Researchers have modified an off-the-shelf contact lens to correct a form of red–green colour blindness known as deuteranomaly, the most common type of colour vision deficiency.
By embedding artificially engineered thin metallic films that can be fine-tuned to interact with light – known as metasurfaces – onto the surface of commercially available rigid gas permeable contact lenses, academics from the Faculty of Engineering at Tel Aviv University in Israel restored lost colour contrast and improve colour perception by up to a factor of 10.
According to their research, published in the journal Optics Letters, the effect of the metasurface-based contact lenses on colour perception was simulated using Commission Internationale de l’Eclairage (CIE) colour spaces and conventional models of the human colour-sensitive photoreceptors.
“Problems with distinguishing red from green interrupt simple daily routines such as deciding whether a banana is ripe,” co-author Ms Sharon Karepov told a local reporter.
“Our contact lenses use metasurfaces based on nano-metric size gold ellipses to create a customised, compact, and durable way to address these deficiencies.”
The researchers found that the modified contact lens could shift incorrectly recognised colours closer to the original pigments and that lost visual contrast in red–green colour blindness could essentially be restored.
An Ishihara-based colour-blindness test – the most well-known colour perception test for red–green colour deficiencies – also confirmed contrast restoration.