The apparatus including an optical arrangement including at least one light guide wherein the at least one light guide is configured to propagate a beam of light from an image source towards a user's eye to direct the beam of light to a location proximate to the user's eye. The apparatus also including absorptive material positioned within the optical arrangement so as to absorb light having a first wavelength from the optical arrangement and re-emit light having a second wavelength where the second wavelength is different to the first wavelength.