Visual impairment after exposition to oleoresin capsicum pepper spray

Oleoresin capsicum (OC) or pepper spray, is widely used as a riot control agent. It is generally seen as being safe and effective. However, one of the main effects, namely blurring of vision, may be relevant for the judicial appraisal of eyewitness accounts of persons exposed to OC. In order to quantify the impairment of vision and its duration, we examined the visual acuity of 25 police cadets before, directly after and 30 min after exposure to a jet of OC in the eyes using a Snellen chart. The mean visual acuity of the test persons before exposure was 1.18 (SD 0.4), 0.15 (SD 0.14) directly after and 1.01 (SD 0.38) 30 min after exposure. Owing to blepharospasm, eleven test persons or 44% could not open their eyes at all, and 88% of the test persons had a visual acuity of ≤ 0.3. This remarkable loss of visual acuity was only short-lived; after 30 min, almost all test persons had recuperated fully and the visual acuity did not differ significantly to that determined before exposure. Our results indicate that eyewitness accounts provided by persons exposed to OC in the eyes should be treated with caution and that a reliable detailed visual description immediately after exposure is very unlikely and that the visual impairment is rapidly fully reversible.