Walsh & Hoyt: Pharmacologic Testing

A few cautionary comments should be made regarding the interpretation of pupillary responses to topically instilled drugs. First, the test variables must be carefully controlled whenever possible, both before and after pharmacologic testing. This means that the ambient lighting should be optimal for the test performed, the patient must fixate in the distance for at least 1 minute to minimize miosis and relax the pupil, and the patient should be alert throughout the test, because the psychic state of the individual can influence pupillary size (e.g., the pupils tend to be miotic in persons who are tired or listless and mydriatic in patients who are upset or anxious).