December 10, 2013
Drug-Releasing Contact Lens Effectively Treats Glaucoma
Ranjini Raghunath for redOrbit.com - Your Universe Online
A contact lens that slowly releases drugs into the eye to treat glaucoma has been developed by researchers at MIT, Boston Children’s Hospital and Harvard Medical School. The lenses provide a sort of 'hands free' alternative to medicated eye drops or more expensive treatments such as laser surgery for treating glaucoma.
Glaucomas are eye disorders arising from build-up of pressure on the optic nerve which acts as a bridge between the eye and the brain. Glaucomas affect more than 60 million people worldwide. Unless treated, they can lead to permanent blindness. There is currently no cure, but early diagnosis and treatment can control or prevent blindness in patients.
Taking eye drops containing drugs to reduce fluid build-up is the most common and efficient treatment method, but it has some drawbacks. Only a fraction of the drug actually gets absorbed; the rest enters the nasal passage or spills over, causing irritation to the skin. Sometimes patients simply forget to take their eye drops regularly. Overall, less than 50 percent of patients who use eye drops stick to it, the researchers wrote in their paper, which appeared in the journal Biomaterials.
For fifty years now, contact lenses that release drugs periodically into the eyes have been explored as an alternative treatment option. However, those developed so far can only release the drug for a few hours after first use.
The newly developed contact lens, on the other hand, can deliver large quantities of the drug constantly for at least four weeks – the longest any lens has been able to do so far, the researchers wrote. The lens eliminates the need to keep track of and take eye drops daily, and needs to be changed only once a month.
The lens consists of a thin film of FDA-approved polymer and latanoprost – the drug used in eye drops – entrapped along the sides of a regular contact lens, enabling controlled release.
For at least a month, the lenses were able to release the drug at amounts similar to that taken by the patient daily in the form of eye-drops. The researchers also tested for any toxic or allergic reactions arising from breakdown of the lens material or the drug and found none. Neither the lenses nor the drug harmed cells grown in the lab or animals, they wrote.
The lenses can be made to custom specifications commonly used for correcting short or long sight. They can also be tailor-made to release antibiotics or drugs used for other eye infections, the researchers believe.
"A non-invasive method of sustained ocular drug delivery could help patients adhere to the therapy necessary to maintain vision in diseases like glaucoma, saving millions from preventable blindness," Joseph Ciolino, Massachusetts eye specialist and first author, said in a statement.