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 or the
posterior visual pathway. Defect of central
vision.
Amblyopia
The most common form of amblyopia
Strabismic Amblyopia
Result from competitive or inhibitory interaction between neurons carrying the nonfusible inputs from the two eyes.
Strabismic Amblyopia
Second in frequency
Anisometropic Amblyopia
It develops when unequal refractive error in the two eyes causes the image on the one retina to be chronically defocused.
Anisometropic Amblyopia
(1-2D) 🡺 mild amblyopia
Mild hyperopic or astigmatic anisometropia
(less than -3D) usually doesn’t cause amblyopia
Mild myopia anisometropia
(-6D) 🡺 severe amblyopia visual loss.
Unilateral high myopia
Result from large, approximately equal, uncorrected refractive error in both eyes of a young child.
Isometropic amblyopia
Hyperopia exceeding 5D & myopia excess of
10 D 🡺 risk🡺____________.
Bilateral amblyopia
Uncorrected bilateral astigmatism in early childhood may result in loss of resolving ability limited to chronically blurred meridians.
Meridional amblyopia
It is usually caused by congenital or early acquired media opacity.
Stimulus Deprivation Amblyopia
In bilateral cases acuity can be _______ or worse.
20/200
This form of amblyopia is the least common but most damaging and difficult to treat.
Stimulus Deprivation Amblyopia
May cause mild to moderate amblyopia or may have
no effect on visual development.
Small polar cataracts & lamellar cataracts
A form of deprivation caused by excessive therapeutic patching.
Occlusion amblyopia
A test for estimating the relative level of vision in the two eyes for children with strabismus who are under the age of about 3.
Binocular fixation pattern
Quite sensitive for detecting amblyopia but results can be falsely positive.
Binocular fixation pattern
The modified Snellen technique directly measures acuity in children 3-6 years old.
Binocular fixation pattern
Allow the examiner to test the crowding phenomenon with isolated optotype. Bar surrounding the optotype mimic the full optotype to the amblyopic child.
Crowding bar, or contour interaction bars
Defined as occlusion for all or all but one waking
hour.
Full time occlusion of the sound eye
It is the most powerful means of treating of amblyopia by enforced use of the defective eye.
Full time occlusion of the sound eye
Defined as occlusion for 1-6 hours per day.
Part-time occlusion
This form of treatment has recently been demonstrated to be as effective as patching for mild to moderate amblyopia.
Penalization
