NASA scientists say a tool they developed to help astronauts grow crystals in space could be the key to early detection of cataracts.

It all happened when NASA senior scientist Rafat Ansari’s father developed cataracts. He studied up on the disease and learned that the eye lens is made up of proteins and water. One type of protein, called crystallin, is key to keeping it transparent. But when other proteins are damaged, by elements such as sun exposure or cigarette smoke, the crystallins scoop them up and form clumps that fog the eye.

It just so happened that the laser light Ansari helped develop for NASA measures the proteins that make up crystals. The device is similar to shining a flashlight on dust particles. Large proteins move slowly, smaller ones move quickly.

Ansari found his laser could detect different levels of opacity. Then he presented his findings to medical researchers and asked if they thought the laser could be used to measure the amount of large proteins on an eye lens.

Today, more than a decade later, Ansari’s experiment is now being used. A laser is beamed at a lens for five seconds, then light scattering is calculated to determine if a patient is vulnerable to cataracts.

Don’t call your eye doctor yet. The government only has a few prototypes of the device and no commercial manufacturer is lined up. But someday soon, Ansari hopes his accidental discovery will help millions of others avoid the disease suffered by his dad.