‘Pommel horse guy’ and Olympian Stephen Nedoroscik has two vision-impairing conditions—but that didn’t hold him back from being a champion

If you’ve spent any time on social media in the past 24 hours, you’ve probably run into the viral “pommel horse guy” on Team USA’s men’s gymnastics team, which just won bronze—its first Olympic medal in 16 years. That guy’s name is Stephen Nedoroscik, who executed a pommel horse routine that left his teammates cheering, jumping, and fist-pumping with excitement the second he planted his feet back on the ground.

Seconds before he began the routine, Nedoroscik, 25, removed his eyeglasses, earning him the nickname “Clark Kent” on social media as he transitioned into his competitive alter ego. For Nedoroscik, however, those glasses are what keeps his two vision-impairing conditions at bay: strabismus and coloboma , which he publicly addressed on social media.

“Basically I’m cross-sighted, and I can switch my dominant eye on command,” Nedoroscik said in a TikTok he posted in August 2022, in which he was hoping to get some more info about his conditions from eye doctors online.

Strabismus is also known as eye misalignment, according to the Cleveland Clinic . One eye is turned in a different direction than the other, usually as a result of problems with the muscles that control eye movement. While it’s mainly found in childhood, it is possible for childhood strabismus to remain if it wasn’t treated, or to come back in adulthood.

Around 4% of the U.S., or around 13 million people, have crossed eyes, according to the Cleveland Clinic.

Complications that can arise from strabismus include blurry vision, eye strain, fatigue, headaches, poor three-dimensional vision, and double vision. A lazy eye may also develop, which happens when the brain receives two images from eyes looking in different directions. In an effort to avoid double vision, the brain may ignore what the turned eye sees, causing poor vision development in that eye.

Nedoroscik’s other condition, coloboma, occurs when part of the tissue that makes up the eye is missing. This happens during pregnancy, when a baby’s eye does not fully develop normally.

According to the National Eye Institute, symptoms of coloboma include vision loss or blindness, low vision, and sensitivity to light.

In both cases of strabismus and coloboma, symptoms can be treated with corrective lenses—in Nedoroscik’s case, his Clark Kent glasses. For years, Nedoroscik has been perfecting his pommel horse routine—the only gymnastic event Nedoroscik came to Paris for (thus, the “pommel horse guy” was born), as he watched the rest of his teammates in the other events of the Team All-Around competition. And he did not disappoint his teammates. Outside of gymnastics, Nedoroscik has another talent: solving Rubik’s Cube in 10 seconds or less.

This story was originally featured on Fortune.com