New Possibilities Of Laser Refractive Modeling Of The Cornea With Saturation Of Stroma With Riboflavin

To develop new approaches to the correction of ametropias based on refractive modeling of the cornea by an argon-fluorine excimer laser with riboflavin saturation of the stroma.

Department of Ophthalmology of FSBI "National Medical and Surgical Center named after N.I. Pirogov” of the Ministry of Health of the Russian Federation, Moscow, Russia

The study of the possibility of laser refractive modeling of the cornea based on the saturation of the stroma with riboflavin and its activation by the radiation of an argon-fluorine excimer laser was carried out on 30 porcine and 110 rabbit eyes in experiments ex vivo and in vivo.  Laser photorefractive and phototherapeutic operations (610) with saturation of the corneal stroma with riboflavin were analyzed in the clinic.   Riboflavin activation was carried out by means of secondary radiation induced by exposure to ablative and subablative energy densities of an excimer laser.  The evaluation of the reffect was carried out according to the data of complex optometric studies and the technique of two-wave optical scanning of the cornea.

The isotonic 0.25% riboflavin solution did not affect the accuracy of ablation, blocked the damaging effect of induced secondary radiation on keratocytes, nerve fibers and corneal stroma. This reduced the aseptic inflammatory response and the risk of developing an irreversible form of fibroplasia. Ablation with riboflavin initiated a damping effect of crosslinking, which increased the strength properties of the thinned cornea. The refractive keratomodeling effect of excimer laser crosslinking was found in keratoconus and secondary keratoectasias. The magnitude of this refractive effect depended on the total radiation dose. This indicated the possibility of refractive modeling without ablation of the corneal stroma.

Carrying out photorefractive and phototherapeutic operations with saturation of the corneal stroma with riboflavin and its activation by radiation of an argon-fluorine excimer laser in ablative and subablative modes opens up new possibilities for refractive keratomodeling in ametropias.