People who experience deafblindness have significant loss of both vision and hearing.
It’s important to understand that this does not mean that they have zero vision and zero hearing (although that’s a possibility).
Blind people generally have some sense of light and dark, but not enough to get by without assistive technology (AT) above and beyond glasses or contacts. On the web, the AT for people with vision loss generally assumes they can listen to content instead.
D/deaf people generally have some sense of sound, but not enough to get by without assistive technology above and beyond hearing aids. On the web, the AT for people with hearing loss generally assumes they can see content instead.
Deafblind people have enough loss of both senses that communication and living skills are impacted significantly — they need more assistance than a D/deaf person or blind person require.
It’s possible depending on the degree of deafness and blindness that a deafblind person experiences that they can use the same AT that someone who is deaf or blind uses. It’s also possible that neither visual nor auditory content on the web is available to them. The AT for someone who is deafblind assumes they can’t count on either their visual or auditory senses, and provides tactile access to content.
When designing for someone who’s deafblind:
- All of the considerations for Blindness and Low Vision apply.
- All of the considerations for Auditory Disabilities apply
- Transcripts are required because captions and voice tracks may not be sufficient depending on the person’s disabilities.
Deaf-Blindness overview by the National Center on Deaf-Blindness.