title: The predictive value of the penlight test for photophobia for serious eye pathology in general practice.
abstract: BACKGROUND
  Photophobia has been described as a useful sign in distinguishing severe from benign eye pathology.
  
  
  OBJECTIVE
  This observational study was performed to assess the utility of the penlight test for photophobia in patients presenting with a red eye in general practice.
  
  
  METHODS
  Thirty patients presenting with a red eye to one GP in 1 year were studied. All patients were examined with a penlight flashlight for photophobia. This was followed by slit-lamp examination for diagnosis of serious or benign eye pathology.
  
  
  RESULTS
  The penlight test was positive in eight out of 10 (80%) patients with serious pathology (mainly uveitis and keratitis) and was negative in 21 out of 26 (81%) patients with less serious pathology (mainly conjunctivitis). The positive predictive value of the test was 60% and the negative predictive value was 90% (chi-squared = 7, P = 0.001, odds ratio = 17, 95% confidence interval 2-179).
  
  
  CONCLUSIONS
  The penlight test for photophobia was found to be a useful test for distinguishing serious from benign eye pathology in a general practice population.
authors.affiliation: Department of Family Medicine, Rabin Medical Centre-Beilinson Campus, Petach Tikvah, Israel 49100. yonahyaphe@hotmail.com
authors.forename: John
authors.initials: J
authors.lastname: Yaphe
authors.forename: Kulwant Singh
authors.initials: KS
authors.lastname: Pandher
mesh_terms: D003937:Diagnosis, Differential; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005194:Family Practice / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020795:Photophobia / Q000175:diagnosis* / Q000503:physiopathology; D012680:Sensitivity and Specificity