Isocoria with Constricted Pupils

Isocoria with Constricted Pupils

Argyll-Robertson Pupil

Causes: 

The precise location of the lesion is not known; presumably the dis-order is due to a lesion is in the pretectal region and the Edinger-Westphal nucleus such as tabes dorsalis (Argyll-Robertson phenomenon), encephalitis, diffuse encephalitis, syringomyelia, trauma, bleeding, tumors, and alco-holism.

Diagnostic considerations:

❖ Direct and consensual light reflexes are absent.

❖Near reflex is intact or there is overcompensation (the Edinger-Westphal nucleus is being controlled via the convergence center).

❖The pupil is not round, and constriction is not always symmetrical.

❖There is no reaction to darkness or pharmacologic stimuli.

Bilateral Pupillary Constriction due to Pharmacologic Agents

Causes:

❖ Morphine.

❖Deep general anesthesia.

❖ Pilocarpine eyedrops.

Toxic Bilateral Pupillary Constriction

Causes: 

Mushroom poisoning.

Inflammatory Bilateral Pupillary Constriction

Causes:

❖ Encephalitis.

❖ Meningitis.