mydriáza

Mydriasis refers to the dilation of the pupil of the eye. The pupil is the opening in the center of the iris that allows light to enter the retina. Normally, the size of the pupil is controlled by the iris muscles, which constrict the pupil in bright light to reduce the amount of light entering the eye and dilate it in dim light to allow more light in. Mydriasis occurs when the pupil becomes abnormally large.

This condition can be caused by a variety of factors. Physiologically, mydriasis can occur naturally in response to fear, excitement, or pain, as part of the body's "fight or flight" response. Certain medications, such as atropine, scopolamine, and some sympathomimetic drugs, can also induce mydriasis by affecting the nerves that control the iris muscles. Ocular trauma or certain neurological conditions affecting the cranial nerves, particularly the oculomotor nerve, can also lead to pupillary dilation. In some cases, mydriasis can be a symptom of a more serious underlying medical issue, such as a brain aneurysm or stroke.

Mydriasis itself is not a disease but rather a sign. The significance of mydriasis depends on its cause. If it is a physiological response to stimuli, it is temporary and harmless. However, if it is caused by medication, trauma, or a neurological event, it requires medical attention to diagnose and treat the underlying cause. A doctor will typically examine the eyes and assess other symptoms to determine the reason for the dilated pupil. Treatment will vary depending on the etiology.