Here's why Olympic sharpshooters wear those weird glasses

If you've caught any of the sharpshooting events at the Rio Olympics, you've probably noticed most athletes donning very strange-looking glasses.

Turns out the high-tech specs are critical to a shooter's accuracy, Wired reports.

Though the glasses are extremely customizable, most pairs contain three basic elements: a lens, a mechanical iris, and blinders. These components work together to help shooters focus on both the faraway target and their gun's sights at the same time.

This is a lot harder than it sounds: Hold up a finger at arm's length, then try to focus on both your finger and something on the other side of the room. Not easy.

The clear lens has a slight prescription correction, which helps the shooter focus on the gun sights.

Then, there's the mechanical iris, usually mounted right behind the lens. It limits the amount of light that enters shooters' eyes, enabling them to focus on both the faraway target and the gun sights at the same time.

Wired compares the concept to squinting to see something far away: Making your eye opening smaller helps you focus better.

This concept is also seen in photography.

All cameras have a setting called aperture, and adjusting it changes the amount of light that enters the camera. When the aperture is the smaller, there's less light going into the camera, and photographers are able to focus on objects both near and far.

Since human eyes are similar to cameras, the practice works for us, too.

Finally, the blinders block out movements that could distract shooters.

The glasses have become standard for elite shooters."Pretty much everybody uses them these days," gunsmith Scott Pilkington told Wired. "They want every little extra edge they can get."