<prompt> The sign of retrobulbar neuritis is -Optic atrophyPapilledemaCircumciliary congestionImpairment of color vision  <response>: Ans- D Optic Neuritis A. Papilitis Most common causes : Multiple sclerosis. Ophthalmoscopic features: Swollen optic disc up to 2 D Hyperemic disc. Disc margins blurred. Clinical feature Usually UL Sudden loss of vision. Pain on eye movement retrobulbar neuritis Marcus gunn pupil or RAPD Relative Afferent Pupillary Defect Centrocaecal scotomas. Impairment of color vision Uthoff sign-worsening of vision with increase in body temperature Pulfrich phenomenon-Abnormal depth perception oscillating object seems to move in elliptical direction Treatment ONTT TRIAL 1ST three days iv methyl prednisofone Followed by tapering dose of oral Prednisolone over 11 days. Total 31114 days Investigation of choice : MRI orbits Brain T2W with contrast Retrobulbar neuritisInvolvement of retro laminar part of optic nerve. Ophthalmoscopic feature-Normal optic nerve head and retinal nerve fibre layer. SS- Similar to papillitis. Neuroretinitis Disc edema and Macular star. 