Pharmacologic Mydriasis

What is it?

Dilated (mydriatic) pupil attributed to topical contamination with an anticholinergic or strong sympathomimetic (adrenergic) agent
Tip: topically-applied anticholinergic agents cause considerable mydriasis and impaired accommodation whereas systemically-administered anticholinergic agents do not cause much mydriasis yet they impair accommodation
Common causes: eyedrops, scopolamine patch, aerosols in ventilator regimens
Uncommon causes: atropinic vegetable substances, glycopyrrolate cream for hyperhidrosis, nasal decongestants

Dilated pupil in one eye or both eyes with reduced or absent constriction to light
Impaired accommodation in the affected eye(s) among patients aged less than 45 years because of anticholinergic-induced paralysis of the ciliary muscle

Elicit a history of exposure to topical contaminants
Assess accommodation in young patients, looking for an expected reduction in the affected eye (with anti-cholinergic contamination, but not with sympathomimetic contamination)
Note absence of other pertinent abnormalities
Instill pilocarpine 1% in both eyes, wait 30 minutes, and confirm that the affected pupil has not constricted or has constricted much less than the unaffected pupil
Tip: orally or parenterally administered medications with anticholinergic properties do not cause anisocoria and uncommonly cause mydriasis
Tip: looking for reduced accommodation is useful in diagnosing pharmacologic mydriasis in young patients, as it almost excludes tonic (Adie) pupil and non-pharmacologic episodic (dysautonomic) mydriasis, but…
Trap: accommodation will be preserved if mydriasis is caused by a powerful sympathomimetic agent

When the offending agent is discontinued, the affected pupil returns to normal size and constricts normally to light within hours to days