الفهرس 
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Abstract
The term amblyopia is derived from the Greek language and means dull vision: amblys _ dull, ops _ eye, i.e. dull eye. It is the most common cause for decreased vision in children with 1-5%. 1-3
Amblyopia is the unilateral, or rarely bilateral, decrease in the best corrected visual acuity caused by vision deprivation and/or abnormal binocular interaction, for which there is no identifiable pathology of the eye or visual pathway. 4
Amblyopia may be classified as strabismic, refractive (anisometropic and isometropic), deprivational, idiopathic, and mixed types. This disruption must occur during the critical period of visual development (the first 8-10 years of life). If the same disorders occur later in life, amblyopia does not develop. 5
Strabismic amblyopia results from abnormal binocular interaction where there is continued monocular suppression of the deviating eye. 4
Anisometropia has been defined as a condition in which there is a difference of 0.5–2 dioptres in refractive error between the two eyes. 6
In anisometropic amblyopia, focused and unfocused images coming out of the point of fixation produce a blurred image in the fovea of the eye and an abnormal binocular interaction develops to the disadvantage of the eye with blurred vision as a result of overlapping clear and blurred images, leading to inhibition of the fovea and poor vision in that eye. 7
Bilateral ametropic amblyopia results from high symmetrical refractive errors, usually herpermetropia. Meridional amblyopia results from image blur in one meridian (e.g. uncorrected astigmatism).Stimulus deprivation amblyopia results from vision deprivation. It may be unilateral or bilateral and it is typically caused by media opacity (e.g. cataract) and ptosis where lid is covering the pupil.In absence of organic lesion.
A difference in best corrected visual acuity of two snellen lines or more (or < 1 log unit) is indicative of amblyopia. 4
Treatment of amblyopia includes correcting refractive errors with glasses or contact lenses, patching or penalization of the fellow eye which depends on various factors such as the severity of amblyopia, amount and type of refractive error, eye alignment status and age at initiation of treatment and the degree of compliance. Despite appropriate treatment for amblyopia, about 50% of children cannot achieve complete vision of 20/20. It is possible that there is subclinical pathology in the retina, especially in the macula of eyes not responding well to conventional amblyopia treatment. 8
Optical coherence tomography (OCT) was first described in 1991 and first used in ophthalmology practice in 1995. It allows to perform an optical biopsy of tissues by taking advantage of the differential optical refraction properties of different tissues and to examine 10 μm thick sections. It is a noncontact, noninvasive, easily reproducible method that uses only light. 9
Optical coherence tomography (OCT) uses a continuously emitting optically coherent laser diode centered at 850 nm and focused at the retina. The super-luminance low-coherence diode emits light with a 20 to 25 nm band width. For thickness measurements, the time delay of reflected or backscattered light is determined using coherence interferometry. The anterior and posterior margins of the retina are defined by highly reflected layers (the nerve fiber layer (NFL) and retinal pigment epithelium/chorio-capillaries). In the area of the fovea, the retinal pigment epithelium/chorio-capillaries appears distinct from the external segments of the photoreceptors. The stratified structure of the retina is composed of alternating layers of moderate and low reflectivity, and the photoreceptors appear minimally reflective. Moderate backscattering is observed from the inner and outer plexiform layers, which like the NFL; consist of fibrous structures running perpendicular to the incident light 9
Evidences for direct retinal changes in amblyopic eyes are still inconclusive and controversial, although electroretinograms elicited by patterned stimuli in humans with various types of amblyopia were found to be significantly reduced. Studies using optical coherence tomography (OCT) imaging of the retina have not produced definite results. 10.