Amblyopia or lazy eye syndrome

Medical content revised by - Last revision 31/08/2020
Amblyopia or lazy eye syndrome


  • Amblyopia or lazy eye syndrome is caused by an insufficient development in visual ability in one eye during the first years of life.
  • It might be caused by a strabismus, a high difference in refraction power between both eyes or by any cause that prevents the visual stimulus from properly reaching the child’s retina (for example, a media opacity).
  • As one of both eyes has good vision, if often goes unnoticed. In case it is secondary to a strabismus, parents may observe an eye deviation. And if it is secondary to an eyelid ptosis (drooping upper eyelid) or to a congenital cataract (lack of transparency in crystalline lens), it may be early detected when observing an eyelid asymmetry or the absence of red reflex or “white spot” in one of the eyes.
  • Treatment for lazy eye are eye occlusions. Moreover, contingent upon the mechanism that has caused amblyopia, it may require additional treatments (prescription of optical correction means or surgery).

Amblyopia or lazy eye syndrome

Failure in vision development in one eye during the first years of a child’s life.

It may be caused by:


Difference in refraction power between both eyes (anisometropia)

Failure of the visual stimulus in reaching the retina, or deprivation amblyopia (due to a cataract or a ptosis…)

It needs to be treated before the age of 8, as beyond that age vision defects may remain incorrigible.

What is amblyopia or lazy eye syndrome?

Amblyopia or lazy eye syndrome is an alteration in vision (one eye sees worse than the other) caused by lack of symmetry in the use of the eyes during the first eight years of life (vision development period). In a nutshell, the child sees better with one eye when comparing with the other.

Even if there is no other disease hindering visual ability in any of the eyes, the brain receives worse quality visual information from one of the eyes and ends up ignoring it. Over time, that eye becomes lazy.

Why does it occur?

Amblyopia occurs when the brain ignores visual information coming from one eye as it features a worse quality than the other, even though its structures are healthy.

This may be due to:

  • An alteration in eye alignment or strabismus.
  • Anisometropia: difference in refraction power between one eye and the other. The child uses more the eye that lets him focus more easily stops using the eye with higher refraction error. Family and people around the child do not perceive anything out of normal, as the child has normal vision with one of his eyes.
  • Deprivation amblyopia: cataract (lack of transparency in crystalline lens), a ptosis (drooping upper eyelid), or a corneal opacity may hinder vision development.

How is lazy eye detected? What are its symptoms

Amblyopia or lazy eye syndrome are not always easy to detect, as depending on its cause, it may not be seen at first sight.

Moreover, if there is a visual deficit only in one eye, it is highly difficult to detect it at home. In addition to this, children are, in most cases, not aware of their visual deficit.

In amblyopia, the most important thing are early detection and treatment. Parents who have suffered from amblyopia themselves must pay special attention to their children. It is recommended that they have their eyes examined around the 3 years of age.

There are, however, some warning signs that should call our attention and make us bring our children to the ophthalmologist, as they can be paired with specific children eye diseases, such as:

  • Squinting or closing often the eyes when trying to look at something
  • Tilting the head continuously in the same position (stiff neck) when focusing on something.
  • Rubbing the eyes frequently and having itchy eyes.
  • Having continuous headaches, especially during the evening.
  • Getting too close to paper sheets in order to read or draw.
  • Experiencing tearing o redness
  • Feeling discomfort to sun or problems adapting to darkness (falling in dim light conditions)
  • Eye deviation

How can it be treated?

Amblyopia treatment consists in:

  • Correcting refraction errors (myopia or hyperopia) by means of glasses.
  • Eliminating the obstacle hindering a proper simultaneous stimulation of both retinas (cataract or drooping eyelid surgery, improving corneal clearness, etc.).
  • Studying and correcting the strabismus that hinders binocular vision.
  • Occlusions with eye patches in order to exercise the lazy eye while the child perform tasks, preferably in near vision (drawing, painting, reading, etc.).

The most important thing when it comes to amblyopia is early diagnose and treatment. Visual prognosis of the child will depend on it.

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