When Pupils Don’t Follow the Light

Discover the cause of a unique pupillary exam finding in a patient with a midbrain lesion, Diplopia, and headache. Learn about this key neurological sign.

Light-near dissociation


A 37-year-old man presented to the neurosurgery clinic with blurry vision, headache, and difficulty looking upward. On exam, he had diplopia, upward gaze palsy, and vertical misalignment of the eyes. His pupils only minimally constricted to light but constricted to near objects. What is the name of this pupillary exam finding?

What is the most likely diagnosis?

Adie’s pupil
Anisocoria
Argyll Robertson pupil
Light-near dissociation
Relative afferent pupillary defect (e.g., Marcus Gunn pupil)

Dorsal Midbrain Syndrome, Germinoma, Light-near dissociation, Parinaud Syndrome, Pupillary Reflex

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