Encyclopedia of Health and Medicine

122 The Eyes
• eyeglasses (polycarbon lenses for optimal protection
against shattering)
• working with power tools
• exposure to environment with high airborne
pollutants (such as sawdust)
Though regular eyeglasses and sunglasses
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 problems
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 examinations,
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 examinations
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 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
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