OPHTHALMIC FILTER MATERIALS

摘要

An ophthalmic filter material having a photopic transmittance (Yp) higher than the scotopic transmittance (Ys), the ratio of Yp:Ys being in the range of 2.0-4.0, a dominant wavelength within the ranges of 580-605 nm and a color purity of 60-75 % whereby colors perceived through the material approximate those of the scene being viewed. A method of producing such a filter material which comprises heating a photochromic glass lens in a reducing atmosphere for a time and at a temperature that is sufficient to impart the recited characteristics to the glass surface and that is equivalent to a flowing hydrogen atmosphere, or immersing a tintable plastic solution in a dye solution for a time sufficient to impart the recited characteristics.