Trachoma staging by the WHO simplified grading system (1987): 'Trachomatous Trichiasis (TT)' refers to:

• A Follicles on the upper tarsal conjunctiva only
• B At least one eyelash rubbing on the eyeball, or evidence of recent epilation ✓
• C Corneal scarring with opacity affecting the visual axis
• D Intense diffuse conjunctival inflammation obscuring deep tarsal vessels

Explanation

The WHO simplified trachoma grading (MacCallan modification, 1987) defines 5 grades: TF (follicular inflammation), TI (intense inflammation), TS (tarsal scarring), TT (trichiasis: at least one lash touching the globe or evidence of recent epilation), and CO (corneal opacity). TT is the stage requiring surgical intervention (bilamellar tarsal rotation or other lid surgery) to prevent further corneal scarring. CO indicates corneal opacification involving the pupillary zone causing significant visual impairment. Trachoma remains the leading infectious cause of blindness globally, caused by Chlamydia trachomatis serovars A, B, Ba, and C.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.