A 30-year-old woman is brought to emergency because of gradual diminishing vision in her left eye since awakening 6 hours ago. Her symptoms began with a mild headache over the left eye before going to sleep last night. Fundoscopic examination shows no abnormalities, however she cannot read text and cannot count fingers with the left eye. Visual acuity in the right eye is normal. Which of the following is the most likely diagnosis?
Cluster headache
Embolus
Optic glioma
Optic neuritis
Temporal arteritis
