Cases of lack of therapeutic effect of corneal collagen crosslinking in treatment of keratoconus

Purpose. Study of changes in morphometric parameters of cornea in keratoconus before and after corneal collagen crosslinking (CXL). Material and methods. 35 patients (35 eyes) with progressive keratoconus stages 1–3. The indexes of photokeratoscopy were studied in depth (topographer Pentacam (Oculus, Germany). CXL was performed according to the Dresden protocol. A corneal lenticule was used in 6 eyes. The analysis of the studied parameters was carried out initially and after 12 months. Results. By the end of the observation, in all patients, the average values of maximum keratometry (Kmax) decreased statistically significantly from 54.5 to 53.1 diopters, which indicated positive trend. Most indices of keratoconus according to topographer data (ISV, IVA, KI, CKI, IHA, Rmin), as well as the central corneal thickness, on average, significantly decreased. But in 5 patients (all men, mean age 25 years), the Kmax exceeded initial values (from 61.7 to 64.5 diopters), which indicated further progression of keratoconus. The initial values of Kmax in 3 out of 5 of these patients exceeded 57 diopters, which is risk of further progression of keratoconus. Conclusion. With a follow-up period of one year, it was found that CXL in 5 patients (14 %) with keratoconus stages 2-3 turned out to be ineffective. Keywords: keratoconus, photokeratoscopy, corneal collagen crosslinking