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.

Inclusion Criteria:

• Diabetic patients with corneal epithelial defect following diabetic vitrectomy at labbafinejad Hospital

Exclusion Criteria:

• Any history of Eye herpes infection, Refractive surgery, Autoimmune disease, Immune deficiency
• Patients with one eye
• Use of any eye drops except Chloramphenicol, Betamethasone, Cycloplegic and contact lens for corneal epithelial defect