【Causes・Disease】

Lazy eye (amblyopia) is reduced vision in one eye caused by abnormal visual development early in life. The weaker — or lazy — eye often wanders inward or outward. Amblyopia generally develops from birth up to age 7 years. It is the leading cause of decreased vision among children.
Amblyopia has four main causes.

1. ① Light is difficult to pass through the retina (Deprivation)
   If the Infant has a disease from birth, such as drooping eyelids or cloudy cornea, since the stimulation to enter the retina is not enough, the vision will not develop. For example, congenital cataracts. To receive visual stimuli properly, surgery or treatment may be required.
2. ② Position of one eye is deviated（Strabismus amblyopia）
   Strabismus is a state in which both eyes or eyesight are not facing in the same direction. Strabismus amblyopia is caused by strabismus or abnormal movement of the eyeball. If the eyesight of one eye is deviated, vision of that eye will not develop because that eye is not used.
3. ③ Incorrect focus on the retina (Refractive Amblyopia)
   If hyperopia and astigmatism is strong in both eyes, the light cannot focus properly on the retina. If hyperopia and astigmatism are strong, the vision will be blurry, therefore, the vision will not develop. Even if the refractive power of one eye is normal, the vision of another eye with abnormal refractive power such as hyperopia or astigmatism will not develop.
4. ④ The large refractive difference between the right eye and the left eye (asymptomatic amblyopia)
   If the refractive index of the right eye and the left eye is large, the eye with higher refractive index will not focus properly, and the eye will not be used, so the vision will not develop.

【Symptoms】

Patients with amblyopia are in a state in which vision is poor, so when they look at things, they often tilt their heads, shut one eye, or squint one eye. This happens because one eye with good vision tries to see while the other eye is in poor vision.

【Treatment】

Treatment of amblyopia varies depending on the type of amblyopia and when it occurs. In case of refractive abnormalities, patients can wear glasses to make the light focus on the central fossa of the retina to make a clear image to promote the development of vision.
If glasses can not improve vision, shielding training is necessary. During the shielding training, the eye with good vision will be covered by a shielding tape to encourage the eye with bad vision.

【Summary】

Amblyopia is important to be detected and to start proper treatment. Hyperopia and astigmatism can not be diagnosed by appearance. Even if there is no problem with the vision, be sure to get a 3-year-old check-up or school check-up properly, if necessary, please go to see an ophthalmologist.