Рибофлавин в профилактике фиброплазии в лазерной рефракционной хирургии роговицы

Abstract

Purpose: To substantiate the use of riboflavin for the prevention of subepithelial and intrastromal fibroplasia in laser refractive corneal surgery. Material and methods: The work is based on 9-year clinical observations of the results of photorefractive and phototherapeutic corneal surgery with stroma saturation with riboflavin (more than 700 operations). Keratoablation was performed after drip, aerosol or combined saturation of the stroma with 0.1 % or 0.25 % chilled isotonic riboflavin solution. Corneal OCT was performed on RTVue 100 and RTVue XR100 devices. Keratotopographic and densitometric studies were performed on a TMS-5 instrument. These devices were used with two-wavelength optical scanning in the visible green and infrared ranges to assess prophylactic crosslinking by the change in the refractive index of the cornea. Results: During photokeratoablation, corneal stroma layers saturated with riboflavin acted as spectral filters, protecting keratocytes from secondary radiation induced by ablation. This reduced the response of aseptic inflammatory and regenerative reactions, the severity and duration of the corneal syndrome. According to OCT and corneal densitometry data, the formation of a Bowman-like structure on the ablation surface was noted with an increase in optical density in the underlying layers of the stroma. Two-wavelength optical scanning revealed a significant increase in the refractive index. The effect of laser-induced crosslinking and the increase in optical density had a damped character and did not exceed 1/2 of the stroma thickness. These changes in the cornea were a barrier between pro-inflammatory epithelial and stromal cytokines that stimulate the development of subepithelial and intrastromal fibroplasia after photokeratoablation. Conclusion. During photokeratoablation, riboflavin-saturated layers of the corneal stroma protect deeper-lying keratocytes from secondary radiation induced by ablation, and the formation of a Bowman-like structure on the ablation surface with a damping effect of crosslinking in the superficial layers of the stroma prevents the development of fibroplasia. Keywords: Riboflavin, Mitomycin-C, fibroplasia, photoablation, excimer laser corneal surgery, laser-induced crosslinking.