Piloting a bobsled is no simple task. Over 600 kilos of steel, fibreglass and human flesh hurtling down an icy chute, it can’t be steered in any conventional sense, and the brake is only useful once you’ve made it to the bottom of the hill. Learning how to guide one—as safely and as fast as possible—takes years of bruising practice. Although surprisingly, actually being able to see the track isn’t necessary for success.

Holcomb was an up-and-coming driver for the U.S. bobsled team when he was diagnosed with keratoconus, a progressive thinning of the cornea that can ultimately lead to blindness. But told that it would be years before his eyesight failed, and fearful of the potential fallout for his Olympic dream, he declined to make his condition known. It turned out to be a poor decision. Holcomb’s vision deteriorated much more rapidly than predicted. Within a couple of years he couldn’t see across a room, let alone down a track. And when he was named to Team USA for the 2006 Turin Games, he only passed the vision test by memorizing the eye chart. Continue…