The present study compares, using a new generation high-resolution in vivo confocal microscope, the corneas of patients who underwent photorefractive keratectomy (PRK) 10 years previously with those of healthy persons.

A confocal microscope (Confoscan 4.0, Fortune Technology, Italy) was used to get the data from healthy volunteers and patients. Corneal cross-sectional images of the epithelium, Bowman's layer, stromal layer (anterior, middle and posterior keratocyte), Descemet's membrane, and endothelium were compared. In PRK corneas, the superficial epithelium was nearly intact and the subbasal nerve plexus was visible, but some hyperreflective areas were also found in the nerve plexus. Because of the absence of the Bowman's layer, some ECM and keratocytes were visualized in their optical section. Although anterior keratocytes showed uneven distribution with less cellularity, middle and posterior keratocytes looked unaffected. Likewise, there were no differences in the endothelium between the two groups.

Ten years after PRK, the subbasal nerve plexus and anterior keratocytes showed histologic changes after corneal wound recovery.