While there currently are glasses that help compensate for red-green color blindness, the lenses often can not be shaped to users’ prescriptions. That’s why scientists are now developing a new type of corrective contact lens — and it had been inspired by old gold-containing glass.
Like the glasses, they have a red tint that filters out certain wavelengths of light, causing the colours green and red to stand out more. As a result, red-green color blind customers are better able to differentiate between the two. Unfortunately, however, evaluations have shown that the red dye used in some of these lenses gradually leaches out into the eye, potentially causing health problems.
Led by Ahmed Salih and Haider Butt, researchers from the United Arab Emirates’ Khalifa University rather created prototype contact lenses by suspending biocompatible light-scattering gold nanoparticles within a hydrogel polymer. The scientists took their inspiration from”cranberry glass,” a centuries-old material that likewise uses gold particles to produce a red tint.
It was found that the lenses functioned best when 40-nanometer-wide particles were used, as these resisted clumping plus they didn’t filter out more wavelengths of light than was necessary — in fact, they were more selective in their own light filter than 2 commercially available brands of corrective glasses.
Importantly however, the light which they did filter out was in the 520 to 580 nanometer range, which is where the colours red and green overlap. This means that in practise, they ought to help users to better perceive green and red as two distinct colours. Clinical trials are currently being planned to see if this is indeed the case, and to evaluate the comfort of the lenses.
The study is described in a paper which was published in the journal ACS Nano.