Comfortably leading the race as she entered the last 12 miles, her vision began clouding from the periphery. Temporary distorted vision isn’t unheard of in ultra-running; the stress of running so hard and long can mean the body struggles to refresh the fluid in the eyeball as usual. It is a condition known as corneal edema. But Dauwalter’s case was particularly severe. As she continued towards the finish line, it worsened until she was effectively 90% blind.

…

Dauwalter made it to the aid station, but instead of dropping out, she used a volunteer to guide her by narrating the terrain as they ran. A battered and bleeding Dauwalter crossed the finish line - the first woman to do so that day - in 20 hours 38 minutes 09 seconds, external with her vision returning to normal five hours later.

Wtaf. That is freaking amazing.