The contact lens that could save millions from blindness

It has been on the cards for nearly fifty years, but technical obstacles have meant that it remained firmly in the realms of science fiction.

Now, however, the 'smart' contact lens that can release medication directly into the eye could finally become a reality. Researchers at Harvard Medical School, Boston Children's Hospital and MIT have developed a contact lens designed to treat glaucoma, the world's number one cause of irreversible blindness.

The lens features a thin polymer film of latanoprost, the most common drug used to treat glaucoma. For the first time, scientists were able to ensure a consistent transfer of medicine to the aqueous humour of the eye - the fluid surrounding the eyeball.

The treatment promises to be significantly better than eyedrops, the current favoured method of administering latanoprost, according to Dr. Joseph Ciolino, Massachusetts Eye and Ear cornea specialist and lead author of the paper: "In general, eye drops are an inefficient method of drug delivery that has notoriously poor patient adherence."

He also hinted that the technology could have wider-reaching applications. "This contact lens design can potentially be used as a treatment for glaucoma and as a platform for other ocular drug delivery applications."

The idea hints at the use of contact lenses for other drugs - a concept seen extensively in sci-fi films, such as Looper, where characters take illegal drugs through their eyes.

"The lens we have developed is capable of delivering large amounts of drug at substantially constant rates over weeks to months," said Professor Daniel Kohane, director of the Laboratory for Biomaterials and Drug Delivery at Boston Children's Hospital.

The lenses are made from the same silicone hydrogel as standard 'soft' lenses, with the medicinal polymer layer added around the edges of the lens. The centre of the lens is clear as usual, ensuring that the treatment does not affect the wearer's vision.

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The lenses can be made with no refractive power, for patients with no need to correct their vision, but it it also possible to embed the latanoprost layer on lenses for short- or far-sighted patients.

The potential of the treatment could be huge, benefiting glaucoma sufferers across the world. 480,000 people in the UK alone suffer from the condition.

"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," Dr. Ciolino said.

Glaucoma occurs when the eye's drainage tubes become blocked, preventing fluid from draining properly. This causes pressure to build up, which can damage the optic nerve connecting the eye to the brain, as well as the nerve fibres from the retina. It typically affects both eyes, and must be treated early before damage is done to the eyes.