The histopathology and the mechanism of entropion in patients with trachoma.

Background: Eyelids of patients with trachoma may be thickened. This thickening could be attributed to trachomatous changes in the conjunctiva and tarsus.

Methods: Biopsies of tarsal plates and palpebral conjunctivae were obtained from 17 upper eyelids of 11 patients with inactive trachoma who underwent posterior tarsotomy procedures for entropion repair.

Results: Light microscopy studies showed a thick and compact subepithelial fibrous membrane adherent to the tarsal plate. This membrane caused apparent thickening of the tarsus when measured intraoperatively (range, 1.25-2.00 mm). Other histopathologic findings include atrophy of the meibomian glands with thickening of the acinar basement membrane, loss of goblet cells, retention cysts, and hyaline degeneration of the tarsal plate with focal replacement by adipose tissue.

Conclusion: The contraction of the subepithelial fibrous membrane formed by vertically oriented parallel collagen fibers is one of the main factors contributing to the entropion formation.