Engineers have developed a new method to deliver time-release doses of eye medication through contact lenses.
The lenses deliver a constant flow of drugs – such as anti-inflammatories, antibiotics and anti-allergy treatments – without altering the wearer’s vision, OR they can be used to correct vision while also delivering eye medication.
Soft contact lenses are made out of a water-absorbing substance called hydrogel. By changing the way the molecule chains are built, Mark Byrne from Auburn University and his team found a way to load drugs onto the lenses, and tailor the timed release of these drugs to a prescribed therapy.
They’re called molecularly imprinted therapeutic contact lenses.
"These aren't contacts soaked in a medication that only release for a very short time,” Byrne says. “We are administering a drug through controlled release by creating drug memory in the lens structure while maintaining all of the other lens properties."
They tested their lenses on New Zealand white rabbits and maintained a steady, effective concentration of a drug in tear fluid for the duration of lens wear (or about 24 hours in this case).
The lenses were 94 times more effective than eye drops.
Eye drops and ointments make up more than 90% market share, Byrne says, but are an inefficient, inconvenient method. (They usually end up streaming down cheeks, and even if they get into the eye, they usually wash away within half an hour.)