In present paper the findings on chromosome mutations, the nature of damage and the repair of the cornea tissue after UV irradiation by excimer lasers at 193, 223 and 248 nm were made. Structural mutations induced by short-pulses UV irradiation were shown to be similar to spontaneous ones by the type, time of formation in the mitotic cycle and location of acentrics. Ten hours after irradiation of the cornea with doses of 0,09 to 1,5 J/cm2 the incidence of cells with chromosome aberrations increased linearly with dose and amounted to 11,7% at 248 nm, 5,5% at 223 nm and 2,6% at 193 nm per 1 J/cm2. No induced chromosome aberrations occurred 72 hour following irradiation. Within the dose range from 3,0 to 18 J/cm2 the cytogenesis effect of radiation was less manifest than that with the doses mentioned above, the frequency of chromosome aberrations being independent of either radiation wavelength or radiation dose and amounted of 2,5 to 3,0%. Thus, large doses of powerful short-pulse UV radiation are safe according to the structural mutation criterion.