New research published in the journal Colloids and surfaces A: Physicochemical and technical aspects provided an alternative to laser protective eyewear through the incorporation of gold nanoparticles into contact lenses.
Study: Contact lenses loaded with gold nanoparticles for laser protection and treatment of Meibomian Gland Dysfunction (MGD). Image Credit: Audrius Merfeldas/Shutterstock.com
Why is this development necessary?
As laser-based devices are widely used in several industries such as medicine, laboratories, and entertainment, the number of accidental eye injuries has increased.
The extent of this eye damage resulting from laser exposure depends on the wavelength, power and duration of exposure. Ultraviolet (UV) radiation, composed of wavelengths from 180 to 400 nm, does not reach the retina because it is absorbed by the cornea and lens. Subsequently, this reduces damage to the retina and may instead cause damage to the cornea or lens.
In addition, other infrared wavelengths such as those relating to 1400 nm – 1 mm, are absorbed by water in the cornea, resulting in corneal burn.
Visible light, consisting of 400 to 700 nm and near infrared, including wavelengths from 760 to 1400 nm, can also be damaging and is transmitted through the cornea and lens, resulting in a potential radiation overdose on the retina – the most vulnerable part of the eye.
While the need to protect against such damage has led to the development of several laser mitigating devices, goggles and goggles, the use of this preventative equipment can be inconvenient or inaccessible for 24 hour service for various industries.
Research into soft laser-protected contact lenses incorporating nanomaterials may provide an everyday alternative.
The development of anti-laser contact lenses
Laser goggles and goggles work by using heavy metal ions or colloidal particles embedded in glass filters or by adding dyes into polymeric materials during polymerization.
Researchers have undertaken ground-breaking research in this area to develop soft laser-protective contact lenses incorporating nanomaterials.
Although there have been previous studies of graphene-coated contact lenses for EMI protection, polyhydroxyethyl methacrylate soft contact lenses loaded with Au-based silica nanocapsules for attenuation of a wide range of wavelengths, including gold nanoparticles for this new application.
The use of gold nanoparticles is optimal, as they are less than 100 nm in size, have unique optical and surface properties, and most importantly, do not cause eye toxicity, making them ideal for incorporation into lenses of contact.
The researchers used gold nanoparticles that exhibit a local maximum absorbance as a tunable wavelength of around 520 nm for 12 nm particles due to the localized surface plasmon resonance (LSPR) effect. This helps protect the eyes from accidental damage from a green laser.
The gold nanoparticles used were incorporated into a polyvinyl alcohol (PVA) contact lens due to its beneficial characteristics such as particle stabilization during manufacturing by the Turkevich method and high compatibility water content.
The desired concentration was obtained by precipitation and redispersion of the anti-solvent. The particles were then cross-linked through a freeze-thaw cycle to ultimately produce the result – PVA contact lenses loaded with gold nanoparticles (PVA GoldinLens).
The researchers also pursued another route that used commercial lenses and the incorporation of gold nanoparticles.
The incorporation of gold nanoparticles into contact lenses could revolutionize the protective equipment required in several industries to prevent accidental eye damage related to laser exposure. However, an additional application has also been explored on the use of these new lenses for the treatment of dry eyes.
Dry eye is a ubiquitous ophthalmic disease with 25% of ophthalmic patients suffering from these symptoms. This disorder can occur due to an unstable tear film, which causes higher evaporation and lower tear volumes, resulting in dryness, tearing, and eye fatigue. Meibomian gland dysfunction (MGD) is one of the leading causes of dry eye, resulting in 86% of diagnosed dry eye cases.
Patients with MGD who suffer from dry eye have small glands in the eyelid that are dysfunctional and unable to secrete oil, resulting in the loss of the lipid layer on the surface of the tears. Subsequently, this causes increased evaporation of tears.
Treatments for this disorder include anti-inflammatory or antibody eye drops, eye surgery, and hot compression therapy. Warming the glands to higher temperatures allows increased lipid secretion.
This restores the coating on the tear film and reduces evaporation rates, thereby increasing tear volume and minimizing dry eye symptoms.
With the literature supported, the researchers believe the potential of their new translation product, GoldinLens, can be used as a treatment for MGD dry eye because when heated by laser exposure, it can provide heat to the glands and start the cascading process to alleviate dry eye symptoms.
Whether providing an alternative to laser protective instruments to prevent accidental eye injury or advancing medicine through advanced optics, the use of contact lenses loaded with gold nanoparticles can be revolutionary. for the advancement of industries and medicine.
Continue reading: Plastic gold – The lightweight 18-carat nanocomposite and its applications.
Liu, Z. & Chauhan, A., (2021) Gold Nanoparticle Loaded Contact Lenses for Laser Protection and Dry Eye Treatment of Meibomian Gland Dysfunction (MGD). Colloids and surfaces A: Physicochemical and technical aspects, p.128053. Available at: https://www.sciencedirect.com/science/article/pii/S0927775721019221