Foundation Fighting Blindness raises money for research into the spectrum of retinal degenerative diseases and provides resources for patients and their families.
The foundation has raised more than $350 million since 1971 and currently funds 151 grants at 80 institutions.
More than 10 million Americans are affected by retinal degenerative diseases like retinitis pigmentosa, macular degeneration and Usher syndrome.
Age-related macular degeneration, characterized by a progressive loss of central vision, is the leading cause of blindness in adults older than 55.
For more information, visit fightblindness.org.
Legally blind, Michael Stone can distinguish -- just barely -- between light and dark.
That hasn't stopped the Boulder endurance athlete and coach from completing 10 Iron Man triathlons and eight XTERRA off-road triathlons. Relying on directions from his friend and guide Jared Berg and his intuition from thousands of hours of running and cycling, he barrels down rocky slopes.
It is both terrifying and invigorating, he said.
"It's fear management," he says of these intense competitions. "It also makes me feel more alive."
Stone has cone-rod dystrophy, an inherited, degenerative disease that causes color blindness, night blindness and eventually the loss of most vision except for some light awareness.
Stone, 42, didn't see well for most of his life, but he wasn't diagnosed until 2006. He now is legally blind.
He already was an endurance athlete, having completed his first triathlon in 2001.
He had moved to Boulder from his native Illinois to be outdoors, and he was determined to keep running, riding, swimming and skiing.
Stone used to build and manage hotels and resorts before his vision worsened.
Now, he works as a performance coach and personal trainer with Stepping Stone Sports, mostly for people who face some sort of challenge.
Stone is also an author. He recently self-published "Eye Envy," a collection of interviews with people who had lost their vision and continued to live rewarding lives.
"When I first got my diagnosis, I was feeling isolated and alone and a little freaked out," Stone said. "I figured I'm not the first person to deal with this. I went out and found all these people who had dealt with losing their vision and gone out and lived normal lives."
He sees the book as a guide that can give perspective to patients and their families.
Proceeds from the book go to the Foundation Fighting Blindness.
Berg, a friend of Stone for the last decade, serves as his guide, verbally directing him over rocky trails and steep descents. The two traveled in the same circle of friends and did the same types of training, but their connection deepened when Stone asked Berg to take him cross-country skiing at Eldora Mountain Resort.
Berg got a glimpse of what Stone saw -- and didn't -- and how that affected him in motion when their trail crossed a fire line and Stone wanted to turn down the opening in the trees.
Berg said it's been rewarding to watch Stone develop his abilities. He said Stone is a better rider, with faster reactions and more control, even as his sight has worsened.
"His sight is worse, but he's a better rider," Berg said. "He's slower on the downhills. I can tell that's he's thrown off. But he's faster on the uphills because he has better control."
At the end of a race, Berg's main feeling is relief.
"It's like I just took a test," he said. "I studied, and it went well, and now I'm done."
He feels proud of Stone, but also responsible for him. His greatest fear is that a misspoken or misunderstood direction, a hesitation or miscommunication in any of the thousands of calls he makes over the course of a ride, will cause Stone to make a dangerous error.
"I don't want any of the decisions I made or let him make to affect him adversely," he said.
The lighting can make a big difference for Stone. If it's a cloudy day with no contrast, he "might as well have a blindfold on." But his condition creates an effect as if flashlights were shining straight into his eyes, and he wears sunglasses to reduce glare from bright light.
"Light is my best friend and my worst enemy," Stone said.
He can confidently run or bike up a volcano, but he twice walked into the screen door of his hotel room in Hawaii.
"My greatest competition is myself," he said, though he was quick to add, "It's not like I'm slow."
At an XTERRA event earlier this month, he finished in four hours, six minutes and 58 seconds and placed 324 out of 501 competitors. He placed second in the physically challenged division.
One frustration is that he cannot push himself to the limits of his physical abilities because of the limits on his vision. He and his guide both need enough breath to talk, and going too fast increases the risk of a misstep on the trail.
"I don't want to take unnecessary risks," Stone said. "I have to keep that in the back of my mind. You want to push, but not too much, and that's a fine balance."
Stone said events leave him emotionally drained, which also takes a physical toll. At the same time, the rush of adrenaline and the sense of accomplishment from completing a course are intense.
"It's like, oh my God, I just did that, and I didn't even see it," Stone said. "Other people might not even realize what they just did."