Picture trying to ski after staring directly at the sun. Bushes blend into the snow. Turns become an illusion; one second they are there and the next they are not. If it sounds somewhat impossible, consider it’s the field of vision Canadian Paralympic cross-country skier Brian McKeever has had for the past 19 years of his professional cross-country career. “If you stare at the sun for a long time and turn away, you get these...