ANISOCORIA

(unequal pupil size)

essential (congenital) anisocoria

Horner's syndrome [+ ptosis + enophthalmos + anhidrosis on same side]

Holmes-Aide syndrome [myotonic pupil; dilated pupil reacting sluggishly to light ± accommodation; + loss of deep tendon reflexes]

Argyll-Robertson pupil [usually bilateral and due to tertiary syphilis; small, irregular pupil reacting to accommodation but not to light]

complete 3rd nerve palsy [eye in 'down and out' position due to ophthalmoplegia; also severe ptosis]

midbrain lesions [depressed pupillary reflexes; other neurological signs]

infections:

botulism

local causes:

acute glaucoma [fixed, dilated pupil; cloudy cornea + painful eye]

unilateral iritis or keratitis [miosis ± synechiae], including herpes zoster

prosthetic eyeball