All are true regarding optic neuritis, EXCEPT:
Decreased visual acuity
Decreased pupillary reflex
Abnormal electroretinogram
Abnormal visual evoked response retinogram
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