Table 1. WHO classification of middle ear disorders.

Source: Smith & Mackenzie 1999[30].

Diagnosis	Features
Normal	Normal appearances of the tympanic membrane
Foreign Body	Foreign body
Cerumen Impaction	Wax plug obstructing the tympanic membrane unsuitable for removal in the field
Acute Otitis Media	Ear pain or discharge for lasting less than two weeks with a red or opaque tympanic membrane with moderate-severe bulging
Serous Otitis Media	Retracted and dull tympanic membrane
Chronic Suppurative Otitis Media	Persistent purulent discharge lasting for longer than 2 weeks in conjunction with ottorhoea in the external auditory meatus and a perforated tympanic membrane on examination.
Dry Perforation	Perforated tympanic membrane without evidence
Healed Perforation	Healed perforation of the tympanic membrane