Study: Smart contact lens could end eye drops misery

By Mark Waghorn via SWNS

A "smart" contact lens could end the misery of eye drops for glaucoma patients.

It measures pressure in the organs - delivering drugs directly on demand.

Project leader Professor Xi Xie, of Sun Yat-Sen University in Guangzhou, China, said: "The device is flexible, wireless and battery-free.

"It has a unique, compact cantilever design, and is minimally invasive - making it highly promising for the treatment of glaucoma."

The condition is the world's leading cause of blindness. It is triggered by "intraocular pressure" inside the eye - which damages cells in the optic nerve.

Prof Xie explained: "This pressure can vary with human activities and circadian rhythm, which makes treatment challenging, as it requires the long term and continuous tracking of the eye's condition."

Daily prescription drops are awkward to use, mixing with tears and running down the face instead of going into the eye.

The lens, called a theranostic, is a potential game changer. It slowly applies the appropriate dose by combining therapeutics and diagnostics.

Prof Xie said: "Electrical sensing measures intraocular pressure. A drug is then delivered on demand through the curved and limited surface of the lens."

Antibiotics could be added - making wearers less vulnerable to bacterial infections than they are with normal lenses.

In experiments, the device detected changes in pigs and rabbits - which have similar eyes to humans.

Prof Xie explained: "The drug delivery module has an efficient circuit that provides electrical power without the need of wires.

"When the intraocular pressure reaches a high-risk level, it has the ability to trigger an anti-glaucoma drug into the anterior chamber of the eye across corneal barriers."

More than half a million people in the UK have been diagnosed with glaucoma. Many more are unaware they have the condition because it is symptomless in its early stages.

It is estimated 3.2 million Britons will be affected by 2050 owing to the aging population.

The eyeball contains a fluid called aqueous humor which is constantly produced, with any excess drained though tubes.

Glaucoma develops when the fluid cannot drain properly and the intraocular pressure builds up.

Studies show one in two patients stop taking eye drops after a year due to forgetfulness or physical limitations like arthritis - leaving them vulnerable to vision loss.

Another problem is about 95 percent of the medication goes where it is not needed - draining into the nasal cavity.

If they get into the bloodstream and travel to other organs, they can cause serious side effects.

Drugs in a contact lens would be released slowly enough to stay in the eye, said Prof Xie.

He said: "Fabrication of the device is compatible with existing large-scale and cost-effective manufacturing processes."

The lens is described in Nature Communications. It is hoped clinical trials will begin after further safety tests have been carried out.

Prof Xie added: "Engineering wearable devices that can wirelessly track intraocular pressure and offer feedback-medicine administrations are highly desirable for glaucoma treatments."