title: An exploratory study of visual search performance in glaucoma.
abstract: OBJECTIVE
  Visual search plays an integral role in many daily activities. This study aimed to determine whether patients with glaucoma are slower than visually healthy age-matched individuals when searching for items in computer displayed images.
  
  
  METHODS
  Forty participants were recruited for the study: 20 patients with a clinical diagnosis of glaucoma and 20 age-similar visually healthy control subjects. All participants had visual acuity of 6/12 or better. Participants were presented with 20 images with Landolt C symbols and 15 photographic images of everyday scenes on a computer. The time taken by each participant to locate a specified item in each image was recorded. Average search times were calculated across participants and compared between groups.
  
  
  RESULTS
  All the patients had visual field defects in both eyes. On average, the patients also differed from control subjects by binocular contrast sensitivity measurements (p = 0.01) and visual acuity (p = 0.003). The patients (mean age = 67 years, S.D.: 10 years) and controls (mean age: 67 years, S.D.: 11 years) were age similar (p = 0.40). The median search time for patients finding target items in photographs of everyday scenes was 15.2 s (interquartile range 9.4-20.6 s) and this was significantly slower than the median time (10.0 s; interquartile range 7.2-10.3 s) taken by the controls (p = 0.007). There was no statistical evidence for a difference in median search times between groups in the Landolt C search task (p = 0.24).
  
  
  CONCLUSIONS
  Some individuals with glaucomatous visual field defects in both eyes find it especially difficult to locate objects in photographs of everyday scenes when compared to visually healthy individuals of a similar age.
authors.affiliation: Department of Optometry and Visual Science, City University London, London, UK.
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Smith
authors.forename: David P
authors.initials: DP
authors.lastname: Crabb
authors.forename: David F
authors.initials: DF
authors.lastname: Garway-Heath
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003198:Computer Simulation; D005106:Exploratory Behavior / Q000502:physiology*; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D008131:London; D008297:Male; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology*