Amblyopia Flashcards
Unilateral, or less commonly bilateral, reduction of best corrected visual acuity that can not be attributed directly to the effect of any structural abnormality of the eye of the posterior visual pathway
Amblyopia
Defect of central vision
Amblyopia
Amblyopia is the result of:
Strabismus, anisometropia, high bilateral refractive error (isoametropia), stimulus deprivation
Prevalence in North American population
2% to 4%
Amblyopia is commonly unilateral or bilateral?
Commonly unilateral
The most common form of amblyopia; thought to result from competitive or inhibitory interaction between neurons carrying the nonfusible inputs from the two eyes, which results to domination of cortical vision
Strabismic Amblyopia
Second in frequency; it develops when unequal refractive error in the two eyes causes the image on the one retina to be chronically defocused.
Anisometric Amblyopia
This is subdivided into isometric amblyopia and meridional amblopia
Amblyopia due to bilateral high refractive error (isometropia)
results from large, approximately equal, uncorrected refractive error in both eyes of a young child; hyperopia exceeding 5D and myopia excess of 10D is at risk of this bilateral amblyopia
Isometropic amblyopia
uncorrected bilateral astigmatism in early childhood may result in less resolving ability limited to chronically blurred meridians
Meridional amblyopia
it is usually caused by congenital or early acquired media opacity
this form of amblyopia is the least common but most damaging and difficult to treat
in bilateral cases acuity can be 20/200 or worse
Stimulus Deprivation Amblyopia
a test for estimating the relative level of vision in the two eyes for children with strabismus who are under 3 years old.
quite sensitive for detecting amblyopia but results can be falsely positive
Binocular function pattern
