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Contact Lens Material Reduces Color Blindness

Red-blue-green eye

(Public Domain Pictures, Pixabay)

5 Mar. 2020. An engineered ultra-thin material designed for contact lenses is shown in lab tests to help correct for a common form of color blindness. Findings from research engineers at Tel Aviv University in Israel appear in today’s issue of the journal Optics Letters, published by The Optical Society (paid subscription required).

A team from Tel Aviv’s Nanoscale Electro Optics Laboratory is seeking better solutions for people with deuteranomaly, a form of red-green color blindness and the most common form of color blindness. Deuteranomaly results in reduced sensitivity to green light, and is found more often in men than women. The condition arises from photoreceptor cells in the retina known as cones erroneously react to green colors as red.

Basic concepts for resolving red-green ambiguities are well known, say the researchers, but up to now, corrective lenses for glasses have not been practical solutions. “Glasses based on this correction concept are commercially available,” says doctoral student and first author Sharon Karepov in an Optical Society statement, “however, they are significantly bulkier than contact lenses.”

Karepov and electrical engineering professor Tal Ellenbogen applied their lab’s research on nanoscale synthetic materials to find a solution. Karepov and Ellenbogen applied earlier work on nanoscale gold ellipses to design a synthetic surface material that adjusts light waves transmitted through it. The nanoscale elements in the ultra-thin synthetic material make it possible to produce specific desired effects in light transmission, in this case correcting for colors in the light sent through the surface.

However, the researchers had to solve another problem. In previous work, synthetic materials of this kind were designed for flat surfaces, and contact lenses are curved. As a result, the team modified its fabrication process to apply the synthetic material to curved, as well as flat surfaces. Tests of the material with the synthetic material show the color-adjustment properties of the nanoscale components in the surface were not affected when applied to curved surfaces.

The researchers lab tested simulated contact lenses made with the synthetic material, using color spaces defined by the International Commission on Illumination, a worldwide standards body on light, color, and vision. These standards enabled the team to quantify the degree of improvement from the synthetic material, which show a ten-fold increase in color correction from before to after. Further tests with the standard Ishihara color-blindness test show the synthetic material restores nearly all of the color contrast lost in people with deuteranomaly.

The researchers designed the study to prove the concept, but they believe their synthetic material can be incorporated into today’s production contact lens production process. The team also feels the material can be applied to other vision problems addressed by contact lenses. “Because the proposed optical element is ultrathin and can be embedded into any rigid contact lens,” notes Karepov, “both deuteranomaly and other vision disorders such as refractive errors can be treated within a single contact lens.”

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