Photos: Equinox marathoner raises awareness for Usher syndrome

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Roger Sayre, left, and Christy Marvin run on the University of Alaska Fairbanks trail system during the Equinox Marathon, Ultramarathon and Relay on Saturday, September 20, 2014. Marvin won the women's marathon and Sayre was the first finisher for his age group.

Fairbanks' Equinox Marathon is widely regarded as one of the most difficult marathons in the nation. Runners endure an 1,800 feet ascent up Ester Dome, racing through wooded trails laced with tree roots and ruts, and over gravel roads before braving a steep descent – sometimes, in the snow.

Think that's hard enough? Now, imagine running it blind.

Brian Switzer will do exactly that on Saturday, when he runs the trail's 26.2 miles in support of the Usher Syndrome Coalition's campaign to "Own the Equinox," and raise awareness for the debilitating disorder.

READ MORE: Blind Fairbanks Equinox marathoner to shine light on rare genetic disorder?