Glow-in-the-Dark Contact Lenses Could Help Prevent Blindness

A Caltech engineer used light therapy technology into a small contact lens in order to delay eye loss caused by diabetes.

For millions around the world suffering from diabetes, eye diseases can be one of the most dangerous and languishing affects of diabetes. All forms of diabetic eye disease -- from glaucoma to diabetic reinopathy -- have the potential to lead to severe vision loss or blindness, according to the National Eye Institute. One engineering student wants to change those odds. 

California Institute of Technology grad student Colin Cook proposed a new way to treat diabetes-related eye diseases in a less-painful and less-invasive way than current treatments. Cook worked alongside other researchers from Caltech's electrical and medical engineering teams to create a unique solution: glowing contact lenses. 

Most diabetic eye issues stem from the disease damaging blood vessels throughout the body but having a significant impact to those within the eye. The change in blood flow to nerve cells lead to those cells dying in the retina. The disease continues staving off blood flow, and the person affected continues to lose their sight. The body does naturally defend itself against this problem. However, diabetes patients tend to have poorly developed vessels attempting to replace the dying vessels. The weakened vessels often bleed clear fluids inside the eye.

Cook noted that the problems largely stem from an insufficient supply of oxygen to the vessels. Thus, he theorized that there could be a new way to reduce the retina's oxygen demands. (Previously, it involved taking lasers to someone's eyeball in order to burn away cells along the outer part of the retina.) 

Cook's contact lenses are significantly less intrusive than the lasers, has fewer side effects, and do the same thing. The lenses reduce the metabolic demands on the retina by monitoring the eye's rod cells. Rod cells help humans see in low-light conditions. They use up considerably more oxygen in dark spaces rather than outside in the sunlight. 

"Your rod cells, as it turns out, consume about twice as much oxygen in the dark as they do in the light," Cook said.

Cook designed the lenses to reduce what the retina needs for it night-time functions by giving rod cells a very faint light to look at while the wearer is asleep. 

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"If we turn metabolism in the retina down, we should be able to prevent some of the damage that occurs," he said.

The illumination on the lense happens thanks to tiny vials of tritium. This radioactive version of hydrogen sends out electroncs while it decays. Those electrons get transformed into light by a phosphorescent coating, guaranteeing that there will always be light throughout the lifetime of a single contact lens. 

There's a growing trend toward light therapy both for the general public and also for sufferers of diabetic retinopathy. Light therapy sleep masks had been a unique and non-invasive option for years. However, the mask would often slip off, causing incoming light to distract a wearer. 

Cook said his lenses place the light source directly on the eye and everything moves together. 

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"There's neural adaptation that happens when you have a constant source of illumination on the eye. The brain subtracts that signal from the vision and the wearer will perceive dark again in just a few seconds," he said.

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According to Cook and his team, the retinas get appropriate light thanks to a strategic lens design. 

"As we sleep, our eyes roll back. For a sleep mask this means the eye is no longer receiving as much light, but the contact lenses move with the eye, so there is no such problem," he noted.

Currently, Cook said he and fellow researchers will be testing lenses for truly preventative measures. In order to test his project, Cook wants to get FDA permits in order to have clinical trials. The project also won top medical technology at TigerLaunch -- a Princeton University entrepreneurship contest. 

"Having our work recognized by a panel of venture capitalists is really exciting," Cook said, "but it was the audience members who came up afterwards and shared stories about loved ones being impacted by the disease who really reinvigorated my efforts."

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