As Roland moves along, he encounters many among the border dwellers. An increasing number of them live alone and fall into two categories--lepers or madmen. Roland claims to find the madmen better company.
One, for example, gave him a Silva compass and asked him to pass it along to the Man Jesus. Although Roland doesn't expect to see the Man Jesus, either in his travels or anywhere, he takes the compass fully intending to do as the madman requested should the opportunity present itself. The fact that our gunslinger is given a compass is an interesting irony, of course, and I'm insanely curious as to whether or not the compass even works.
I'm even more intrigued by the presence of lepers.
Leprosy is part of recorded history since 600 BC. It's a progressive disease where skin lesions cause serious damage to a person's body. Leprosy was treatable on a limited basis as early as the 1930s and has been effectively curable since the early eighties. That leprosy still exists in Roland's world demonstrates that either his location mirrors that of a third world country, where a disease like leprosy is still a problem more than twenty years after it ceased to be an issue in "civilized" nations, or that the disease was never cured in Roland's when.
It's impossible not to notice the Biblical allusions that show up throughout The Dark Tower. The idea of lepers living alone and forgotten is more than reminiscent of the Bible. It's more than a coincidence. It's yet another hint that this tremendous work is more Biblical in nature than most people would believe.