Like the ability to hear, the ability to see helps determine how people perceive and interpret the world. Vision is important to our ability to communicate as well as to our physical health, independence, mobility, social and community participation, education and employment, socioeconomic status, and performance of activities (National Academies of Sciences, Engineering, and Medicine [NASEM], 2016). Vision has a crucial role in every aspect of life. It is a critical component of personal encounters in which information is often shared through nonverbal cues such as gestures, facial expressions, and body language (World Health Organization [WHO], 2019b). In one survey, more than 70% of respondents identified loss of vision as one of the most feared health outcomes (National Eye Institute [NEI], 2019b).
Vision is essential to child development from a very early age— when infants begin to visually recognize and respond to parents, family members, and others. It plays a role in the cognitive and social development of infants and young children, as well as in the development of motor skills, coordination, and balance (WHO, 2019b). Vision is important in education, friendships with others, self-esteem and well-being, and participation in sports, physical activities, and social activities recognized as essential to physical development and to mental and physical health.
Vision loss and blindness can hamper the performance of everyday activities, including walking, reading, caring for others, and functioning in the world. In a world based around the ability to see, vision impairment can have significant consequences for people, their families, and those who provide healthcare (WHO, 2019b).
Vision plays a role in people’s personal identity and socialization. With impaired or no vision, these can be negatively affected.
NASEM (2016) describes vision loss as the result of physiological changes or structural, neurological, or acquired damage to the structure or function of one or both eyes or to visual information processing structures in the brain. According to the World Health Organization (WHO, 2019b), disability due to vision loss is an impairment, limitation, or restriction that individuals with vision loss experience in their interaction with the physical, social, or attitudinal environment.
A WORD ON THE TERM VISION LOSS
The term vision loss suggests a decrease in visual ability and function. However, some people with congenital or very early blindness do not perceive vision impairment as a loss. This view could affect their willingness to accept treatment to improve or even reverse impairment. Still, this chapter uses the term vision loss, along with vision impairment. Neither term is intended to exclude or offend those who are blind from birth or who became blind later in life.
There is no universal definition of vision impairment. NASEM (2016) defines it as a measure of the functional limitation of one or both eyes or of other parts of the visual system that results from vision loss. The Centers for Disease Control ...