Table 2.

Definition of trachoma clinical signs

Trachoma clinical sign	Definition
Trachomatous inflammation-follicular	The presence of five or more follicles in the upper tarsal conjunctiva. Follicles are round swellings that are paler than the surrounding conjunctiva, appearing white, gray, or yellow. Follicles must be at least 0.5 mm in diameter.
Trachomatous inflammation-intense	Pronounced inflammatory thickening of the tarsal conjunctiva that obscures more than half of the normal deep tarsal vessels. The tarsal conjunctiva appears red, rough, and thickened. There are usually numerous follicles, which may be partially or totally covered by the thickened conjunctiva.
Trachomatous scarring	The presence of scarring in the tarsal conjunctiva. Scars are easily visible as white lines, bands, or sheets in the tarsal conjunctiva. They are glistening and fibrous in appearance. Scarring, especially diffuse fibrosis, may obscure the tarsal blood vessels.
Trachomatous trichiasis	At least one eyelash rubs on the eyeball. Evidence of recent removal of inturned eyelashes should also be graded as trichiasis.

Reproduced from Thylefors et al.²¹