Anisocoria with Dilated Pupil in the Affected Eye
❖ Processes in the base of the skull such as tumors, aneurysms, inflamma-tion, or bleeding.
❖ Direct and consensual light reflexes without constriction in the affected eye (fixed pupil).
❖Near reflex miosis is absent.
❖ Impaired motility and double vision.
Sudden complete oculomotor palsy (loss of motor and parasympa-thetic function) is a sign of a potentially life-threatening disorder. In unconscious patients, unilateral mydriasis is often the only clinical sign of this.
Postganglionic damage to the parasympathetic pathway, pre-sumably in the ciliary ganglion, that frequently occurs with diabetes mellitus, alcoholism, viral infection, and trauma.
❖ Direct and consensual light reflexes show absent or delayed reaction, possibly with worm-like segmental muscular contractions.
❖ Dilation is also significantly delayed.
❖Near reflex is slow but clearly present; accommodation with delayed relaxation is present.
❖ Motility is unimpaired.
❖ Pharmacologic testing with 0.1% pilocarpine.
– Significant miosis in the affected eye (denervation hypersensitivity).
– No change in the pupil of the unaffected eye (too weak).
❖ Adie’s tonic pupil syndrome: The tonic pupil is accompanied by absence of the Achilles and patellar tendon reflexes.
Tonic pupil is a relatively frequent and completely harmless cause of unilateral mydriasis.
❖ Trauma (aniridia or sphincter tears).
❖Secondary to acute angle closure glaucoma.
❖ Synechiae (post-iritis or postoperative).
Patient history and slit-lamp examination.
Presumably due to asymmetrical supranuclear inhibition of theEdinger-Westphal nucleus.
❖ Direct and consensual light reflexes and swinging flashlight test show con-stant difference in pupil size.
❖Near reflex is normal.
❖ Pharmacologic testing: Cocaine test (4% cocaine eyedrops are applied to both eyes and pupil size is measured after one hour): bilateral pupil dila-tion indicates an intact neuron chain.