This condition has been associated with amblyopia ( in 54 % of cases ), anisometropia ( 26 % ), and strabismus ( 56 % ).
12.
Several studies have found that anisometropia occurs more frequently and tends to be more severe for persons with high ametropia, and that this is particularly true for myopes.
13.
Aniseikonia can occur naturally or be induced by the correction of a refractive error, usually anisometropia ( having significantly different refractive errors between each eye ) or antimetropia ( being glasses and contacts.
14.
In certain types of anisometropia, the visual cortex of the brain will not use both eyes together ( binocular vision ), and will instead suppress the central vision of one of the eyes.
15.
More specifically, for patients with esotropia who undergo strabismus surgery, anisometropia may be one of the risk factors for developing consecutive exotropia and poor binocular function may be a risk factor for anisometropia to develop or increase.
16.
More specifically, for patients with esotropia who undergo strabismus surgery, anisometropia may be one of the risk factors for developing consecutive exotropia and poor binocular function may be a risk factor for anisometropia to develop or increase.
17.
In case of strong anisometropia, contact lenses may be preferable to spectacles because they avoid the problem of visual disparities due to size differences ( aniseikonia ) which is otherwise caused by spectacles in which the refractive power is very different for the two eyes.
18.
Anisometropia follows a U-shape distribution according to age : it is frequent in infants aged only a few weeks, is more rare in young children, comparatively more frequent in teen-agers and young adults, and more prevalent after presbyopia sets in, progressively increasing into old age.
19.
A definition that incorporates all of these defines amblyopia as a unilateral condition in which vision in worse than 20 / 20 in the absence of any obvious structural or pathologic anomalies, but with one or more of the following conditions occurring before the age of six : amblyogenic anisometropia, constant unilateral esotropia or exotropia, amblyogenic bilateral isometropia, amblyogenic unilateral or bilateral astigmatism, image degradation.
20.
Any visual deprivation, that is, anything interfering with such input over a prolonged period of time, such as a cataract, severe eye turn or strabismus, anisometropia ( unequal refractive error between the two eyes ), or covering or patching the eye during medical treatment, will usually result in a severe and permanent decrease in visual acuity and pattern recognition in the affected eye if not treated early in life, a condition known as amblyopia.
