title: Grading contact lens complications under time constraints.
abstract: OBJECTIVE
  To investigate the effect of observation time on the precision of grading the severity of contact lens complications.
  
  
  METHODS
  Twenty-five optometry students used the Efron Grading Scales for Contact Lens Complications to grade the severity of one image of each of the 16 forms of anterior eye pathology depicted in the Efron scales. This procedure was repeated for observation times of 0.1, 2, and 60 s.
  
  
  RESULTS
  Overall, significantly greater grading precision (smaller standard deviation of mean grades) was demonstrated for longer observation times (p < 0.004); however, certain complications appear to require longer observation times for precise grading. There was a highly significant dependence of the mean grade on image (p < 0.0001), observation time (p < 0.0001), and observation time-image interaction (p < 0.0001).
  
  
  CONCLUSIONS
  Overall, a brief viewing time of a few seconds is typically all that is required for precise grading of ocular complications of contact lens wear. Some forms of pathology are more complex and may require more time to grade precisely.
authors: Institute of Health and Biomedical Innovation, and School of Optometry, Queensland University of Technology, Kelvin Grove, Australia. n.efron@qut.edu.au
authors: Nathan
authors: N
authors: Efron
authors: Sophia
authors: S
authors: McCubbin
mesh_terms: D003196:Computer Graphics; D003229:Conjunctival Diseases / Q000175:diagnosis* / Q000209:etiology; D003261:Contact Lenses / Q000009:adverse effects*; D003316:Corneal Diseases / Q000175:diagnosis* / Q000209:etiology; D018592:Cross-Over Studies; D005500:Follow-Up Studies; D006801:Humans; D009907:Optometry / Q000379:methods*; D011379:Prognosis; D012030:Refractive Errors / Q000628:therapy; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors