Abstract
Abstract: :
Purpose: To compare corneal re-epithelialization over amniotic membrane (AM) sutured on corneal defects in two orientations: AM basement membrane anterior (BMA) and AM basement membrane posterior (BMP). Methods: Four pairs of cadaver eyes were acquired from the eye bank. The excimer laser was used to ablate the anterior 150 microns of the central 6.5 mm of the cornea. A 6.0 mm disc of fresh frozen AM was sutured over the ablated area with interrupted 10-0 Nylon sutures. Each pair of globes had the AM placed BMA in one eye and BMP in the other. The corneoscleral button was excised from the globe and placed in culture media. Corneal re-epithelialization was evaluated by fluorescein staining. Digital photographs of the epithelial defects were obtained, and the area of epithelial defects was calculated using image analysis software. After complete re-epithelialization, the corneoscleral buttons were sectioned and stained for histopathologic examination. Results: Eight corneas were examined, four with BMA and four with BMP. Histopathology was performed on all 8 corneas. In all of the corneas, there was a robust 1-3 cell layer of epithelium on the basement membrane side of the AM, regardless of anterior or posterior orientation. On the stromal side of the AM, regardless of orientation, there was an incomplete, fragmented monolayer of epithelium. No significant difference was noted in the rate of epithelialization between BMA and BMP. Conclusions: Corneal re-epithelialization rates are not influenced by the orientation of the AM. Corneal epithelium has a greater affinity toward the basement membrane of the AM, regardless of orientation. Clinicians should consider this finding and realize that while epithelium may grow on both sides of the amniotic membrane, the majority of re-epithelialization takes place on the basement membrane surface.
Keywords: cornea: epithelium • cornea: clinical science • wound healing