EFFECTS OF ULTRAVIOLET RADIATION OF EXCIMER LASERS ON SCLERAL TISSUE OF THE HUMAN EYE (EXPERIMENTAL STUDY)

Abstract

Purpose. To study an effect of excimer laser with different wavelengths (248, 308 and 353nm) on sclera.Material and methods. For the experiment 3 laser units, generating radiation with wavelengths of 248, 308 and 353nm were created. There were determined ablation thresholds, ablation speeds for the investigated lengths. The transmission spectrum for sclera in the ultraviolet range was also studied as well as histological specimens of sclera.Results. The ablation threshold range for the lengths is 250-300 mJ/cm2. A higher ablation speed of sclera was in case of 308 and 353nm wavelengths that allowed to evaporate per pulse a scleral layer significantly thicker than the laser with a 248nm wavelength. The UV-radiation more than 310nm passed through the entire scleral specimen spreading in the inner tissues. Histological research showed that collagen fibers in the area of impact are structured without any signs of coagulation damages and visible pathological changes.Conclusions. Laser radiation with a 308nm wavelength has more effective parameters for a precise impact on the sclera, and also a permissible deep penetrating ability and a damaging effect on the connective tissue structure of scleral fibers, a low absorption of physiological salt solution. The mentioned properties of this radiation allow to consider it as a prospective tool for a precise impact on the sclera.

Keywords

• excimer laser
• ablation
• sclera