Anisocoria

Anisocoria is a difference between the right and left pupil sizes greater than 0.3 mm. Physiological anisocoria up to 1 mm occurs in 20% of the population. Pathological anisocoria can be caused by eg. unilateral irritation or lesions of the parasympathetic or sympathetic nervous system (Horner's syndrome), unilateral increase of intraocular pressure (glaucoma), aneurysm, tumor, trauma, intracranial hemorrhage (epidural and subdural), multiple sclerosis, unilateral blindness, unilateral application of mydriatics/miotics, etc.