The glowing contact lens could help prevent blindness in millions of people with diabetes. (Caltech)

Diabetic retinopathy destroys cells of the retina, leading to blindness. Existing treatments are painful and invasive, involving lasers and injections into the eyeball. A Caltech graduate student developed a glow-in-the-dark contact lens that interrupts the process that destroys cells of the retina.

The lenses reduce the retina's nighttime oxygen demand by giving the eye’s rod cells the faintest amount of light to look at while the wearer sleeps. The illumination is provided by tiny vials filled with tritium, a radioactive form of hydrogen gas that emits electrons as it decays. This system ensures a constant light output for the lifetime of the contact lens.