KRT1 and keratoconus: In humans, the keratin type II cytoskeletal 1 was downregulated in the tear samples of patients with keratoconus, a progressive thinning of the cornea giving rise to a cone-shaped cornea, instead of the normal elliptical shape [36] but this protein was not significantly upregulated in the disease status of Sjögern patients with dry eye syndrome [37,38].