Light-emitting contact lens could prevent diabetes-related blindness
Low light levels produced by tritium-filled light vials in the lens could prevent diabetic retinopathy.
Apr 24th, 2018
(Image: Caltech) A contact lens containing small light-emitting vials of tritium and phosphor could, though its low levels of light emission through the night, prevent diabetic retinopathy, a form of blindness that can arise in advanced stages of diabetes. Existing treatments for this type of blindness painful and invasive, involving laser surgery or injections into the eyeball. Created by researchers at the California Institute of Technology (Caltech; Pasadena, CA), the lens works by producing just enough light to reduce the retina's night-time oxygen demand by giving the rod cells the faintest amount of light to look at while the wearer sleeps. The lenses thus reduce the metabolic demands of the retina. The loss of vision that accompanies diabetes is the result of damage the disease causes to small blood vessels throughout the body, including those in the eye. That damage results in reduced blood flow to the nerve cells in the retina and their eventual death. As the disease progresses, the body attempts to counteract the effects of the damaged blood vessels by growing new ones within the retina. In diabetes patients, however, these vessels tend to be badly developed and bleed into the clear fluid inside the eye, obscuring vision and compounding eyesight problems. As the blood vessels bleed, they cause additional damage to the retina that the body repairs with scar tissue rather than new light-sensing cells. Over time, a diabetic patient's vision becomes blurry and patchy before fading away completely. Because damage to the retina begins with an insufficient supply of oxygen, it should be possible to stave off further eyesight loss by reducing the retina's oxygen demands. Until now, that's been achieved by using a laser to burn away the cells in the peripheral parts of the retina, so the oxygen those cells would have required can be used by the more important vision cells in the center of the retina. Another treatment requires injecting medication that reduces the growth of new blood vessels directly into the eyeball. Clearly, the light-emitting contact lens would be a much less unpleasant approach. "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," says lead researcher and Caltech graduate student Colin Cook. The team recently took their invention to TigerLaunch, an entrepreneurship competition hosted by Princeton University. Their work was recognized as the top medical technology, and the team came in third place overall. Source: http://www.caltech.edu/news/glowing-contact-lens-could-prevent-leading-cause-blindness-82050