Background: Photosensitized patients are exposed to bright lights when undergoing intraoperative photodynamic therapy or fluorescence measurements. Acrylate yellow filters might reduce unwanted tissue damage.
Methods: To investigate the protective value of these filters, the spectral power distribution of the operating lights and light energy densities with and without an acrylate yellow filter were measured. Subsequently the effects of light exposure on the survival of a human hepatocellular carcinoma cell line and the photodamage induced in pig tissues after the administration of 5-aminolaevulinic acid were also studied.
Results: The light energy density in the ultraviolet and blue region of the light spectrum emitted by the operating light was reduced up to 50 per cent by the acrylate yellow filter. The survival of photosensitized cells was longer and photodamage induced in pig tissues was less when exposed to filtered light.
Conclusion: Photodamage induced by operating lights can be reduced by filtering out ultraviolet and blue light by means of acrylate yellow filters.