A new study says that body fluids could make great contact lens moisturizers in what may be welcome news for contact lens users struggling to combat dryness.
Findings from researchers at Hamilton's McMaster University show that a common fluid found in the body can be used as a natural moisturizing agent in the lenses.
This is a step up from the current wave of self-moisturizing contact lenses that use synthetic materials as a wetting agent to prevent eye dryness and increase wearer comfort.
The study showed that hyaluronic acid could be entrapped in existing contact lens material without affecting optical properties.
Researchers also found that using hyaluronic acid considerably reduces the build up of proteins, which can cloudy contact lens material, the cause of up to 30 per cent of all after-care visits by contact lens wearers to optometrists.
Hyaluronic acid is a natural polymer that acts to reduce friction. An average person weighing 70-kg has about 15 grams of hyaluronic acid in their body, one third of which is turned over daily.
The body uses hyaluronic acid to repair skin, provide resiliency in cartilage, and contribute to the growth and movement of cells, among other things.
It is also used by the medical profession to treat patients with dry eyes, in cataract surgery, and for other eye-related procedures.
Manufacturers have not yet produced contact lenses with hyaluronic acid, but researchers remain hopeful.
"We've shown that the process works," said co-author Heather Sheardown, professor of chemical engineering at McMaster and a member of the McMaster School of Biomedical Engineering.
"We're optimistic that a manufacturer will see the benefits of using this naturally based technology to provide contact lens wearers with greater comfort and convenience," Sheardown added.
The study was published in the journal Biomaterials.