The reduction in activities is associated with higher KC stages.[9] A diminution in the activity of superoxide dismutase (SOD) and glutathione has been detected in the blood of individuals diagnosed with KC, accompanied by increased levels of CAT.[10] As a nonenzymatic molecule antioxidant, uric acid (UA) is found to be elevated in the tear film of KC patients, implying its possibility as a risk factor.[11] Interestingly, vitamin C levels appear to rise in KC corneas,[12] indicating an adaptive reaction to OS and compromised collagen production. This evidence concerns the gene CAT and keratoconus.