Define deafblindness using the text:


Context: Deafblindness is the condition of little or no useful hearing and little or no useful sight. Different degrees of vision loss and auditory loss occur within each individual. Because of this inherent diversity, each deafblind individual's needs regarding lifestyle, communication, education, and work need to be addressed based on their degree of dual-modality deprivation, to improve their ability to live independently. In 1994, an estimated 35,000–40,000 United States residents were medically deafblind. Helen Keller was a well-known example of a deafblind individual. To further her lifelong mission to help the deafblind community to expand its horizons and gain opportunities, the Helen Keller National Center for Deaf-Blind Youths and Adults, with a residential training program in Sands Point, New York, was established in 1967 by an act of Congress.

The deafblind community has its own culture, comparable to those of the deaf community and the blind community. Members of the deafblind community have diverse backgrounds but are united by similar experiences and a shared, homogeneous understanding of what it means to be deafblind. Some deafblind individuals view their condition as a part of their identity.

Answer: Deafblindness is the condition of little or no useful hearing and little or no useful sight.