Which structure is most likely involved in the acute bilateral blindness after a prolonged surgery in a morbidly obese patient who became hypotensive during a 6-hour procedure?

Which structure is most likely involved in the acute bilateral blindness after a prolonged surgery in a morbidly obese patient who became hypotensive during a 6-hour procedure?

• A. Central retinal artery
• B. Optic nerve
• C. Retina
• D. Cerebral cortex

Answer: (B)

The scenario points to ischemic injury of the optic nerve due to prolonged systemic hypotension during a long surgery. The optic nerve head is particularly vulnerable when mean arterial pressure drops, because its blood supply from the short posterior ciliary arteries can’t be fully preserved by autoregulation for extended periods. This can cause ischemic optic neuropathy, leading to sudden, bilateral blindness in a high‑risk patient like a morbidly obese individual undergoing a lengthy procedure. Think of the alternatives in context: central retinal artery occlusion would typically cause abrupt, usually unilateral vision loss with specific retinal signs, not bilateral blindness after a single surgery. The retina itself isn’t the primary problem here given the systemic hypotension and the bilateral nature. Cortical blindness from occipital lobe injury would usually accompany other neurologic deficits and often preserve the pupillary light reflex, which doesn’t fit this anesthetic scenario as well as optic nerve injury does.

The scenario points to ischemic injury of the optic nerve due to prolonged systemic hypotension during a long surgery. The optic nerve head is particularly vulnerable when mean arterial pressure drops, because its blood supply from the short posterior ciliary arteries can’t be fully preserved by autoregulation for extended periods. This can cause ischemic optic neuropathy, leading to sudden, bilateral blindness in a high‑risk patient like a morbidly obese individual undergoing a lengthy procedure.

Think of the alternatives in context: central retinal artery occlusion would typically cause abrupt, usually unilateral vision loss with specific retinal signs, not bilateral blindness after a single surgery. The retina itself isn’t the primary problem here given the systemic hypotension and the bilateral nature. Cortical blindness from occipital lobe injury would usually accompany other neurologic deficits and often preserve the pupillary light reflex, which doesn’t fit this anesthetic scenario as well as optic nerve injury does.