This motor response occurs within minutes of drinking coffee and can last for up to 90 minutes. There is no gender difference in the effect that coffee has on motor activity (Rao et al, 1998), but it may not be related to caffeine.
Dilation of the pupil in an eye with the synechia can cause the pupil to take an irregular, non-circular shape (Dyscoria) as shown in the photograph. If the pupil can be fully dilated during the treatment of iritis, the prognosis for recovery from synechia is good. This is a treatable status. To subdue the inflammation, use topical corticosteroids.
A pupillary response can be intentionally conditioned as a Pavlovian response to some stimuli. The latency of pupillary response (the time in which it takes to occur) increases with age. Use of central nervous system stimulant drugs and some hallucinogenic drugs can cause dilation of the pupil. In ophthalmology, intensive studies of pupillary response are conducted via videopupillometry. Anisocoria is the condition of one pupil being more dilated than the other.