http://www.hwns.com.au/Resource-centre/Types-of-disabilities/sensory-disability
http://www.onetoonesupportservices.co.uk/Deafblind%20sensory%20impairments%20definitions.htm
https://www.britannica.com/topic-browse/Health-and-Medicine/Diseases-and-Disorders/Diseases-of-the-Senses/2