Dye-tinted, soft contact lenses could be a cheap and effective treatment for colour vision deficiency (CVD), reported Birmingham university researchers. The lenses, dyed with a non-toxic rhodamine derivative dye, enhance colour perception in people with red-green CVD by blocking a band of light between the red and green wavelengths, enabling better red-green colour differentiation, they said.
Several companies are already selling glasses and custom made lenses for colour blindness correction which can be expensive for many users. The dyed lens was tested on people with red-green CVD. The dyed contact lens was applied to a glass slide and participants were asked to look at several numbers through the dyed lens, and to note whether there were any improvements to the colours or the clarity of the number. They were also asked to observe their surroundings and note whether they saw any improvements in their colour perception.
Lead researcher Dr Haider Butt said: ‘Contact lenses are of interest for colour blindness correction because it is easier to correct the entire field of view. 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.’
He continued: ‘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. We are about to commence human clinical trials.’
