We conducted a two-part study to define better the clinical predictors of scleral rupture after blunt trauma. In part 1 we ascertained the prevalence of scleral rupture among a population of patients examined in an ophthalmic emergency room with severe blunt ocular trauma over a six-month period. Scleral rupture was diagnosed in ten of 283 patients (3.5%). In part 2 we compared the clinical findings in 29 patients with scleral rupture to those of 273 patients with no scleral rupture after blunt trauma. We noted that eyes with visual acuity of light perception or less, an intraocular pressure of 5 mm Hg or less, an abnormally deep or shallow anterior chamber, or a media opacity preventing a view of fundus details by indirect ophthalmoscopy, should be considered ruptured when severe intra- or periocular hemorrhage is present. This diagnostic algorithm had a sensitivity of 100.0% (98.7% to 100.0%), specificity of 98.5% (97.1% to 99.9%), and a positive predictive value of 71.4% (66.3% to 76.5%).