The police often use pepper spray so that the culprit becomes blind temporarily.
Pepper spray, unlike teargas, is not an irritant, it is an inflammatory agent.
When a person is sprayed with pepper spray their eyes clamp shut, if they manage to open them they most likely will not see anything because the capillaries in their eyes will be dilated, causing temporary blindness.
There may also be an uncontrollable fit of coughing which doubles the person over, bringing them down to their knees.
