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
- A diagram of the eye
- Definitions and descriptions of the parts of the eye
- A concise description of the human retina
- Definitions of parts of the retina
- Clinical and surgical procedures re. eyes and human visual system
For further information see also our pages of books about ophthalmology.