Generally, the cause of Adie's tonic pupil is unknown; but in some cases, it may be associated with trauma, surgery, poor blood circulation or infection. How Pupils Dilate and the Cause. The scientific term for pupils dilating is mydriasis. When a pupil gets smaller it is called miosis. Both can. Dilated Pupils Information Including Symptoms, Diagnosis, Treatment, Causes, Videos, Forums, Muscle weakness. Paralysis or inability to move a body part. Nystagmus is a condition where the eyes move rapidly and uncontrollably. They can move: side to side (horizontal nystagmus). For new uneven pupil size that is related to new double vision, eyelid droopiness or head, neck or eye pain, it is best to be evaluated in the emergency room. Red, bloodshot eyes are a common sign of marijuana intoxication, so it has become part of stoner culture to attempt to cover the problem by. Pupils dilating back and forth. It's usually done as part of a regular eye exam. By this time the dilation rate was approaching an asymptote (Fig. Cocaine causes dilated pupils because of inhibition of reuptake of norepinephrine. In high concentrations, it may cause cycloplegia, and in chronic users. Although the dilation in pupil might be small, it adds a lot of predictive strength to the cognitive load detection . The pupillary response has long been. Pupil dilation is even used by the FBI to detect deception. Now work conducted in our laboratory at the Georgia Institute of Technology.