There is no accepted definition of deafblindness to which everyone subscribes. A commonly used definition is:

“Persons are regarded as deafblind if they have a severe degree of combined visual and auditory impairment resulting in problems of communication, information and mobility.” Breaking Through Report (1988)

Deafblindness does not always mean complete sensory loss. Some individuals may retain some residual sight and/or hearing.

Congenital deafblindness

Congenitally deafblind is a term that describes any person who is born with a sight and hearing impairment.

Acquired deafblindness

Individuals may become dual sensory impaired later in life – this is called acquired deafblindness. Those with acquired deafblindness fall into three main groups:

1. People who are born deaf and later lose their sight. This may be as a result of Usher  Syndrome, which is a major cause of deafblindness.

2. People who are born blind and later lose their hearing.

3. People who lose both sight and hearing in later life.


The terms ‘deafblindness’, ‘dual sensory loss’ and ‘combined sight and hearing loss’ are interchangeable.

Usher Syndrome

Usher Syndrome is a genetic condition which causes hearing loss from birth, and a later progressive loss of vision due to Retinitis Pigmentosa (RP). The condition was named after CH Usher, a British opthamologist. There are three types of Usher Syndrome.

Type 1 Type 2 Type 3
Born with a profound hearing loss. Born with a moderate to severe hearing loss. Hearing loss that gets progressively worse over time.
Develop night-blindness in their teens or earlier, due to Retinitis Pigmentosa. Develop night-blindness in their twenties, due to Retinitis Pigmentosa. Develop visual impairment around the age of 20-30 years due to Retinitis Pigmentosa.
Balance problems. No balance problems in childhood. May have balance problems later.