Those who have no organic disease in the eye and whose corrected visual acuity is less than 0.9 are called amblyopia. Amblyopia is a common childhood eye disease in ophthalmology. It is a state in which visual function declines due to various reasons such as perception, movement, conduction, and visual center due to various reasons such as perception, movement, conduction, and visual center. , Mainly manifested as low vision and binocular monocular dysfunction.
How does amblyopia in children cause
1, strabismus amblyopia
occurs in a single eye, children have strabismus or have had strabismus, it is common in patients with monocular constant strabismus who are under four years of age, because the cerebral cortex actively inhibits the visual impulse of squint , Long-term inhibition of the formation of amblyopia. Visual suppression and amblyopia are only the difference in amount. Generally, the suppression can be relieved when the squint is injected, while amblyopia is a persistent vision loss. The earlier the strabismus occurs, the faster the suppression and the deeper the degree of amblyopia.
2, anisometropic amblyopia,
, because of the different vision in the two eyes, the sharpness of the retinal imaging size of the two eyes is different, and the macular image of the higher diopter eye is large and blurred, causing insufficient fusion reflex stimulation of the two eyes and unable to form binocular monocular vision. Passive inhibition occurs, and those with a refractive index of 3.00D or more in both eyes have higher refractive power and often form amblyopia and strabismus. The depth of amblyopia is not necessarily related to the degree of anisometropia, but it is related to the nature of the fixation. The amblyopia of the central watchers is deeper. The nature of this type of amblyopia is similar to that of strabismic amblyopia, and it is functional and reversible. It is sometimes difficult to distinguish clinically whether amblyopia is primarily caused by anisometropia or secondary to strabismus. If this type can be detected early and wear glasses in time, it can be prevented.
3, refractive amblyopia
is mostly binocular, occurs in children or adults with high myopia, myopia and astigmatism without corrective glasses. Most myopia is above 6.00D, hyperopia is above 5.00D, astigmatism ≥2.00D or Those with astigmatism. The visual acuity of both eyes is equal or similar, and there is no dysfunction of the fusion of objects and images of the eyes, so it does not cause macular functional inhibition. If you wear appropriate glasses in time, your visual acuity can gradually improve.
4. Disuse amblyopia (form deprivation amblyopia)
In infancy, due to ptosis, corneal opacity, congenital cataract, or because of too long cover time after eyelid surgery, the light stimulation cannot enter the eyeball, hindering or Blocking the macula to receive form stimuli, resulting in amblyopia, it is also called blocked visual stimulus amblyopia.
5, congenital amblyopia or organic amblyopia
due to macular hemorrhage at birth, resulting in irregular arrangement of cone cells, which occurs before the formation of the eyes after the baby is born, so the prognosis is not good. Although some obvious lesions of the retina and central nervous system cannot be detected, they are still considered to be organic lesions. Because the existing examination methods cannot be found, this type is constant amblyopia, and the treatment is ineffective.
What are the symptoms of amblyopia in children?
1, vision is lower than normal, not only the naked eye vision is low, but the corrected vision is also lower than normal and meets the diagnostic criteria for amblyopia.
2, vision "crowding", that is, the ability of amblyopic eyes to recognize a single letter of vision is significantly higher than that of a line of letters. For example, the same 0.3-line E letter, if only a single letter is shown to the child, the amblyopic eye can easily recognize it, but once the E letter is displayed in a row, it is difficult for the amblyopic eye to distinguish the direction of the opening.
3, the contrast sensitivity of amblyopic eyes is reduced.
4. There are electrophysiological changes in amblyopic eyes, the latency of the visual evoked potential P100 wave is prolonged, and the amplitude is reduced.
5. Abnormal gaze properties: when a normal person looks at the target, the object image falls on the fovea of the macular fovea in both eyes to form a clear vision. Among patients with amblyopia, some patients do not take foveal gaze, and parafoveal gaze, macular gaze, and peripheral gaze can be found with projection lens inspection. The more the fixation point deviates from the fovea, the lower the vision and the more difficult the treatment.
6. Abnormal binocular vision: Amblyopia not only causes low vision, but also endangers the normal development of binocular vision, resulting in tertiary visual function defects. After checking the visual function with the synoptograph, it was found that the child had no level III stereo vision function, the range of level II fusion function was small or unable to fusion, and even did not have level I simultaneous vision function. Binocular vision is a high-level vision function possessed by humans, ensuring that the two eyes cooperate with each other and play their due role in work and life. Damage or loss of this function will affect the quality of people's study, life and work.
