FLUENCE AND MUTAGENIC SIDE-EFFECTS OF EXCIMER-LASER RADIATION APPLIEDIN OPHTHALMOLOGY IN HUMAN-LYMPHOCYTES IN-VITRO

Purpose: To investigate the influence of different fluences in 193 and 248 nm excimer laser radiation on the yields of chromatid and chromos ome aberrations induced in human lymphocytes in vitro, Method: Heparin ized human blood was exposed to 193 or 248 nm excimer laser radiation, The fluence was gradually increased from 21 to 400 mJ/cm(2) in 193 nm (constant total energy of 250 J) and from 150 to 377 mJ/cm(2) in 248 nm radiation (constant total energy of 500 J), Chromatid and chromosom e aberrations were then analysed microscopically, Results: The yields of chromatid breaks and achromatic lesions depend on the fluence per p ulse, This dependence contains a linear component, indicating a thresh old of about 70 mJ/cm(2) fluence in 193 nm and of about 250 mJ/cm(2) f luence in 248 nm laser radiation. An increase of the yield of dicentri c chromosomes could only be observed at the highest fluence tested (37 7 mJ/cm(2)) in the 248 nm series. Over 126 mJ/cm(2) in 193 nm radiatio n no lymphocytes could be cultured and therefore no aberrations could be found, Conclusions: Our findings show that the fluence of 193 nm an d of 248 nm excimer laser radiation has an effect on the yields of chr omatid breaks and achromatic lesions in human lymphocytes under in vit ro conditions.