Because patients with diabetic retinopathy (DR) corneas have delayed wound healing, the expression of thymosin beta 4 (Tβ4) as a potent epithelial cell migration stimulator in DR corneas was investigated. Human DR corneas were analyzed and were found to express significantly less Tβ4 compared to normal corneas, suggesting that the use of Tβ4 may accelerate the wound-healing process in this model.