The First Results of Assessing Changes in the Cornea Biomechanical Properties after Keratorefractive Surgery

Objective : to conduct a comparative analysis of the biomechanical consequences of keratorefractive surgery, depending on the laser treatment technique used on the corneal stroma in patients with moderate myopia. Materials and Methods . The study included 150 patients (150 eyes) with moderate myopia, who were divided into three groups according to the type of keratorefractive surgery (KRO) performed: group 1 — 50 patients underwent Femto-LASIK; group 2 — 50 patients underwent CLEAR surgery with a 1.5 mm incision; group 3 — 50 patients underwent CLEAR surgery with a 3.0 mm incision. All patients underwent both standard and specialized ophthalmic examinations before surgery and at various follow-up time points (1 week, 1 month, and 3 months post-surgery). Particular emphasis was placed on assessing the biomechanical properties of the cornea using the Corvis ST device. Results . The pre-operative assessment of corneal biomechanical properties revealed no statistically significant differences between the groups, with all parameters falling within the normal range. At the 3-month follow-up, the central corneal thickness (CCT) was found to be highest in group 2 (CLEAR with a 1.5 mm incision) and lowest in group 1 (Femto-LASIK) (p < 0.05). Similarly, the SP-A1 and ARTh parameters demonstrated the highest values in group 2 and the lowest in group 1 (p < 0.05). Furthermore, the IR parameter was found to be lowest in group 2 and highest in group 1 at both the 1-month and 3-month follow-up visits (p < 0.05). Conclusion . The observed dynamics of changes collectively demonstrate remodelling of the corneal biomechanical profile in the post-operative period, regardless of whether FS-LASIK or CLEAR surgery was performed. However, patients who underwent CLEAR surgery — particularly those with a 1.5 mm incision — exhibited less pronounced corneal changes. These findings underscore the critical importance of thorough pre-operative planning, which should include assessment of the initial corneal thickness, calculation of the residual stromal bed, analysis of individual biomechanical parameters, and selection of the most appropriate surgical technique to minimize corneal structural damage.