An exploratory study of visual search performance in glaucoma

• Published in: Ophthalmic & physiological optics Vol. 31; no. 3; pp. 225 - 232
• Main Authors: Smith, Nicholas D, Crabb, David P, Garway-Heath, David F
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2011
• Subjects: Activities of Daily Living; Aged; Computer Simulation; Exploratory Behavior - physiology; Female; glaucoma; Glaucoma - physiopathology; Humans; London; Male; search duration; Task Performance and Analysis; visual fields; Visual Perception - physiology; visual search; London
• ISSN: 0275-5408; 1475-1313
• DOI: 10.1111/j.1475-1313.2011.00836.x

Citation information: Smith ND, Crabb DP & Garway‐Heath DF. An exploratory study of visual search performance in glaucoma. Ophthalmic Physiol Opt 2011, 31, 225–232. doi: 10.1111/j.1475‐1313.2011.00836.x Purpose:  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). Conclusion:  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.