The tympanic membrane is recognised by examining the ear with an instrument called an otoscope. It has a bright light, attached speculum and magnifying lens that allow the trained eye of your doctor or ENT surgeon to recognise the structures deeper in the ear canal. A normal ear drum gives off a reflection of light called the light reflex. If the drum or middle ear is abnormal, most commonly due to middle ear fluid or infection, the light reflex is lost and the ear drum appears dull. Of course there are other causes of loss of the light reflex (including flat batteries in the otoscope!) that need to be excluded before diagnosing the ear drum appearance as abnormal. Generally a few weeks after the middle ear condition has resolved, the drum resumes its normal shiny appearance and the light reflex returns.