It is possible for blind, deaf, or disabled people without hands or legs who can think wisely to realize Buddha’s teachings. Therefore, a blind person who can think well can still be able to realize Dhamma after listening to it. If a person was not born deaf, but become deaf after some time, that person will realize Dhamma if he can understand Dhamma by reading it. Let us say that someone was born disabled, but can see and hear. Then, that person can stop the birth which can leads to more of such miserable lives without hands or legs by understanding Dhamma.