Quantitative analysis of metabolite levels identified by targeted LC-MS/MS in corneal cell lysates isolated from healthy controls (HCFs) and keratoconus patients (HKCs), revealing the effects of CXL on glucose metabolism and citric acid cycle metabolites. a Lactate, b ATP, c orotate, d adenosine, e dAMP, f hexose phosphate, and g glucose 6-phosphate. n = 4, *p < 0.05, **p < 0.01, ****p < 0.0001