Objective and importance: Compression of the optic nerve by a dolichoectatic internal carotid artery is a rare and correctable cause of visual loss.
Clinical presentation: A young woman presented with right eye visual loss without obvious cause and was found to have compression of the right optic nerve by the ipsilateral internal carotid artery, as revealed by magnetic resonance imaging.
Intervention: Pterional craniotomy and decompression of the optic nerve by unroofing the optic canal resulted in improvement of vision in the affected eye.
Conclusion: Compression of the optic nerve by a dolichoectatic internal carotid artery may produce visual loss. The disorder is well demonstrated by magnetic resonance imaging, and timely intervention can improve vision.