Dynamics of keratotopographic and biomechanical parameters of the cornea after accelerated ultraviolet crosslinking using a donor cornea protective flap in the treatment of progressive keratoconus with "thin cornea"
Authors:   Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Kaluga, Russia, Tereshchenko A.V. , Trifanenkova I.G. ,   Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Kaluga, Russia, Demyanchenko S.K. ,   Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Kaluga, Russia, Vishnyakova E.N. ,   Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Kaluga, Russia, Golubeva Y.Y. ,   Kaluga branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Kaluga, Russia
Published: October 2022

Purpose. To analyze changes in the biomechanical and topographic parameters of the patient's cornea using the Corvis st (OCULUS, Germany) and Pentacam (OCULUS, Germany) device before and after accelerated ultraviolet crosslinking of the cornea using a donor cornea protective flap in the treatment of progressive keratoconus with "thin cornea" and compare the obtained data with the results after classical accelerated crosslinking. Material and methods. According to the proposed technology, 26 patients (26 eyes) were operated on with a diagnosis of progressive keratoconus 2nd stage with corneal pachymetry less than 400 µm, mean value 390 ± 40 µm. Comparison group – patients diagnosed with progressive keratoconus 2nd stage with corneal pachymetry over 400 µm, mean value 450 ± 40 µm, comparable in age and gender, being operated on using the technology of classical accelerated crosslinking. In addition to standard research methods, before and after surgery, patients underwent an assessment of the biomechanical and topographic parameters of the patient's cornea using the Corvis st (OCULUS, Germany) and Pentacam (OCULUS, Germany) devices. Results. The results obtained in both groups were comparable in all parameters: there was a decrease in keratometric parameters in the first months after the operation, with their further stabilization during the entire period of observation. The pachymetry value remained stable, no significant changes in UCVA and Correctable Visual Acuity were detected. Evaluation of specific keratotopographic indices (ISV, IVA, KI, CKI, IHD) showed their decrease both in the main and control groups, and Rmin tended to increase. The value of the inscribed radius tended to decrease, which indicates an increase in the stiffness of the cornea after classical accelerated crosslinking and crosslinking of the proposed technology. Conclusion. Application of the technology of accelerated ultraviolet crosslinking using a protective flap of the donor cornea in the treatment of progressive keratoconus with "thin cornea" leads to an increase in the rigidity of the cornea and stabilization of the ectatic process of the cornea in the postoperative period, just as with the classical technology of accelerated crosslinking. Keywords: progressive keratoconus, "thin cornea", accelerated ultraviolet crosslinking using a donor cornea protective flap, keratopotographic parameters of the cornea, biomechanical parameters of the cornea.