A team of scientists has incorporated ultra-thin optical devices known as metasurfaces into standard contact lenses to correct deuteranomaly, a form of red-green color blindness (essentially green color deficiency). The new customizable contact lens could offer a very convenient way to help people who experience various forms of color blindness, such as this case of color perception disturbance.
A problem in the day to day
“Problems distinguishing red from green interrupt simpler daily routines, such as deciding whether a banana is ripe or not,” says Sharon Karepov, from Tel Aviv University in Israel, a member of the research team. “Our contact lenses use meta-surfaces based on nano-sized gold ellipses to create a custom, compact and durable way to address these deficiencies.”
The new lenses could help people with color blindness to regain lost color contrast and improve color perception by up to a factor of 10, according to research from Tel Aviv University (Israel) and reported in the Optics Letters magazine of The Optical Society.
The method used to correct deuteranomaly, or green deficiency, could be expanded to help other forms of color blindness , as well as other eye disorders, the researchers said.
Deuteranomaly appears mainly in men and, in it, the photoreceptor responsible for detecting green light responds to the light associated with redder colors. In people with this condition, the green-sensitive cones in the eye do not work well, making it difficult to discriminate between small differences in shades of red, orange, yellow, and green.
Scientists have known for more than 100 years that this vision problem can be improved by reducing the detection of over-perceived color, but achieving this correction in a comfortable and compact device is truly challenging.
“Glasses based on this correction concept are commercially available, yet they are significantly bulkier than contact lenses,” Karepov said. “Because the proposed optical element is ultra-thin and can be integrated into any rigid contact lens, both deuteranomaly and other vision disorders, such as refractive errors, can be treated within a single contact lens.”
When they will be available?
The metasurfaces added to the lenses improved color perception by up to a factor of 10, and nearly restored lost visual contrast. For now, contact lenses for treating color blindness will need to undergo clinical testing before they hit the market , experts say.
In this illustration, the effect that the new metasurface-based lenses would have on a person with red-green color blindness is perfectly appreciated: the image on the left is the original scene, the middle image shows how a person with deuteranomaly would see it and a photo of the right represents how that person would see the landscape with the correction lens.
Referencia: Sharon Karepov et al, Metasurface-based contact lenses for color vision deficiency, Optics Letters (2020). DOI: 10.1364/OL.384970
