According to a study published in May 2014 by researchers from the University of Copenhagen and Glostrup Hospital, Denmark, blind people’s dreams contain a broader array of sensory inputs, including sounds and tastes — all the senses other than sight that they use to navigate their world.
Out of the five senses, we tend to use sight and sound most, while dreaming. People who were born blind have no understanding of how to see in their waking lives, so they can't see in their dreams. But most blind people lose their sight later in life and can dream visually. Danish research found that as time passes, a blind person is less likely to dream in pictures.
The same research says that people who are born blind have more nightmares than sighted people. The theory is that nightmares are mental rehearsals of potentially distressing events, and they can help develop coping mechanisms. For example, blind people in the study reported dreaming about getting lost, being hit by a car or losing their guide dog.