All are known to produce parenchymatous conjunctival xerosis except

Xerosis of conjunctiva Depending upon the etiology, conjunctival xerosis can be divided into two groups, parenchymatous and epithelial xerosis. 1. Parenchymatous xerosis: It occurs following cicatricial disorganization of the conjunctiva due to local causes which can be in the form of (i) widespread destructive interstitial conjunctivitis as seen in trachoma, diptheric membranous conjunctivitis, Steven-Johnsons syndrome, pemphigus or pemphigoid conjunctivitis, thermal, chemical or radiational burns of conjunctiva, (ii) exposure of conjunctiva to air as seen in marked degree of proptosis, facial palsy, ectropion, lack of blinking (as in coma), and lagophthalmos due to symblepharon. 2. Epithelial xerosis: It occurs due to hypovitaminosis -A. Epithelial xerosis may be seen in association with night blindness or as a pa and parcel of the xerophthalmia (the term which is applied to all ocular manifestations of vitamin A deficiency which range from night blindness to keratomalacia. Epithelial xerosis typically occurs in children and is characterized by varying degree of conjunctival thickening, wrinkling and pigmentatiion. Reference :- A K KHURANA 7th ed; page:-84