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Abstract
The amount of unscheduled DNA synthesis (UDS) produced in the cells adjacent to excimer laser ablations in the cornea was compared for 193-nm and 248-nm laser wavelengths. UDS is interpreted to indicate the process of excision repair of pyrimidine dimers formed in DNA. 193-nm laser ablation did not produce a statistically significant difference in the amount of UDS as compared to a negative control (diamond-knife corneal incision). However, 248-nm laser ablation did produce a highly statistically significant difference in the amount of UDS as compared to both the negative control (P < 0.001) and the 193-nm laser irradiation (P < 0.001). Other forms of DNA damage (single-strand DNA chain breaks and DNA-protein crosslinks) are not measurable by UDS and need to be investigated in the evaluation of the oncogenic potential of 193-nm laser ablation.