A rather novel drug-infused contact lens has finished animal testing and shows potential to be an effective glaucoma treatment that could be used as an alternative to eye drops. The lenses are intended to reduce eye pressure and hopefully avoid the blindness that glaucoma inevitably causes.
In Brief: Glaucoma
Glaucoma occurs when unusually high pressure builds up within the eye and starts to damage the optic nerve. The condition acts silently and gradually, so many people don’t notice their vision is being impaired until it reaches an advanced state. Glaucoma has no cure, so any lost vision can’t be reversed, and is one of the leading causes of blindness in the United States. The primary treatment for glaucoma is the use of medicated eye drops to reduce the eye pressure. However, eye drops are difficult to self-administer, can be imprecise, and have a notoriously low compliance rating. Since hard-to-use medications that patient’s have trouble sticking to is never a good thing, there has been an ongoing search for alternatives.
And Now, Contact Lenses
People have been trying to use contact lenses as a drug delivery vehicle for almost 50 years. The problem most have encountered is that the lenses tend to release the drug too quickly. What the researchers have done is createa thin polymer film on the lens that contains the glaucoma drug, latanoprost. The film slows the rate at which the drug is released, allowing for the steady dosing needed for proper effectiveness.
It was found that, at lower doses, the contact lenses worked about as well as latanoprost eye drops. At higher doses, the researchers were surprised to find that the lenses did an even better job at reducing eye pressure, though this particular finding will need further exploration.
Since this was a pre-clinical study done using monkeys, it is important to remember that the contact lens drug delivery model is still in its early stages. Clinical trials are being planned to see whether the lenses can be effective or safe in humans, though right now the odds seem to be in the researchers’ favor. As mentioned, eye drops are a finicky method of glaucoma treatment, and patients, on average, don’t take the drops as often as they need to for reducing eye pressure.
Even if the lenses turn out not to be as effective as eye drops in people, they might still be a success if they show higher compliance rates. After all, less effective but easier to use may be a better option for some patients if the alternative is not taking eye drops and going blind. Hopeful speculation, to be sure, as it will take time to see how events unfold.
“Drug-dispensing contact lens effectively lowers eye pressure in pre-clinical glaucoma model,” Massachusetts Eye and Ear web site, August 29, 2016; http://www.meei.harvard.edu/news/press-releases/2016/08/drug-dispensing-contact-lens-effectively-lowers-eye-pressure-in-preclinical-glaucoma-model, last accessed August 30, 2016.