Given that gel-forming mucins lubricate the ocular surface while trapping the debris or pathogens from the outside environment from binding to the epithelial cells [34, 35], the reduced MUC5AC secretion caused by TcES may increase the vulnerability of the ocular surface to pathogens in addition to contributing to dry eye. The gene discussed is MUC5AC; the disease is Keratoconjunctivitis sicca.