Alex Zbylut, a colour-blind study participant in EnChroma glasses

A joint US-French study has found that the effects of Enchroma glasses, designed to enhance the colour vision of those who have red-green colour vision deficiency (CVD), persist even after they have removed the glasses. 

UC Davis Eye Center and INSERM Stem Cell and Brain Research Institute evaluated the impact of spectral notch filters on enhancing the chromatic responses of observers with red-green CVD over two weeks wear, compared with placebo glasses.  

The researchers found that wearing the filter glasses increased responses to chromatic contrast response in individuals with red-green colour blindness, and that the effect lasted for some time.  

“When I wear the glasses outside, all the colours are extremely vibrant and saturated, and I can look at trees and clearly tell that each tree has a slightly different shade of green compared to the rest," said Alex Zbylut, a colour-blind study participant who received the placebo glasses first and then tried the EnChroma glasses.  

“Extended usage of these glasses boosts chromatic response in those with anomalous trichromacy,” said lead author, Professor John Werner. “We found that sustained use over two weeks not only led to increased chromatic contrast response but, importantly, these improvements persisted when tested without the filters, thereby demonstrating an adaptive visual response.” 

The findings suggest that modifications of photoreceptor signals activate a plastic post-receptoral substrate in the brain that could potentially be exploited for visual rehabilitation, he added. 

The full study is published in Current Biology.