In the gospel of Matthew, chapter 25, Jesus says: "I was hungry, and you gave me food to eat; I was thirsty, and you gave me drink; I was a stranger, and you took me in; naked and you clothed me; I was sick, and you visited me. I was in prison, and you came to me."
When people ask Christ when they had seen him in such dire conditions, he responds, "Inasmuch as you did it to the least of these my brothers, you did it to me."
More than 15 years after that Bible study class, Caudill has traveled to Central and South American countries to help people who have eye problems but have little access to the care they need.
"I really believe this is a calling," said Caudill, a member of Morris Memorial United Methodist Church in Charleston. "I get a great deal of satisfaction from helping people."
An ophthalmologist, Caudill has a practice at Charleston Eye Care. But he volunteers through Medical Ministry International, a nonprofit group dedicated to bringing health care to those in need around the world. The ministry only goes where they're invited.
Staff with the Medical Ministry help set up clinics so that when the volunteers arrive, they can go straight to work. "The patients are waiting for us when we arrive," Caudill said.
With his years of experience, Caudill was selected to serve as medical director for a team going to Mexico this summer. In two weeks, he and other team members saw 1,000 patients.
The doctors bring equipment with them and pay their own airfare to travel.
At the end of the day, Caudill said, the volunteers' backs and necks ache. They don't get to work in air conditioning.
But Caudill watched as a woman who had just received care started to walk away, then paused to give "a beaming smile" to Dr. David Bernitsky, a volunteer doctor from New Mexico.
"I said, 'David, there's your payment for today.' That smile gives you a real satisfaction," Caudill said.
Many people who require his care have cataracts, but most of the cataracts removed in Mexico were thicker than the ones he removes in his Charleston practice. The cataracts grow thicker while people wait longer for care.
When doctors remove the cataracts, they implant a lens, which is donated along with other supplies by Alcon Laboratories Inc.Caudill says the numbers of people with cataracts are increasing around the world, and there is a backlog of people who need care. Medical Ministry International needs more volunteers as well.
He's taken his wife Gloria and his four children on several trips. He knows a little Spanish, and his youngest child has learned the language.
"They enjoyed it. I think it has given them a different perspective on the world, when they see people in such need," he said. "I think it has also made them a little less materialistic knowing how other people live."