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Hearing and Vision Deficits

Hearing and Vision Deficits . Vision Numbers. Estimates vary as to the number of Americans who are blind and visually impaired. According to one estimate, approximately 10 million people in the United States are blind or visually impaired.

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Hearing and Vision Deficits

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  1. Hearing and Vision Deficits

  2. Vision Numbers • Estimates vary as to the number of Americans who are blind and visually impaired. • According to one estimate, approximately 10 million people in the United States are blind or visually impaired. • Other estimates indicate that one million adults older than the age of 40 are blind, and 2.4 million are visually impaired. • Over the next 30 years, as the baby-boomer generation ages, the number of adults with vision impairments is expected to double. • Recent figures also indicate that only 46% of working-age adults with vision impairments and 32% of legally blind working-age adults are employed.

  3. What is Vision impairment? • "vision impairment" to mean that a person's eyesight cannot be corrected to a "normal level.“ • Vision impairment may result in a loss of visual acuity, where an individual does not see objects as clearly as the average person, and/or in a loss of visual field, meaning that an individual cannot see as wide an area as the average person without moving the eyes or turning the head. • Vision impairment can occur at any time in life, but as a person's age increases, so does the likelihood that he or she will have some form of vision impairment.

  4. Types of Vision deficits • Nearsightedness • The lens causes light rays from distant objects to converge in front of the retina, which blurs the image • Farsightedness • the lens causes light rays to close objects to converge behind the retina

  5. Blindness • Blindness is usually considered as an inability to see or a complete loss of vision, although legally, a blind person may retain some vision. In contrast, visual impairment indicates a loss of vision such that there is an impact on daily living, which usually implies partial loss of vision. Color blindness • Originate from the lack of one or more type of cones. Total color blindness (monochromatic vision) is very rare; most commonly various levels of single color deficits are found

  6. Causes • There are many causes of visual impairment or blindness, and all parts of the eye (cornea, retina, lens, optic nerve) can be affected. • The causes can be genetic (inherited eye diseases affecting both eyes) • accidental (mechanical injury to the eyeball) • inflammation of the eye tissues • acute or extended exposure to harmful chemicals or radiation (acids, tobacco smoke, UV radiation) • dietary imbalance (lack of vitamin A) • medication • systemic diseases (diabetes) • simply an aging process.

  7. Hearing • Hearing loss can be categorized by which part of the auditory system is damaged. • There are three basic types of hearing loss • conductive hearing loss • sensor neural hearing loss • mixed hearing loss

  8. Conductive hearing loss • occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones of the middle ear. • Conductive hearing loss usually involves a reduction in sound level or the ability to hear faint sounds. This type of hearing loss can often be corrected medically or surgically. • Some possible causes of conductive hearing loss: • Fluid in the middle ear from colds • Ear infection • Perforated eardrum • Benign tumors • Impacted earwax • Swimmer's Ear Presence of a foreign body

  9. Sensorineural hearing loss (SNHL) • occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. • cannot be medically or surgically corrected. • This is the most common type of permanent hearing loss. • SNHL reduces the ability to hear faint sounds. Even when speech is loud enough to hear, it may still be unclear or sound muffled. • Some possible causes of SNHL: • Illnesses • Drugs that are toxic to hearing • Hearing loss that runs in the family (genetic or hereditary) • Aging • Head trauma • Exposure to loud noise

  10. mixed hearing loss • Sometimes a conductive hearing loss occurs in combination with a sensorineural hearing loss (SNHL). • In other words, there may be damage in the outer or middle ear and in the inner ear (cochlea) or auditory nerve.

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