Principles of Correction of Colour Deficiency by Filter Glasses

Abstract

With the aid of optimized filters we are able to shift the sensitivity curves of the L, M, S cones of the human eye along the wavelength axis. Since the shape of receptor sensitivity curve itself cannot be changed we apply a colour filter in the path of the incoming light beam to modify the spectrum. This is equivalent to multiplying the receptor sensitivity function with the filter transmission function. This method also reduces the sensitivity of the receptor but the selective colour adaptation mechanism of the eye can compensate this effect within a certain range. Using this method the maximum point of the sensitivity curve can be shifted to the desired direction. This method can be used to improve the colour vision of anomalous trichromates with shifted sensitivity curves and also to enhance the colour discrimination of the normal eye optimized for a specified task.