Use of a short wavelength filter in an operating microscope.

There is growing concern over the potential phototoxic effect on the patient's retina from the coaxial illumination of the operating microscope. By replacing the existing red-free filter in the body of a Zeiss operating microscope, with a 470-nm filter, the ultraviolet and low wavelength blue light can be easily and effectively filtered from the transmitted white light. In this location, the filter can be quickly and safely rotated into or out of line with the transmitted light depending on the preference of the ophthalmologist.