Incision depth vs. incision number in the rupture strength of pig eyes following radial keratotomy

The effects of incision depth and the number of incisions on globe rupture were studied in porcine enucleated eye model. In one group, radial keratotomy was performed using a diamond blade set at 100%, 75%, and 50% of corneal thickness. In another set of eyes, 16, 8, and 4 incisions were made with the diamond knife set at 100% of corneal thickness. The eyes were then subjected to blunt trauma. The mean energy of globe rupture for incisions at 100%, 75%, and 50% of corneal thickness was 3.0, 4.2, and 4.6 joules respectively. In contrast, mean energy of globe rupture for 16, 8, and 4 incisions at 100% corneal thickness was 2.8, 2.9, and 3.0 joules, respectively. This study suggests that incision depth in radial keratotomy reduces the strength of the cornea more than incision number.