Clinical effects of oleoresin capsicum (pepper spray) on the human cornea and conjunctiva

Objective: To evaluate the effects of oleoresin capsicum (OC) on the human cornea and conjunctiva and to test the effectiveness of topical anesthetics for relief of pain. Design: Prospective, randomized clinical trial. Methods: Forty-seven subjects were examined before and at 10 minutes and 1 hour after exposure to pepper spray during a training exercise. Eleven subj ects were reexamined at I week after exposure. A short, subjective question naire was given asking subjects to rate their pain, blurring of vision, and tearing. After exposure, subjects were randomly given a placebo, a topical nonsteroidal antiinflammatory agent, or a topical anesthetic. Main Outcome Measures: Visual acuity and corneal sensitivity with a Cochet- Bonnet aesthesiometer (scale of 1-6 cm) was measured and the eyes were exam ined with a portable slit lamp using fluorescein. Symptoms of pain, blurrin g of vision, and tearing were recorded in a ranking of 0 to 10. Results: Visual acuity was unaffected by exposure to pepper spray. Corneal sensitivity was reduced from a pretest mean of 5.7 cm to a posttest mean of 0.6 cm 10 minutes after exposure. At 1 hour, the mean corneal sensitivity had recovered-to 2.9 cm. Twenty-one percent of eyes had evidence of punctat e epithelial erosions, but no corneal abrasions were found. Alt subjects re ported significant pain, blurring of vision, and tearing at 10 minutes that was much improved by 1 hour. Topical flurbiprofen 0.03% improved symptoms in two of 11 subjects, whereas topical proparacaine hydrochloride 0.5% impr oved symptoms in 16 of 29 eyes. At I week after exposure, corneal sensation returned to baseline, and no corneal abnormalities were noted. Conclusions: The predominant symptom after exposure to OC was pain. Topical flurbiprofen was not helpful in reducing symptoms of exposure, whereas top ical proparacaine was effective in relieving pain in most subjects. Corneal sensitivity was dramatically reduced at 10 minutes after exposure and was improved after 1 hour. At 1 week, corneal sensation had returned to normal, as had slit-lamp appearance on all subjects examined. (C) 2000 by the Amer ican Academy of Ophthalmology.