A 26-year-old founded a medical startup — the same year he lost almost half his vision

As a rifleman in the Republic of Korea Marine Corps who endured harsh training as part of his national service, Kevin Choi had “no doubt” about the state of his health. 

“I’ve got quite severe myopia, but I still believed I was very healthy,” Choi told CNBC Make It.

But all that changed in 2016, when he discovered he had glaucoma — a chronic, progressive eye disease caused by optic nerve damage.

While glaucoma is more common in older adults, Choi was only 26 when he was diagnosed. 

By then, Choi said he had already lost half of his right eye vision, and only had about “60% to 70%” of his left eye vision left — something which could have been avoided with early detection. 

But in the same year, he rose above these adversities by launching his own health-care startup, Mediwhale. 

Its devices assess cardiovascular risk through the use of retinal imagery and artificial intelligence — a first of its kind, Mediwhale told CNBC Make It.

With starting capital of $5,000, he launched the startup with his ophthalmologist, Dr. Tyler Hyungtaek Rim six years ago.

Today, the company said it has raised millions from investors, with its devices approved in the EU and several countries in Asia. 

How did an advanced glaucoma diagnosis propel Choi to start his own company? CNBC Make It finds out.