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The Eyes Have It
Detecting infant vision problems
While many vision problems begin in early infancy or
before, they often are not recognized until a child
has reached school age, when it may be too late to
correct the problem.
Sight and the brain
In infancy and throughout the preschool years,
seeing is understanding. More than 75% of infant
learning occurs through the eyes: children learn
what to do, and how to act, by watching others.
Learning to read facial expressions and body
language, and to respond appropriately, takes place
in these early years. What children observe through
their eyes forms much of the foundation of their
social communication skills.
During these first years, a child’s rapidly
developing brain responds to its environment,
turning on and off capacities according to the
various demands the body makes on it. If, for
example, a child is less able to focus with one eye
than the other, as in amblyopia, or “lazy eye” (a
condition affecting 3–5% of all children), the
child’s stronger eye becomes dominant. Gradually the
child’s brain loses its ability to interpret
visional information from the weaker eye. Without
early detection and intervention—by patching the
stronger eye so that the child uses and strengthens
the weaker eye—irreversible vision loss can occur.
Asking before being told
To prevent potential vision loss or resulting delays
in cognitive and social development, it is vital to
know if an infant’s vision is developing normally
and, if not, to take steps to resolve the problem as
soon as possible. Early detection provides the best
opportunity to repair problems and prevent permanent
changes.
Unfortunately, babies can’t tell us when they don’t
see properly. Even highly verbal preschoolers who
tell their parents everything may not say a word
about poor vision. Young children know only what
they see, rather than what they “should” see. A
child assumes that the world sees as he does, not
realizing that everyone else sees the leaves in the
trees, rather than large fuzzy green balls. How can
vision problems be detected in very young children
who can’t yet talk, read, or understand that they
see differently?
Screening methods
The first step in examining an infant or toddler’s
vision is to review the baby’s family history of
vision problems for potential genetic issues.
Pediatricians then perform a thorough external
examination of the eyes and eyelids. Vision testing
includes a series of exercises, such as following a
dot of light, to ensure that the eyes are aligned
and the lenses are not blocked.
If an initial screening suggests that a child is at
risk for vision problems, pediatricians may refer
families to an ophthalmologist for further
evaluation. These eye and vision specialists may
employ ocular photoscreening, an alternative testing
method for children who cannot read an eye chart or
sit still long enough for physical testing. This
method measures a child’s visual reflexes and eye
alignment. A preverbal child simply needs to fixate
on the appropriate target for a few seconds for the
photoscreening process to take place.
Another emerging technology that holds promise for
wide-scale testing of infants and other nonverbal
and preliterate children is the Pediatric Vision
Screener (PVS). This recently developed screening
instrument verifies the ability of both eyes to
focus on a target at the same time. Children between
2 and 4 years old with lazy eye or other issues can
have the problem detected in this way long before
they are able to tell us and in time for the problem
to be repaired successfully. The device is now being
tested with children as young as 12 months.
Screening for all
While these screening technologies continue to
develop, wide-scale efforts to screen all toddlers
and preschoolers for vision problems are underway.
Whether screening is performed in a pediatrician’s
office or at a childcare center or preschool, it is
essential that parents insist on early and regular
assessments for their young children.
Sources: Pediatrics 109 (2002): 524–25; Pediatrics
105 (2000): 1292–98; Insight 30 (2005): 17–20;
American Academy of Pediatrics Policy Statement
(2003): 860–65; Journal of Pediatric Ophthalmology
and Strabismus, 42 (2005): 103–11.
SIDEBAR:
All too common
Vision disorders are the fourth most common
disability among children in the United States and
the leading cause of impaired conditions in
childhood. Recent studies estimate that only 21% of
all preschool children are screened for vision
problems, and only 14% receive a comprehensive
vision exam. Eye exams are recommended for all
children beginning in the newborn period and
continuing with every checkup.
Source: American Academy of Pediatrics,
www.medicalhomeinfo.org/screening/vision.html
What causes poor vision?
Vision impairment can be caused by any damage to the
eye that affects its ability to receive or process
visual information. Poor vision can be due to the
eye being shaped incorrectly, which can make it
harder to focus on things. It can also occur
if the brain does not process visual information
correctly. Vision problems can occur anytime during
a person’s life, even before birth. Poor vision in
children under the age of 10 years is most commonly
due to premature birth, as children who are born
very early, or who have very low birth weight, are
most at risk for retinopathy of prematurity, an
abnormal blood vessel growth or scarring of the
retina of the eye.
The Parent Review newsletter publishes the latest
research findings in child development, learning,
and health. Written for expectant and new parents
and the professionals supporting them, The Parent
Review bridges science and parenting to offer the
best and most relevant research-based news. To learn
more, visit
www.theparentreview.com .
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