Researchers at the University of Birmingham have developed a contact lens that may help people with color blindness simply by using a low-cost dye, according to research published in the journal Advanced Healthcare Materials.
Color blindness is an inherited disorder where some people have difficulty distinguishing certain colors. While no cure exists, several methods have been used to increase the color perception of those affected. However, current products on the market such as color filtering glasses are often pricey.
Human color vision is trichromatic, combining the colors blue, red and green, which are perceived by a cluster of cones at the back of the eye. These cones are divided into three groups, responsible for short wavelengths – blue – medium wavelengths – green – and long wavelengths – red. In normal vision all three are present. When any of these cones are missing, the brain receives incorrect information leading to a greatly reduced ability to identify certain colors.
Several companies are already selling glasses and custom made lenses for color blindness correction which can be expensive for many users, however, in this research, an inexpensive soft commercial contact lens was dyed with a non-toxic rhodamine derivative dye. This particular derivative of rhodamine was chosen as it is known for its ability to absorb certain wavelengths of light in the optical spectrum. Researchers found that the dye blocked 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 through the dyed lens inhibited the simultaneous triggering of the cones designated for green and red wavelength bands, enabling better differentiation between red and green colors.
The dyed lens was tested on people with red-green Color Vision Deficiency The dyed contact lens was applied to a glass slide. The participants were asked to look at several numbers through the dyed lens and to note whether there were any improvements to the colors or the clarity of the number. They were also asked to observe their surroundings and note whether they saw any improvements in their color perception. The dye processing does not need any complex preparation, is not toxic to the human eye, and could be easily used in both glasses and contact lenses at low cost. Further testing and human clinical trials are set to begin soon.
SOURCE: University of Birmingham