A new UC Davis Eye Center study, in collaboration with France’s INSERM Stem Cell and Brain Research Institute, found that EnChroma patented glasses engineered with technically advanced spectral notch filters enhance colour vision for those with the most common types of red-green colour vision deficiency (“anomalous trichromacy”). Notably, the ability to identify and experience expanded colour was also demonstrated when colour blind test subjects were not wearing the glasses. At least eight in 100 men (8%) and one in 200 women (0.5%) suffer from red-green color vision deficiency (CVD), totaling 13 million in the U.S. and 350 million worldwide. While those with normal colour vision see in excess of one million hues and shades, the CVD see a vastly diminished range of colours. People with CVD experience colours as more muted and washed out, and some hues cause confusion or are more difficult to differentiate. With an undergraduate and graduate student body of nearly 40,000, UC Davis has an estimated 1,700 students with red-green CVD. The study evaluated the impact of spectral notch filters on enhancing the chromatic responses of observers with red-green CVD over two weeks of usage. The filters (EnChroma glasses) are designed to increase the separation between colour channels to help people with colour blindness see colorus more vibrantly, clearly and distinctly. The research, published in Current Biology, had CVD participants wear the special filter glasses or placebo glasses. Over two weeks, they kept a diary and were re-tested on days 2, 4 and 11 but without wearing the glasses. The researchers found that wearing the filter glasses increased responses to chromatic contrast response in individuals with red-green colour blindness. It is unclear how long the improvement lasts without wearing the filters, but the evidence shows that the effect persists for some time. “Extended usage of these glasses boosts chromatic response in those with anomalous trichromacy (red-green colour vision deficiency)”, said John S. Werner, distinguished professor of ophthalmology and a leader in vision science at UC Davis Health. “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”.