Left eye at presentation. (A) Fundoscopy reveals swelling of the left optic disc. (B) Reduced peripheral sensitivity detected in a visual field test. (C) OCT quantifying the oedema in the left optic disc. Note the RNFL thickening in all quadrants and in 11 of 12 RNFL sectors. (D) Audiometry of the left ear indicating impaired sound transmission both through the air and bone. The greater effects observed for the higher frequencies are diagnostic of sensorineural deafness.