Acquired anisocoria

Specialty: Ophthalmology.

• recently appearing pupils of different sizes
• acquired pupillary asymmetry

Why it occurs

• Acute compressive palsy of the third cranial nerve (oculomotor nerve, with ipsilateral pupillary dilation)
• Horner syndrome (interruption of the sympathetic pathway, with ipsilateral miotic pupil)
• Adie's tonic pupil (postganglionic parasympathetic denervation causing unilateral lazy mydriasis)
• Direct ocular trauma with rupture of the iris sphincter or angular recession
• Accidental pharmacological mydriasis (from rubbing the eyes after contact with plants such as Datura stramonium, scopolamine patches or ipratropium sprays)

Initial workup

Clinical assessment of the pupils under photopic and scotopic lighting conditions to identify which is the pathological pupil (the difference increases in the dark in sympathetic failures such as Horner, and increases with light in parasympathetic failures such as third nerve palsy or Adie's pupil); 0.5% apraclonidine or 4% cocaine test (for confirmation of Horner Syndrome); Pilocarpine test very diluted at 0.1% (Adie's pupil constricts due to denervation hypersensitivity); Urgent cranial CT angiography or MR angiography.

Standard management

• There are no drugs directly indicated for the ocular treatment of anisocoria of central neurological origin; Management focuses on resolving the underlying compressive, tumor, or ischemic pathology immediately in the emergency medical service.