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). Conclusion. The penlight test for photophobia was found to be a useful test for distinguishing serious from benign eye pathology in a general practice population.