Special Glass Filters Can Improve Color Visualization in Color Blind People

In a new study conducted at the UC Davis Eye Center, in collaboration with France’s INSERM Stem Cell and Brain Research Institute, it was discovered that a special form of patented glasses engineered with technically advanced “spectral notch filters” can significantly improve the color vision, particularly for those individuals who are color blind with the types of red-green color vision deficiency (‘anomalous trichromacy’). The study has been published in Current Biology.

In the study, it was found that at least 8% (8/100 men) and 0.5% (1/200 women) commonly suffer from the “red-green color vision deficiency (CVD)”. In total, over 10 million in United States and over 350 million globally are affected. Relative to individuals with normal color vision, who see more than one million hues and shades, individuals with CVD see a vast diminished range of colors. People who suffer from CVD experience colors which are perceived as more muted and washed out, and some colors cause confusion or are more difficult to differentiate.

Source: Wendi Butler

In this study, from up to 40,000 individuals including undergraduates and graduates at UC Davis, an estimated 1,700 students were with red-green CVD. The study critically analysed the impact of spectral notch filters on improving the chromatic responses of observers with red-green CVD, for over two weeks of usage. The filters, “EnChroma glasses”, are designed in a way to increase the separation between color channels to help people with color blindness see colors more vibrantly, clearly and distinctly.

The research included CVD participants, divided onto groups, who were asked to wear the special filter glasses and placebo glasses. For over two weeks, the participants keep logging their response in a diary. Then they were tested again on days 2, 4, and 11, but without wearing the glasses. The researchers found that by wearing the filter glasses, the response to chromatic contrast has increased in people with red-green color blindness. It was not clear for how long the improvement lasts without wearing the filters, but the evidence shows that the effect remains persistent for some time.

John S. Werner, a professor of ophthalmology and a leader in vision science at UC Davis Health, said, that the “Extended usage of these glasses boosts chromatic response in those with anomalous trichromacy (red-green color vision deficiency). 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.”

He said that he observed, use of broad-band filters sold as aids to the color blind, cannot cause this effect. He and his research colleagues believe the study’s findings suggest that modifications of photoreceptor signals activate a plastic post-receptoral substrate in the brain that could potentially be exploited for visual rehabilitation.

Further, to confirm the positive response from the participants about their experiences with the glasses, Supplement section of the Current Biology article can be found.

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