A dramatic head CT in a patient with monocular vision loss.

An elderly woman presented to the ER with complaints of sudden right sided headache and monocular right eye vision loss. Her blood pressure on presentation was 240/110 mmHg. Her non-enhanced head CT is shown.

Non-enhanced axial head CT. Can you identify the cause of the patient’s monocular vision loss?

In this case, the patient had a retinal hemorrhage in the right eye.

Other, common causes of monocular vision loss that the neurologist might see include central retinal artery occlusion (a retinal stroke), optic neuritis, glaucoma, or optic nerve ischemia which can be due to small vessel arteritis, typically Giant Cell Arteritis (called arteritic ischemic optic neuropathy, or AION). Optic neuropathy can be due to typical vascular risk factors, which is called non-arteritic ischemic optic neuropathy (NAION).

Right retinal hemorrhage identified by the green arrow.