The Role of Umbilical Cord Serum Therapy on Improvement of Corneal Epithelial Defect Following Diabetic Vitrectomy

80 diabetic patients underwent vitrectomy and had no history of Eye herpes infection, Refractive surgery, Autoimmune disease, Immune deficiency will be randomized into two groups (double blind)to evaluate the role of umbilical cord serum therapy on improvement of corneal epithelial defect following diabetic vitrectomy. Both groups will take the conventional medication including Chloramphenicol, Betamethasone, Cycloplegic eye drops besides the case group will take umbilical cord serum eye drop in the eye operated. After surgery the corneal epithelial defect will be measured by slit lamp.