In some ocular surface inflammatory diseases, such as dry eye and pterygium, ICAM-1 was found to be upregulated on lymphocytes and/or vascular endothelial cells resulting in lymphocytic diapedesis to the lacrimal and conjunctival tissues, and may serve as a signaling molecule for predisposition of ocular surface inflammation [46,47]. This evidence concerns the gene ICAM1 and Keratoconjunctivitis sicca.