Information in this question are :-Sudden loss of vision Painful ocular movement Normal fundus on ophthalmoscopyAll are seen in retrobulbar neuritis and last two features are more characteristics of retrobulbar neuritis and differentiate it from papillitis.Papillitis vs retrobulbar neuritisPapillitis and retrobulbar neuritis have almost same clinical features except :i) Painful ocular movement is more common in retrobulbar neuritis than papillis ii) Fundus is normal in retrobulbar neuritis while papillitis has characteristic fundus abnormalities.