Lack of Visible Disability

It is on rare occasion that you will see an Korean here with a visible handicap. When you see someone who is in a wheelchair, has a disfigurement or is somewheres on the autism spectrum, you are quite taken aback. The area either does not have as many people in this category as we do back home OR they are not allowed to be in the public eye. I gather that the later is true. If you are not good enough here, you are not allowed out it seems.