All are true regarding optic neuritis, EXCEPT:
Optic neuritis is inflammation and demyelination of optic nerve. Electroretinogram is therefore not abnormal in optic neuritis. Ref: Parson's Diseases of the Eye, Page 114 ; Comprehensive Ophthalmology By A K Khurana, 4th Edition, Pages 294-5, 488-9
Decreased visual acuity
Decreased pupillary reflex
Abnormal electroretinogram
Abnormal visual evoked response retinogram