Amblyopia is caused by abnormal visual experience such as monocular strabismus, anisometropia, ametropia and form deprivation during visual development. The best corrected visual acuity of monocular or binocular is lower than normal, and there is no organic disease in eye examination.

Amblyopia is mainly diagnosed by exclusion. Firstly, all pathological factors that may lead to vision loss and poor vision correction are excluded. At the same time, the diagnosis is made according to the possible causes of amblyopia, such as form deprivation, strabismus, ametropia and other factors. The later amblyopia is found and the less timely treatment is, the worse the prognosis is. Amblyopia usually occurs before the age of 6, usually monocular, but also binocular. Binocular disease is generally mild and easy to treat.

With the in-depth research on the prevention and treatment of amblyopia, different understandings are put forward.

1. Amblyopia is a disease related to both eyes. It is the result of the imbalance of competitive binocular visual stimulation input in the early stage of visual development. The dominant eye becomes the dominant eye and the inferior eye becomes the amblyopia eye. Therefore, the diagnosis of amblyopia is not based solely on the visual impairment, but on the difference of corrected visual acuity of both eyes. Those with two or more lines of corrected visual acuity are diagnosed as amblyopia.

2. Amblyopia itself is not completely without organic changes. In ametropic amblyopia, ametropia itself will lead to too long or too short eye axis, changes in corneal curvature, refractive index and morphology of lens, etc; In form deprivation amblyopia, the cause of form deprivation itself is the existence of organic lesions.

3. Amblyopia is not only the performance of low central vision, but also the obstacle of binocular visual function, that is, the obstacle of binocular simultaneous vision, binocular fusion image and binocular stereopsis.

4. The visual growth and development of infants and young children has a certain process, so the developing vision can not be regarded as amblyopia.

The definition of amblyopia is not completely consistent. It can be considered that amblyopia is disturbed and inhibited by some factors in the development of visual system, resulting in insufficient effective stimulation of visual cells, impairment and deprivation of visual function development.