Anisocoria Secondary to Anticholinergic Mydriasis from Homeopathic Pink Eye Relief Drops

A woman, aged 70 years, developed anisocoria after applying homeopathic eye drops (Similasan Pink Eye Relief) to her left eye. Her pupil was dilated for two weeks and did not respond to light or near stimuli for one week. Both 0.1% and 1% pilocarpine failed to constrict her left pupil, and magnetic resonance imaging of her brain did not reveal any abnormality. The eye drops she had used contain belladonna extracts which have a natural atropine component. This case demonstrates the importance, when evaluating a patient presenting with anisocoria, of knowing the chemical ingredients of the homeopathic eye drops, which often are not listed.