Investigation of the cornea biomechanical properties after the excimer laser operations
- National Medical Academy of Postgraduate Education named by P. L . Shupic of the Ministry of Health of Ukraine
Summary. The depression of corneal stability level is an important factor of its supporting properties failure after the keratorefractive surgery. This article presents the results of study of the cornea biomechanical properties after excimer laser operations using several methods: new method of corneal rigidity evaluation in vivo using Scheimpflug camera Pentacam (Oculus) under artificial increasing of intraocular pressure; elastotonometry by Filatov — Kalfa and Ocular Response Analyzer (ORA). The studies have shown a high specificity (97.6%), sensitivity (93.3%) and accuracy (95.45%) of the new method and device for assessment of corneal rigidity in vivo. Meanwhile the use of well-known methods like elastotonometry and ORA in the same patients has allowed only admitting the presence of certain tendencies to change the biomechanical parameters, which were not statistically significant and did not allow differentiating the nature of these changes. The coefficient of cornea rigidity (KER), which changes detect the cornea biomechanical disorders, expressed variability and the level of its deformation, and correlated with the depth of the corneal ablation performed at excimer laser operations (r=0,81; p<0.05). The study also demonstrated the possibility of using the increasing KER > (+) 5,4% as the criteria of eye selection during the planning the excimer laser refractive correction, and for predicting the risk of postoperative complications. A new method or evaluating the cornea biomechanical properties in vivo can be used for quantitative diagnostics of changes of the cornea biomechanical properties after keratorefractive operations.