This study was approved by the institutional review board of Hangzhou First People’s Hospital, China. Prior informed consent was obtained from all patients. The study included seven eyes from seven different patients with unilateral LSCD who underwent autologous COMET at our hospital from April 2013 to October 2015. Patient 1 had an acute thermal burn and a 2-month-old corneal epithelial defect. Patient 2 had recurrent pterygium. The other five patients had chronic burns that were covered by a fibrovascular ingrowth from the limbus over the central cornea and symblepharon.
Cultivation of oral mucosal epithelial sheets
A 10-by-10-mm oral mucosal biopsy was performed on each patient under local anesthesia. Oral mucosal epithelium was then incubated at 4 °C for 5 h with dispase II (1.25 mg/mL), followed by treatment with trypsin-EDTA for 10 min to create a single-cell suspension. The single-cell suspension was then incubated with oral keratinocyte medium on an amniotic membrane for 2 weeks.
Cryosections were stained with hematoxylin and eosin, and immunostained with monoclonal anti-keratin 3 antibodies. Incubation with phosphate buffered saline was used as the negative control, and native human corneal and oral mucosal tissues were used as the positive controls.
Surgical procedures were performed by the same surgeon (Dr. Ye). The subconjunctival fibrovascular tissue was removed, and autologous COMET was performed, as previously described [5, 10]. Then the grafted corneal surface was covered with a therapeutic soft contact lens. After surgery, tobramycin and dexamethasone eye drops were applied four times per day, and the dose was then decreased over time. During the first 3 days after surgery, dexamethasone (5 mg per day) was administered intravenously to reduce postoperative inflammation. Both best-corrected visual acuity (BCVA) and tonometry were measured; the ocular surface was also inspected by slit-lamp biomicroscopy and fluorescence staining in all patients every 2 to 4 weeks during the follow-up period, beginning one week after COMET.
Evaluation of clinical efficacy
The clinical results were evaluated and graded on a scale from 0 to 3, as follows :
The extent of conjunctiva formation was graded as follows: 0 = absence of formation, 1 = conjunctiva formation involving less than one-quarter of the corneal surface, 2 = conjunctiva formation involving one-quarter to one-half of the corneal surface, and 3 = conjunctiva formation involving more than one-half of the corneal surface.
The extent of symblepharon formation was scored as follows: 0 = no symblepharon, 1 = formation involving only the conjunctival surface, 2 = formation involving less than one-half of the corneal surface, and 3 = formation involving more than one-half of the corneal surface.
Evaluation of clinical safety
The following postoperative complications were evaluated: persistent epithelial defects lasting more than 4 weeks, infection, and ocular hypertension. Cases of preoperative ocular hypertension were not considered.