In established trachoma (caused by caused by C trachomatis serovars A, B, Ba, or C), there may also be superior epithelial keratitis, subepithelial keratitis, pannus, or superior limbal follicles, and ultimately the pathognomonic cicatricial remains of these follicles, known as Herbe's pits--small depressions covered by epithelium at the limbocorneal junction. Ref: Nijm L.M., Garcia-Ferrer F.J., Schwab I.R., Augsburger J.J., Correa Z.M. (2011). Chapter 5. Conjunctiva & Tears. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.