Researchers used a low-cost dye.

Researchers at the University of Birmingham in England have developed a contact lens that may help people with color blindness simply by using a low-cost dye.

In a press release, the university explains that current products on the market to help with the disorder, such as color filtering glasses, are expensive, bulky and incompatible with other vision corrective glasses.

"Contact lenses are of interest for colour blindness correction because it is easier to correct the entire field of view," said Dr. Haider Butt, lead researcher from the University of Birmingham’s Department of Mechanical Engineering and the Institute of Healthcare Technologies. "The dye processing we carried out does not need any complex preparation, it is not toxic to the human eye, and our method could be easily used in both glasses and contact lenses at low cost."

In this research, an inexpensive soft commercial contact lens was dyed with a non-toxic rhodamine derivative dye. This 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 most common form of CVD). 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 results verified that dye tinted lenses can be used to enhance the color perception of people affected by color vision deficiency, according to the release. Further patient studies are now underway.

The research was published in the journal Advanced Healthcare Materials.

"We are now looking into using a similar process to correct purple-blue colour blindness, and also to bring together a number of dyes to make lenses perform for both red-green and purple-blue colour blindness simultaneously," Butt said. "We are about to commence human clinical trials shortly."

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