Objective:

Highlight a rare ischemic phenomenon seen with posterior circulation lesions.

Background:

Posterior cerebral artery strokes are uncommon and may be overlooked when visual symptoms are subtle. Infarction in this territory usually causes hemianopia or reading difficulty, but some patients develop higher‑order visual disturbances such as achromatopsia. Achromatopsia is complete loss of color perception and may be congenital or acquired. Color information is processed in a network extending from retinal cones through the lateral geniculate nucleus and primary visual cortex to the V4 area in the ventral occipitotemporal cortex. Bilateral injury to this network disrupts cortical color processing while sparing luminance perception, resulting in achromatopsia. Associated agnosia and anomia suggest involvement of adjacent temporal regions responsible for object identification and language. We describe a patient with acquired achromatopsia, color agnosia, and anomia after bilateral occipitotemporal infarcts.

Design/Methods:

Single patient retrospective chart review.

Results:

A 68‑year‑old man with history of atrial fibrillation presented with concerns of visual changes. He perceived the world only in shades of grey and struggled to name familiar objects. Neurologic examination was otherwise unremarkable. Formal ophthalmologic examination, including dilated fundus evaluation, was normal with no intraocular pathology. Non-contrast CT showed bilateral low attenuation lesions in the posterior temporal and occipital lobes, consistent with subacute posterior cerebral artery infarcts. He received antiplatelet therapy followed by anticoagulation after hemorrhage was excluded. By discharge his naming and recognition deficits had resolved, but loss of color vision persisted at follow-up. Unlike most reported cases, this patient had no visual field loss; achromatopsia can therefore be present in isolation.

Conclusions:

Cerebral achromatopsia is a rare but distinct manifestation of posterior cerebral artery stroke. Sudden loss of color vision, with or without color agnosia or anomia, should raise suspicion for bilateral occipital injury and prompt neuroimaging to guide timely management.