According to the Glaucoma Research Foundation, approximately 2.2 million Americans have glaucoma - a leading cause of blindness in the US. Now, researchers from the University of California, Los Angeles have created nanodiamond-embedded contact lenses that they say could improve the treatment of the condition.
This is according to a study published in the journal ACS Nano.
Glaucoma is a disease caused by damage to the optic nerve in the eye - the nerve that sends electrical impulses from the retina to the brain.
The disease can cause a buildup of fluid in the eye and a breakdown of tissue that regulates fluid drainage. This damage can cause irreversible vision loss.
Patients with glaucoma are often treated with eye drops. These drops can reduce the production of fluid in the eye, or help the eye drain fluid.
The investigators note that some glaucoma patients also find it hard to keep up with their eye drop regime.
Furthermore, they say that as little of 5% of the drugs used in the eye drops can actually reach the affected area and, at times, the drug can be delivered into the eye too fast, which causes it to spill out of the eye.
With these factors in mind, the researchers looked to develop an alternative method of drug delivery with the aim of improving the treatment of glaucoma.
More effective drug-delivery
The research team combined glaucoma medication with nanodiamonds and embedded them into contact lenses. When the drugs interact with the patient's tears, the drugs are released into the eye.
The investigators explain that nanodiamonds are shaped like small soccer balls and are around 5 nanometers in diameter. They are able to fuse a variety of drug compounds and release these into the body over long periods of time.
The research team merged nanodiamonds with timolol maleate - a compound that is commonly found in eye drops used to treat glaucoma.
They explain that when timolol interacts with lysozyme - an enzyme present in tears - it is steadily released into the eye.
Explaining the benefits of this process, Kangyi Zhang, co-first author of the study, says:
"Delivering timolol through exposure to tears may prevent premature drug release when the contact lenses are in storage and may serve as a smarter route toward drug delivery from a contact lens."
The researchers say that aside from the effective drug delivery aspect of the nanodiamond contact lenses, they still allow good visual clarity for the patient.
Additionally, although stronger, they are no different in water content to standard contact lenses. This means they would be comfortable to wear and allow oxygen levels to reach the eye.
Last year, Medical News Today reported on another study that also detailed the creation of a contact lens that could deliver glaucoma drugs to the eye for 1 month.
These contact lenses were created by lacing polymer films with glaucoma drugs and embedding these into the periphery of standard contact lenses.