Miosis is a medical term for constricted pupils, referring to a condition in which the pupil of the eye becomes smaller. This can be a normal physiological response to various stimuli, such as low light levels or an increase in the release of the neurotransmitter acetylcholine. Miosis can also occur as a side effect of certain medications, such as opioids and pilocarpine, and can be a sign of certain medical conditions, such as anisocoria (unequal pupil size), Horner's syndrome (a nerve disorder affecting the eye), or an intraocular (within the eye) problem such as a painful eye or retinal detachment.

In some cases, miosis can be problematic and interfere with vision, such as when it occurs in response to bright light (photophobia) or as a side effect of certain medications. In these cases, treatment may involve adjusting the dosage or switching to a different medication.

It is important to seek medical attention if you experience persistent or unusual changes in pupil size, as this can be a sign of an underlying medical issue.

Note: This is a general description. Please take professional health advice.