Facts on File Encyclopedia of Health and Medicine

• eyeglasses (polycarbon lenses for optimal pro-
  tection against shattering)


• working with power tools


• exposure to environment with high airborne
  pollutants (such as sawdust)

Though regular eyeglasses and sun-

glasses provide some protection against

injury, they do not provide adequate

protection when working with power

tools, during recreational and athletic

activities, and for specialized needs

(such as welding).

Regular Ophthalmic Examinations

In the United States, basic screening for eye prob-
lems takes place shortly following birth (for
infants born in hospitals and birthing centers), at
regular well-child check-ups, through public
school vision screening programs, and as part of
the ROUTINE MEDICAL EXAMINATION. People who have
normal vision require only ophthalmic examina-
tions, the need for which becomes more frequent
with advancing age as the likelihood of health
conditions that affect vision increases with age.
People who have eye conditions, REFRACTIVE
ERRORS, HYPERTENSION, DIABETES, and other chronic
health conditions need regular ophthalmic exami-
nations as their physicians or eye care providers
recommend.
See also CORRECTIVE LENSES; OPHTHALMIC EXAMINA-
TION; 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 require-

ments 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 perma-

nent.

LEGAL BLINDNESS

VISUAL ACUITYuncorrectable to 20/200 in the better eye, or

VISUAL FIELDuncorrectable 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 pro-

grams. The diagnostic path for children in whom

screenings detect potential vision problems

includes a complete OPHTHALMIC EXAMINATIONwith

testing for visual acuity, REFRACTIVE ERRORS, and

visual field as the child’s needs require. Eye care

specialists use assessment methods appropriate for

122 The Eyes

RECOMMENDED ROUTINE EYE EXAMS

Age Eye Exam Frequency
Birth to 2 years screening at well-child visits
3 to 5 years screening every one to two years at well-child visits
6 to 19 years screening at routine medical exam; ophthalmic exam as needed
20 to 29 years ophthalmic exam once during this time
30 to 39 years ophthalmic exam every five years
40 to 65 years ophthalmic exam every two years
65 years and older ophthalmic exam every year