Figure 4. Slit lamp examination of nude rat eyes showing the total epithelial defect of the corneal surface on Day 1 after corneal injury. A representative photo of corneal defect pre-implantation showed positive fluorescein staining (green). The absence of the green color in the rest of the photos shows that full coverage of the corneal epithelium has been achieved by Week 2. Microscopic evaluation is also shown at 2 weeks, 4 weeks, and 8 weeks after implantation.