Bedside Diagnosis of the 'Red Eye': A Systematic Review

In patients with red eye, traditional teachings suggest that photophobia, visual blurring, and eye pain indicate serious eye disease; in patients with presumed conjunctivitis, the finding of purulent drainage traditionally indicates a bacterial cause. The accuracy of these teachings is unknown.

A MEDLINE search was performed to retrieve articles published between 1966 and April 2014 relevant to the bedside diagnosis of serious eye disease and bacterial conjunctivitis.

In patients with red eye, the most useful findings indicating serious eye disease are anisocoria (with the smaller pupil in the red eye and difference between pupil diameters >1 mm; likelihood ratio [LR], 6.5; 95% confidence interval [CI], 2.6-16.3) and photophobia, elicited by direct illumination (LR, 8.3; 95% CI, 2.7-25.9), indirect illumination (LR, 28.8; 95% CI, 1.8-459), or near synkinesis test ("finger-to-nose convergence test," LR, 21.4; 95% CI, 12-38.2). In patients with presumed conjunctivitis, complete redness of the conjunctival membrane obscuring tarsal vessels (LR, 4.6; 95% CI, 1.2-17.1), observed purulent discharge (LR, 3.9; 95% CI, 1.7-9.1), and matting of both eyes in the morning (LR, 3.6; 95% CI, 1.9-6.5) increase the probability of a bacterial cause; failure to observe a red eye at 20 feet (LR, 0.2; 95% CI, 0-0.8) and absence of morning gluing of either eye (LR, 0.3; 95% CI, 0.1-0.8) decrease the probability of a bacterial cause.

Several bedside findings accurately distinguish serious from benign eye disease in patients with red eye and, in patients with presumed conjunctivitis, distinguish bacterial from viral or allergic causes.