mydriasis
Pronunciation: mid-RYE-ah-sis
Abnormal dilation of the pupil that may be pharmacological, neurological, or pathological in origin.
Full Definition
Mydriasis refers to abnormal pupil dilation that can result from various causes including pharmacological agents, neurological lesions, or ocular pathology. In neuro-ophthalmology, pathological mydriasis often indicates third cranial nerve dysfunction, particularly when associated with ptosis and ophthalmoplegia. Adie's tonic pupil is a common cause of unilateral mydriasis with slow, tonic reactions to light and accommodation. Pharmacological mydriasis can result from anticholinergic medications or topical agents. The response to pharmacological testing helps differentiate between neurological and pharmacological causes.
Usage
Usage note: Document whether mydriasis is unilateral or bilateral and any associated neurological signs.
In Context
- "The patient presented with acute mydriasis and complete ptosis, concerning for third nerve palsy." — Emergency examination
- "Pharmacological testing confirmed that the mydriasis was due to inadvertent topical anticholinergic exposure." — Diagnostic workup report