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Patients whose eyes have suffered heat or chemical burns typically experience severe damage to the cornea—the thin, transparent front of the eye that refracts light and contributes most of the eye's focusing ability. In a long-term study, Italian researchers use stem cells taken from the limbus, the border between the cornea and the white of the eye, to cultivate a graft of healthy cells in a lab to help restore vision in eyes. During the 10-years study, the researchers implanted the healthy stem cells into the damaged cornea in 113 eyes of 112 patients. The treatment was fully successful in more than 75 percent of the patients, and partially successful in 13 percent. Moreover, the restored vision remained stable over 10 years. Success was defined as an absence of all symptoms and permanent restoration of the cornea. Treatment outcome was initially assessed at one year, with up to 10 years of follow-up evaluations. The procedure was even successful in several patients whose burn injuries had occurred years earlier and who had already undergone surgery. Current treatment for burned eyes involves taking stem cells from a patient's healthy eye, or from the eyes of another person, and transferring them to the burned eye. The new procedure, however, stimulates the limbal stem cells from the patient's own eye to reproduce in a lab culture. Several types of treatments using stem cells have proven successful in restoring vision, but the long-term effectiveness shown here is significant. The treatment is only for blindness caused by damage to the cornea; it is not effective for repairing damaged retinas or optic nerves. Chemical eye burns often occur in the workplace, but can also happen due to mishaps involving household cleaning products and automobile batteries. The results of the study, based at Italy's University of Modena and Reggio Emilia, were published in the June 23 online issue of the New England Journal of Medicine.