Prevalence of 2 percent, the most common cause of uncorrectable loss of vision in children.
Dysfunction of the processing of visual information.
Commonly known as lazy eye.
Evident as reduced recognition visual acuity.
Process not correctable with glasses or contact lenses.
No intrinsic eye disease.
The brain does not fully acknowledge the images seen by the eye affected by amblyopia.
Clinical ocular examination is usually normal but microscopic abnormalities have been found in the retina, lateral geniculate bodies and visual cortex.
Results from degradation of retinal image during visual development thought to be during the first 7 years of life.
The degradation of the image and central suppression that leads to amblyopia results from strabismus, anisometropia or deprivation.
Estimated prevalence 1.5% in children.
Most common cause of monocular vision loss in children.
Almost always affects one eye but may cause reduction in vision of both eyes.
When the brain favors one eye, the weaker eye wanders inward and outward and eventually the brain ignores the signals received from the weaker eye.
Can be caused by deprivation of vision in early life, strabismus, by vision obstructive disorders, by degrees of myopia or hyperopia in each eye (anisometropia).
Strabismus refers to misalignment of the eyes resulting in normal vision in the preferred sighted eye and causes abnormal vision in the deviated eye from the discrepancy between the images projected t the brain from the two eyes.
Because of non recognition or treatment failure causes loss if vision in an estimated 2.9% of adults.
In adults it usually causes double vision, since the eyes are not fixated on the same object, while children can suppress images from one of the eyes eliminating diplopia.
Conservative treatment with corrective glasses or eye patches can correct the process.
Treatment provides clarification of the visual image with glasses and using the amblyopic eye with an eye patch over the dominant eye or providing atropine to paralyze the muscles and weaken the vision of the good eye.
Surgery may be needed for treatment.
Left untreated may lead to permanent impairment of vision.
Refractive amblyopia may be a result of anisometropia, referring to unequal refractive errors between the two eyes.
In refractive amblyopia the far sighted eye provides the brain with the clearer image, and is favored by the brain.
Refractive amblyopia is usually a less severe process than strabismus amblyopia.
May be associated with a combination of strabismus and anisometropia.
Pure refractive process treated by correcting refractive error with lenses.
Pure refractive amblyopia treated with eye patching and vision therapy.
Form-deprivation type amblyopia occurs when the ocular media become opaque as with cataracts, or corneal scarring from forceps injuries from birth.
Opacities prevent adequate sensory input from reaching the eye and prevent visual development.
Treatment of opacity, if not timely, amblyopia may persist even after the cause of the opacity is removed.
Pediatric Eye Disease Group found that the use of atropine or patching of the sound eye resulted in similar degrees of improvement among 7-13 years olds with moderate disease.