Ocular biomechanical measurements on post- keratoplasty corneas using a Scheimpflug-based noncontact device

AIM： To analyse ocular biomechanical properties, central corneal thickness （CCT） and intraocular pressure （lOP） in post-keratoplasty eyes, as compared to normal subjects, with a new Scheimpflug-based technology. Moreover, biomechanical data were correlated with the size and age of the donor and recipient corneas. METHODS： Measurements were conducted on 46 eyes of 46 healthy patients without any corneal pathology （age： 53.83 ±20.8y） and 30 eyes of 28 patients after penetrating keratoplasty （age： 49.43 ±21.34y）. Ten biomechanical parameters, the CCT and lOP were recorded by corneal visualization Scheimpflug technology （CorVis ST） using high-speed Scheimpflug imaging. Keratometry values were also recorded using Pentacam HR system. Scheimpflug measurements were performed after 43.41± 40.17mo （range： 11-128mo） after the keratoplasty and after 7.64±2.34mo （range： 5-14mo） of suture removal. RESULTS： Regarding the device-specific biomechanical parameters, the highest concavity time and radius values showed a significant decrease between these two groups （P=0.01 and P 〈0.001）. None of other biomechanical parameters disclosed a significant difference. The CCT showed a significant difference between post keratoplasty eyes as compared to normal subjects （P= 0.003） using the CorVis ST device. The lOP was within the normal range in both groups （P=0.84）. There were no significant relationships between the keratometric data, the size of the donor and recipient, age of the donor and recipient and biomechanical properties obtained by CorVis ST. CONCLUSION： The ocular biomechanics remain stable after penetrating keratoplasty according to the CorVis ST measurements. Only two from the ten device-specific parameters have importance in the follow-up period after penetrating keratoplasty.