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Chapter: Ophthalmology: Pupil

Anisocoria with Dilated Pupil in the Affected Eye

Processes in the base of the skull such as tumors, aneurysms, inflamma-tion, or bleeding.

Anisocoria with Dilated Pupil in the Affected Eye


Complete Oculomotor Palsy

Causes:

Processes in the base of the skull such as tumors, aneurysms, inflamma-tion, or bleeding.

Diagnostic considerations:

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.

Tonic Pupil

Causes: 

Postganglionic damage to the parasympathetic pathway, pre-sumably in the ciliary ganglion, that frequently occurs with diabetes mellitus, alcoholism, viral infection, and trauma.

Diagnostic considerations:

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.

 

Iris Defects

Causes:

  Trauma (aniridia or sphincter tears).

Secondary to acute angle closure glaucoma.

Synechiae (post-iritis or postoperative).

Diagnostic considerations: 

Patient history and slit-lamp examination.

Following Eyedrop Application (Unilateral Administration of a Mydriatic)

Simple anisocoria

Causes: 

Presumably due to asymmetrical supranuclear inhibition of theEdinger-Westphal nucleus.

Diagnostic considerations:

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.

 

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Ophthalmology: Pupil : Anisocoria with Dilated Pupil in the Affected Eye |


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