A patient from a trachoma-endemic region has corneal pannus superiorly and superior tarsal conjunctival follicles. Herbert's pits (limbal follicle scars) are present. According to WHO trachoma grading (FISTO), which stage does this represent?
- A TS (trachomatous scarring) ✓
- B TF (trachomatous inflammation, follicular)
- C TI (trachomatous inflammation, intense)
- D CO (corneal opacity)
Correct answer: A. TS (trachomatous scarring)
Explanation
Herbert's pits are pathognomonic scars at the limbus resulting from healed follicles of active trachoma (Chlamydia trachomatis serotypes A, B, Ba, C). Their presence indicates progression to trachomatous scarring (TS stage on the WHO simplified grading scale), signifying chronic conjunctival damage that can eventually cause trichiasis (TT stage) and corneal opacity (CO stage). Active follicular trachoma (TF/TI) in the community is treated with the SAFE strategy—Surgery, Antibiotics (azithromycin), Facial cleanliness, Environmental improvement.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.