Glaucoma can be treated with daily eye drops, but their fiddly nature can affect patient adherence. A team from Massachusetts has developed a drug-delivering contact lens that is at least as effective as daily eye drops in animal models.
There is no cure for glaucoma, which refers to a group of diseases that damage the optic nerve and could lead to vision loss and blindness. Medications that lower intraocular pressure come in the form of eye drops, but they are difficult to self-administer and can cause stinging or burning. Some studies find patient compliance to eye drops to be as low as 50%, according to a statement.
While researchers have explored drug-delivering contact lenses for decades, the main challenge is that they tend to release the drug too quickly. The team, comprising scientists from Massachusetts Eye and Ear, Boston Children’s and Harvard Medical School, worked on a more controlled way to dispense the drug.
"Instead of taking a contact lens and allowing it to absorb a drug and release it quickly, our lens uses a polymer film to house the drug, and the film has a large ratio of surface area to volume, allowing the drug to release more slowly," said senior author Dr. Daniel Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Boston Children's Hospital, in the statement.
The drug-polymer film is on the periphery of the lens, so the center of the lens is clear, enabling normal vision, breathability and hydration, the researchers said. The lens can be purely drug-delivering, or can be made with refractive power to correct near- or farsightedness.
In a study published this week in Ophthalmology, the team demonstrated that their lens, which delivered lower doses of latanoprost, resulted in the same reduction in eye pressure as did latanoprost eye drops. And lenses with a higher dose performed better than the drops. The team tested the lenses in four glaucomatous monkeys. Further studies are required to confirm the efficacy of higher-dose lenses. The team is also designing clinical trials to assess the lenses’ safety and efficacy in humans.