Keratinization of the bulbar conjunctival epithelium in superior limbic keratoconjunctivitis in humans. An electron microscopic study.

A prominent histological feature of superior limbic keratoconjunctivitis is the presence of keratinization of the superior bulbar conjunctiva. Ultrastructurally the affected conjunctival epithelium shows all of the characteristics of keratinization as described in skin. There is a superficial layer of horny cells with reduced organelles and thickened cell membrane. In the intermediate layers, the cells contain an increased number of cytoplasmic filaments which are sometimes aggregated into dense masses, keratohyalin granules, both in the cytoplasm and in the nucleus, membrane coating granules, lysosomes and various other types of membranous structures.