Fig. 2

Modifications to the operating room. a In the operating room, several emitters are covered with the special film. The light intensity of the ceiling light did not change the 400 nm region of the light wavelength measured on the surgical table, so for the convenience of the surgery, the ceiling light was not filtered. b The laryngoscope’s light is also covered with the film. c We measured the lights at the operation table. We confirmed that the film completely blocked light with a wavelength of 400 nm. (Left) without the film, (right) with film attached (yellow circle). d We could safely manage the operation in a sufficiently bright environment