<prompt> Blue eardrum is seen inSerous otitis mediaCSOMPerforationNone  <response>: Serous otitis media is an insidious condition characterized by an accumulation of nonpurulent effusion in the middle ear cleft. In otoscopy, the tympanic membrane is often dull and opaque with loss of the light reflex. It may appear yellow, grey or bluish in colour. Reference: Diseases of Ear, Nose and Throat, PL Dhingra, Shruthi Dhingra,7th edition, pg no.69 