Anisocoria with a Constricted Pupil in the Affected Eye

Anisocoria with a Constricted Pupil in the Affected Eye

Horner’s Syndrome

Causes: 

Damage to the sympathetic pathway.

❖ Central (first neuron):

–  Tumors.

–  Encephalitis.

–  Diffuse encephalitis.

❖ Peripheral (second neuron):

–  Syringomyelia.

–  Diffuse encephalitis.

–  Trauma.

–  Rhinopharyngeal tumors.

–  Goiter.

–  Aneurysm.

–  Processes in the tip of the lung.

❖ Peripheral in the strict sense (third neuron):

–  Vascular processes.

–  Internal carotid aneurysm.

Clinical Picture:

❖ Miosis (approximately 1 – 2 mm difference) due to failure of the dilator pupillae muscle.

❖ Ptosis (approximately 1 – 2 mm difference) due to failure of the muscle of Müller.

❖ Enophthalmos due to failure of the rudimentary lower eyelid retractors. This makes the lower eyelid project so that the eye appears smaller. This condition only represents a type of pseudoenophthalmos.

❖ Decreased sweat gland secretion (only present in preganglionic disorders as the sweat glands receive their neural supply via the eternal carotid).

Diagnostic considerations:

❖ Direct and consensual light reflexes are intact, which distinguishes this disorder from a parasympathetic lesion); the pupil dilates more slowly (dilation deficit).

❖Near reflex is intact.

❖ Pharmacologic testing with cocaine eyedrops:

– Peripheral Horner’s syndrome:On the affected side, there is slight mydriasis (decrease in norepinephrine due to nerve lesion). On theunaffected side, there is significant mydriasis.

– Central Horner’s syndrome:On the affected side, the pupil is dilated. Onthe unaffected side, the pupil is also dilated (the norepinephrine in thesynapses is not inhibited).

Following Eyedrop Application (Unilateral Administration of a Miotic as in Glaucoma Therapy)