CKB and proliferative diabetic retinopathy: In human vitreous proteome of patients with proliferative diabetic retinopathy, a decrease in the amount of α‐crystallin A, β‐crystallin S (Crygs), tubulin β and creatin kinase B was observed 41 suggesting the possible implication of these proteins in the proliferative conditions; however, it is not known if their reduced level is the cause or the consequence of the proliferative state.