Definition of Vision Impairment

Vision Impairment – the uncorrectable loss of vision. About 12 million Americans have vision impairments that prevent them from participating in occupations and activities that have requirements or legal standards for visual acuity (the ability to see clearly) and visual field (the scope of peripheral vision).

People who have functional vision, also called low vision, generally have visual acuity correctable to between 20/40 and 20/400. More than a million Americans are legally blind. Vision impairment may be temporary or permanent.

Legal Blindness

Visual acuity uncorrectable to 20/200 in the better eye, or visual field uncorrectable to greater than 20 degrees

Symptoms and Diagnostic Path

In children, the symptoms of vision impairment may be difficult to detect. Those that are obvious include:

  • Strabismus, which indicates amblyopia
  • Squinting
  • Holding objects very close to the face
  • Sitting very close to the television
  • Frequent headaches

Routine screening for eye and vision health takes place at birth (for infants born in hospitals and birthing centers), during routine well-child visits, and through school vision screening programs.

The diagnostic path for children in whom screenings detect potential vision problems includes a complete ophthalmic examination with testing for visual acuity, refractive errors, and visual field as the child’s needs require. Eye care specialists use assessment methods appropriate for the child’s age, comprehension, and communication abilities.

Recommended Routine Eye Exams
AgeEye Exam Frequency
Birth to 2 yearsscreening at well-child visits
3 to 5 yearsscreening every one to two years at well-child visits
6 to 19 yearsscreening at routine medical exam; ophthalmic exam as needed
20 to 29 yearsophthalmic exam once during this time
30 to 39 yearsophthalmic exam every five years
40 to 65 yearsophthalmic exam every two years
65 years and olderophthalmic exam every year

Sudden loss of vision in one eye or both eyes is an emergency that requires immediate medical care.

Adults are generally able to perceive symptoms of vision impairment, though when onset is gradual the symptoms are less obvious (though may be more apparent to co-workers, friends, and family members). Sometimes the first indication of a serious vision impairment comes with a misfortune such as a motor vehicle accident, especially among older adults who do not notice or do not acknowledge diminishing vision. Symptoms of vision impairment include

  • Dimness or changes in color perception
  • Need to hold objects closer or farther away from eyes
  • Frequent headaches or squinting
  • Loss of sharpness or clarity of vision
  • Difficulty reading
  • Difficulty seeing at night or in low light
  • The need for bright lighting

The diagnostic path includes a comprehensive ophthalmic examination to assess visual acuity, visual field, and refractive error as symptoms indicate. Further diagnostic procedures may be necessary when the underlying cause of vision impairment appears to be a health condition other than a problem with the eyes, such as multiple sclerosis or diabetes.

age-related macular degeneration (armd)albinism
congenital cytomegalovirus (cmv)central serous retinopathy
congenital disorderscorneal deterioration
genetic disordersglaucoma
infectionmultiple sclerosis
retinal detachmentretinoblastoma
retinopathy of diabetesretinopathy of hypertension
trauma to the eyeuncorrectable myopia
retinopathy of prematuritystroke

Vision Impairment Treatment Options and Outlook

Treatment depends on the cause of the vision impairmentCorrective lenses or refractive surgery typically improve vision in conditions such as severe myopia or astigmatism, even if these measures cannot fully restore normal vision. Surgery is often the solution for vision impairment due to cataractcorneal injury or deterioration, retinal detachment, and some forms of glaucoma. Medications can control other forms of glaucoma.

Vision impairment has a significant effect on quality of life. There are numerous assistive devices for people who have functional limitations as a result of vision impairment.

Most people who have vision impairments are able to participate, with reasonable accommodations and sometimes creative effort, in work and recreational activities they enjoy. Continued advances in technology generate new treatment approaches that may offer improved vision.

Risk Factors and Preventive Measures

Many health conditions can contribute to or cause vision impairment. The most significant are diabetes, hypertension, and glaucoma. Early diagnosis and appropriate treatment can limit or prevent damage to the eyes and to vision. Eye protection, such as sunglasses and safety eyewear for activities with risk for impact or debris, is a key preventive measure.

More than 40,000 preventable eye injuries occur every year. Routine ophthalmic examinations detect eye problems early, allowing for the most appropriate and effective interventions to preserve vision.


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