Amblyopia is defined in many dictionaries
as "poor sight, not due to any detectable disease of the eyeball
or visual system", sometimes together with a note of exceptions
i.e. of types of amblyopia for which the underlying dis-ease or causes
are identified or understood.
It may be more helpful to describe amblyopia together
with it's common (layman's) name, which is "Lazy Eye".
This refers to the condition in which vision (usually through only one
eye)
is poor due to lack of use (of that eye) in early childhood. Although
the affected eye generally looks normal, it may not be used normally
because the brain is favouring the other eye. If the other eye is working
well, as is often the case, amblyopia may not be detected
unless found during eye/vision tests such as those administered to all
children of a particular age-group at a certain early stage of their school
education. Such tests are not given to all children (worldwide) but when
used may detect amblyopia at a sufficiently early age
to enable effective treatment.
Causes of amblyopia, in general terms:
The "visual pathways" through which the sensation and understanding
of sight are passed between the eyes and brain are developed from birth
until the age of about 7-8 years. If during this time, a young child cannot
or does not use both eyes normally then normal vision through the affected
eye (or eyes) is not learnt, so may become permanently below average or
otherwise abnormal.
Although its effect is on the patient's visual perception, amblyopia
is really a developmental problem of the brain rather than a problem
within the eye itself. Many texts indicate that visual impairment
from amblyopia generally becomes permanent if not treated treated while
the visual pathways are still forming and developing - so ideally before
the age of about seven years.
Common Treatment for amblyopia:
Children diagnosed with amblyopia affecting one eye may
be advised to wear a patch over the other (unaffected) eye for several
weeks in order to stimulate and strengthen the neuro-chemical signals
from the eye with amblyopia to the brain. The purpose
of this is to encourage and build more normal nerve function along that
pathway to and within in the brain, to improve vision from that eye. As
well as patching the unaffected eye, one hour of “near” (close-up)
work, such as drawing, painting, or colouring, may also be recommended.
The patient is usually also asked to attend regular check-ups at which
both eyes are tested and requirements for spectacles assessed.
Regular consultations with an appropriate professional are important,
not least because there are some concerns that using an eye patch for
too long may affect the strong eye. As explained above, professional assistance
should be sought as soon as amblyopia is suspected.
More about Ophthalmology: This section includes short definitions
of many diseases, disorders, and conditions of the eyes and visual system.
For definitions of other terms in this category, choose from the list
to the left (but note that this is not a complete/exhaustive list).
Other related pages include the diagram
of the eye, and definitions
of parts of the eye, a description
of the human retina, and definitions
of parts of the retina, and the section of short definitions
of clinical and surgical procedures re. eyes and human visual system.
For further information see also our section of Books
about Ophthalmology. |
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This Section
is about
Diseases
and Disorders of the Eyes and Visual System.
To read about other diseases, disorders, or conditions of the eye and
human visual system, use the links on the left-side of this page.
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