Marathon runners often rely on partners to pace them throughout the race, but Henry Wanyoike’s reliance is total.

Since losing his sight to a stroke in 1995, Mr. Wanyoike, a 33-year-old Kenyan, has become the dominant athlete in his sport.

His legend began at the 2000 Sydney Paralympics, his first international competition as a blind runner, where took gold in the 5,000-meter race and narrowly fell short of the world record.

“That time I was not with Joseph,” Mr. Wanyoike said of the guide he will be tethered to during Sunday’s New York City marathon, Joseph Kibunja. After finding his guide at the event “a bit slow,” he decided to recruit a trusted childhood friend, Mr. Kibunja, to be his partner. There was, however, a problem: Mr. Kibunja, then 26, had never been a competitive runner.

“I didn’t think I could run even 100 meters because I was not interested in running,” Mr. Kibunja said. “I was scared. But he encouraged me so much each and every day so that I could keep going.”

Mr. Kibunja gained confidence while training with Mr. Wanyoike, and the two set world records in the 5,000- and 10,000-meter races at the 2004 Athens Paralympics. In 2005 in Hamburg, they set the world record for visually impaired marathon running, with an excellent time for even sighted runners, 2:31:31.

“From the time I had my stroke, many friends disappeared,” Mr. Wanyoike said. “But Joseph did not.”

According to Mr. Wanyoike, his greatest challenge in overcoming blindness was others’ doubts. “Many people didn’t believe someone without sight could make it in such a competitive thing,” he said. “And it was quite challenging to get a sponsor.”

Mr. Wanyoike found his sponsor in Standard Chartered Bank, which took him on in 2003 as an ambassador for “Seeing is Believing,” its global initiative to help cure and prevent blindness. The runners are passionately devoted to the cause, which the bank says has raised enough money already to restore the sight of more than 1 million people, with a goal of raising $10 million by 2010.

“We want people to understand what is happening,” Mr. Wanyoike said of his participation, “that this is a noble idea.”

A celebrity in his home country, Mr. Wanyoike says with pride that he has encountered several children there named after him. The champion relishes his status as a role model.

“We are trying to show the world that it is very important to work together,” he said. “On my own I could not be who I am today, but thanks to Joseph, who is my eyes, I have been able to be a world champion.”

He continued: “We are here to show that you can make it even if you have problems. You can make it wherever you are, in whatever profession, despite the challenges. You can still make it if we can make it in this marathon.”