Amblyopia

Amblyopia is a visual impairment resulting from abnormal visual stimulation during early childhood, the prevalence of which ranges from 1% to 4%.

Can result from strabismus, form deprivation (e.g., due to congenital cataracts or corneal opacities), and various types of refractive error. These errors include anisometropia (unequal refractive error between the two eyes), isoametropia (high but similar refractive error in the two eyes), and high astigmatism in one or both eyes.

Amblyopia due to strabismus with or without refractive error is commonly treated with initial optical correction, and subsequent patching or atropine penalisation of the better-seeing eye. Amblyopia due to refractive error alone frequently responds to optical correction alone.

Amblyopia due to form deprivation is treated initially with early surgery, to remove the visual obstruction. In unilateral or asymmetric cases, patching of the better-seeing eye is necessary after surgery.

Treatment is highly successful when instituted during infancy and pre-school years, although some children as old as 13-17 years respond to treatment, particularly if there has been no prior therapy.

Amblyopia is a reduction of best corrected visual acuity (usually unilateral, but may be bilateral) that is not attributable solely to a structural abnormality of the eye or visual pathways.[1]Cruz OA, Repka MX, Hercinovic A, et al. Amblyopia preferred practice pattern. Ophthalmology. 2023 Mar;130(3):P136-78. https://www.aaojournal.org/article/S0161-6420(22)00865-X/fulltext http://www.ncbi.nlm.nih.gov/pubmed/36526450?tool=bestpractice.com ​​ For the brain to learn to see with each eye, and to develop the capacity for binocular vision, each eye must have a clear and focused retinal image, and the two eyes must be aligned. Research has demonstrated that there are critical periods for the development of normal vision, and that amblyopia is associated with structural changes in the primary visual cortex.[2]Wiesel TN, Hubel DH. Single-cell responses in striate cortex of kittens deprived of vision in one eye. J Neurophysiol. 1963 Nov;26:1003-17. https://jn.physiology.org/cgi/reprint/26/6/1003 http://www.ncbi.nlm.nih.gov/pubmed/14084161?tool=bestpractice.com [3]Hubel DH, Wiesel TN. The period of susceptibility to the physiological effects of unilateral eye closure in kittens. J Physiol. 1970 Feb;206(2):419-36. https://onlinelibrary.wiley.com/doi/10.1113/jphysiol.1970.sp009022/abstract http://www.ncbi.nlm.nih.gov/pubmed/5498493?tool=bestpractice.com