British researchers recently found contact lenses imbued with dye can block certain wavelengths of light from entering the eye, thus enhancing color perception for patients with red-green color vision deficiency.¹

The investigators, from the University of Birmingham, dyed a commercially available soft contact lens with a non-toxic rhodamine-derivative dye that can absorb wavelengths of light in the band that lies between the red and green wavelengths, which is perceived by two sets of corresponding optical cones simultaneously. The removal of this band inhibited the simultaneous triggering of the cones designated for green and red wavelength bands, enabling better differentiation between red and green colors, the investigators said.¹

The dyed lens was tested on people with red-green color vision deficiency. The results verified that dye tinted lenses can be used to enhance the color perception of people affected by color vision deficiency.¹

“The biocompatibility assessment of the dyed contact lenses in human corneal fibroblasts and human corneal epithelial cells shows no toxicity and cell viability remains at 99% after 72 hours. This study demonstrates the potential of the dyed contact lenses in wavelength filtering and color vision deficiency management,” researchers said.¹

Further patient studies are now underway.²