VEGFA and keratoconus: Consequently, KC is predominantly employed in the study of vascular diseases such as retinal vascular diseases, cardiovascular diseases, pulmonary hypertension, etc. To the best of our knowledge, few works have been reported on the utilization of KC to impede the HIF/VEGF pathway for alleviating tumor hypoxia endogenously and reversing oxidative resistance in tumors to enhance PDT efficacy [43,44].