RADIAL KERATOTOMY INCREASES OUTFLOW FACILITY IN THE PORCINE EYE IN-VITRO

Purpose. To investigate the biomechanical effect induced by radial ker atotomy on outflow facility in paired, enucleated whole porcine eyes. Methods. Freshly enucleated porcine eyes were perfused at a constant p ressure of 10 mm Hg. Radial keratotomy (RK), with a 3.5 mm central cle ar zone and eight radial incisions, was performed using a diamond knif e with the blade length set at 100% of the paracentral corneal thickne ss, as measured by pachymetry The fellow eye of each pair received sha m RK as a control. Results. Seven pairs of eyes were perfused (RK grou p n = 7, control n = 7). There was no significant difference in the me an baseline of outflow facility between the paired experimental and co ntrol eyes preoperatively (p = 0.5). After RK, outflow facility increa sed by 46% (p < 0.001) in the treatment group, compared to a 7% (p < 0 .04) increase in the control group, resulting in a 39% increase in out flow facility attributed to RK (p < 0.001). Conclusions. Radial kerato tomy produced a statistically significant acute increase in outflow fa cility in freshly enucleated porcine eyes. We believe that this increa se results from steepening of the peripheral corneal curvature and the concomitant stretching of the iridocorneal angle. Further studies are needed to evaluate this effect in human eyes and in vivo.