NOS2 and keratoconus: In untreated KC-HCFs, NF-κB (p = 0.0002), iNOS (p = 0.0019), Col 1 (p = 0.0286), and Col 5 (p = 0.0054) mRNA expression was higher and IL-6 expression was lower (p = 0.0057), than in healthy controls.