Three-dimensional organization of collagen fibrils during corneal stromal wound healing after excimer laser keratectomy

Purpose: To investigate the structural changes in corneal stromal collagen fibrils after excimer laser keratectomy in relation to the degree of corneal haze. Setting: University of Tokyo Hospital, Tokyo. Japan Methods: Corneal haze was quantitatively measured by analyzing the light scattering in Scheimpflug Images of the corneas of white rabbits after excimer laser keratectomy. Collagen fibril structure was examined using scanning electron microscopy after chemical digestion with sodium hydroxide solution; the same specimens were examined by transmission electron microscopy after re-embedding. Results: Corneal haze reached a peak 4 weeks after excimer laser keratectomy and the gradually decreased. The collagen fibrils of the normal cornea were regularly arranged parallel to the surface of the cornea, with small interfibrillar distances. After excimer laser keratectomy, the arrangement was highly disordered, with increased interfibrillar distances. These structural changes were most prominent weeks after excimer laser keratectomy. Conclusion: The structural changes in the collagen fibrils of the corneal stroma, especially the increase in interfibrillar distances and the disordered arrangement, were associated with corneal haze after excimer laser keratectomy.