Tests / Q000706:statistics & numerical data*; D014792:Visual Acuity; D000078329:Workforce