Imagine seeing the world in muted tones: gray sky, gray grass. Some people with color blindness see everything this way, although most cannot see specific colors. Polarized glasses can help, but they cannot be used to correct blurred vision. And the tinted contact lenses currently in development for the condition are potentially harmful and unstable. Now in ACS Nano, researchers report infusing contact lenses with gold nanoparticles to create a safer way to see colors.
Some daily activities, such as determining whether a banana is ripe, selecting matching clothing, or stopping at a red light, can be difficult for people with color blindness. Most people with this genetic disorder have trouble distinguishing shades of red and green, and red glasses can make those colors more prominent and easier to see. However, these lenses are bulky and the lens material cannot be manufactured to solve vision problems. Therefore, researchers have focused on the development of contact lenses with special tints. Although hot pink tinted lens prototypes improved red-green color perception in clinical trials, they leached the tint, raising concerns about its safety. Gold nanocomposites are non-toxic and have been used for centuries to produce “cranberry glass” due to the way they scatter light. So Ahmed Salih, Haider Butt and their colleagues wanted to see if incorporating gold nanoparticles into contact lens material instead of tint could safely and effectively enhance red-green contrast.
To make the contact lenses, the researchers uniformly mixed gold nanoparticles into a hydrogel polymer, producing rose-tinted gels that filtered light within 520-580 nm, the wavelengths where red and green overlap. The most effective contact lenses were those with 40 nm wide gold nanoparticles, because in testing, these particles did not clump together or leak out more color than necessary. In addition, these lenses had water retention properties similar to commercial ones and were not toxic to cells growing in Petri dishes in the laboratory. Finally, the researchers directly compared their new material with two pairs of commercially available polarized glasses and with their previously developed hot pink tinted contact lenses. The gold nanocomposite lenses were more selective in the wavelengths they blocked than the glasses. The new lenses matched the wavelength range of tinted contact lenses, suggesting that gold nanocomposites would be suitable for people with red-green color problems without the potential safety concerns. The researchers say the next step is to conduct clinical trials with human patients to assess comfort.
New development in contact lenses for red-green color blindness using a simple tint
Ahmed E. Salih et al. Gold nanocomposite contact lenses for color blindness control, ACS Nano (2021). DOI: 10.1021 / acsnano.0c09657
Provided by the American Chemical Society
Citation: Contact lenses to correct color blindness (2021, March 3) retrieved March 3, 2021 from https://phys.org/news/2021-03-blindness-correcting-contact-lenses.html
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