Histopathologic comparison of conventional radial keratotomy and minimally invasive radial keratotomy in rabbits

The aim of the present study was to compare conventional radial keratotomy (RK) with minimally invasive RK (mini-RK) in terms of achieved incisional depth as well as the histopathologic changes in the rabbit corneal structures. Four conventional RK incisions were performed on the right eye and four mini-RK incisions were performed on the left eye of 12 Island rabbits using a centripetal cutting technique. The corneas were excised 20 days after the procedure and examined by light microscopy. Histopathologic examination showed that the mean achieved incisional depth (73.47%) in conventional RK was consistent with the intended incisional depth (80%), However, the mean achieved incisional depth (47.28%) was far from the intended incisional depth (80%) in eyes receiving mini-RK. The difference be tween achieved incisional depth of the two surgical techniques was statistically significant (t = 10.70, P < 0.05). Corneal structural changes and epithelial plug formations were less in eyes in mini-RK than in conventional RK. These findings suggested that the refractive results in mini-RK may be less effective than conventional RK. On the other hand, in the mini-RK group, less epithelial plug formation and limited histopathologic structural alterations may have an important role in preventing long-term overcorrection and corneal rupture after ocular trauma demonstrated in conventional RK technique. (C) 1997 Japanese Ophthalmological Society.