An estimated 285 million people live with visual impairment worldwide, 39 millions of which are blind. While, the majority of the visually impaired population live in developing countries, the Royal National Institute for the Blind (RNIB) estimate there are approximately 2 million people living with varied severity of sight loss in the UK. With growing age population in the UK, it is estimated that the number of people living with sight loss in the UK would double by 2050.
Vision impairment is defined as a limitation of one or more functions of the eye; visual acuity (clarity of vision) or visual field (central or peripheral vision loss). Vision impairments can be temporary or permanent. For example, as a result of an infection or an accident, a person can be temporarily visually impaired while they are being treated, or diseases which cause permanent loss of vision such as Age-related Macular Degeneration (AMD), cataracts, diabetic retinopathy, and glaucoma.
Vision loss affects people’s ability to independently manage their day to day lives. As a result of this dependence on others, many people with vision loss are unable to go out by themselves and become isolated from their social environment. An RNIB survey reported that over a three month period, 30% of the respondents experienced injuries where they collided with street furniture or A-boards outside shops. As a result, almost half of the blind people surveyed did not feel confident going out on their own and felt isolated from their community. Restricted outdoor mobility has been linked with the feeling of loneliness and isolation in elderly blind individuals. Roadworks and crowded commercial streets are particularly stressful to navigate as they restrict a blind person’s ability to navigate the pavements safely.
Navigation is a process of moving from one point to another using landmarks and clues as reference to develop a mental map of the route. Vision plays a critical role in navigation as majority of the spatial information is gathered through visual perception. In the absence of visual perception, orientation and mobility (O&M) skills, mobility aids such as long canes and guide dogs, and navigation technologies are used to identify visual landmarks and clues and navigate the route. Many BPS individuals use sound, touch, and olfactory cues to identify routes and gather spatial information about the environment.
Large open spaces present new set of challenges for blind navigation due to unique layout of the space. O&M techniques rely on built infrastructure references (e.g. building wall, kerb, etc.) for successful navigation. The lack of these landmarks makes it difficult for blind individuals to navigate large spaces independently. A large number of mobile apps and devices are now available that assist navigation in outdoor spaces using turn by turn navigation instructions but most of these apps and devices depend on the user’s visual perception to assess the environment and follow instructions.
Assistive technologies such as mobile map apps have helped to empower people with visual impairments by providing turn-by-turn instructions to navigate built-environment. Extensive research has been done to improve accessibility of urban spaces and mobility of blind individuals through navigation technologies in indoor and outdoor urban spaces. But, we know very little about how blind people use open spaces such as public parks, nature reserves, and forests.
In my research, I aim to explore the navigation strategies that can be effective in navigating open spaces and how assistive technology can help improve the experiences of people with visual impairment.