Central scotoma
The peripheral visual fields are normal in both eyes. There is a right central scotoma (revealed by testing the central field with a red pin). Note: the most likely diagnosis is optic neuritis.

Further examination: 

  • Mention you like to examine the patient's fundus for any evidence of papillitis or optic atrophy. Also check for relative afferent pupillary defect.
  • If ask to perform neurological examination, look for cerebellar signs or spastic paresis which are common in patients with multiple sclerosis.