In the grading of trachoma, follicular stage is defined as the presence of

WHO classification for Trachoma &;FISTO&;: 1. TF: Trachomatous inflammation-follicular. It is the stage of active trachoma with predominantly follicular inflammation. To diagnose this stage at least five or more follicles (each 0.5 mm or more in diameter) must be present on the upper tarsal conjunctiva. Fuher, the deep tarsal vessels should be visible through the follicles and papillae. 2. TI : Trachomatous inflammation intense. This stage is diagnosed when pronounced inflammatory thickening of the upper tarsal conjunctiva obscures more than half of the normal deep tarsal vessels. 3. TS: Trachomatous scarring. This stage is diagnosed by the presence of scarring in the tarsal conjunctiva. These scars are easily visible as white, bands or sheets (fibrosis) in the tarsal conjunctiva. 4. TT: Trachomatous trichiasis. TT is labelled when at least one eyelash rubs the eyeball. Evidence of recent removal of inturned eyelashes should also be graded as trachomatous trichiasis. 5. CO: Corneal opacity. This stage is labelled when easily visible corneal opacity is present over the pupil. This sign refers to corneal scarring that is so dense that at least pa of pupil margin is blurred when seen through the opacity. The definition is intended to detect corneal opacities that cause significant visual impairment (less than 6/18). Reference :- A K KHURANA 7th edition ; page:-66