What Causes Lazy Eye (Amblyopia)?

By Marisa Ramiccio. May 7th 2016

When some people hear the term “lazy eye,” they think of someone who is cross-eyed. They may think that it’s a physical condition, but the truth is a lazy eye is actually a medical condition in which a person loses the ability to see details. In most cases, the loss of vision can be restored through simple treatments.

What Causes Lazy Eye?

In medical terms, a lazy eye is better known as amblyopia. But through the years, people have come to know this condition by the laymen’s term because it describes the visible symptom of the eye turning inward or outward. But there are invisible symptoms of this condition, as well:

  • Inability to correctly judge depth
  • Poor vision in one eye, although both eyes may be affected

Amblyopia is a condition that commonly affects children and is a leading cause of children’s vision problems. Children who have a history of amblyopia in their family, were born prematurely or who have developmental delays as they age are more likely to develop amblyopia.

[See: 7 Common Eye Problems In Children]

The reason children are mostly affected is because amblyopia occurs during development, when the nerve pathway between the brain and the eye fails to develop. When this happens, the eye sends a blurred or distorted picture to the brain, and over time, the brain begins to ignore the images sent from the eye, hence the loss of vision. But amblyopia doesn’t just develop on its own. It’s typically caused by one of the following conditions:

  • Strabismus – An imbalance in the positioning of the eyes. This is what causes the eye to turn either inward or outward and prevents the eyes from working in tandem.
  • Abnormalities – In some cases amblyopia is caused by an abnormality like childhood cataracts, an abnormal central retina, an abnormal eye shape or a difference in eye size.
  • Refractive errors – Amblyopia may also be caused by refractive errors such as astigmatism, nearsightedness and farsightedness.
  • Tumors – Sometimes a tumor may turn out to be the cause of a lazy eye.

How Serious Is Lazy Eye?

Amblyopia is a serious condition, but in most cases children can recover from it. However, a person’s recovery from lazy is largely dependent on age. Children under the age of 5 can be expected to make a full recovery while children over the age of 10 usually make a partial recovery; the earlier amblyopia is detected and treated, the greater the chance for a full recovery. If treatment is delayed, this can lead to the condition becoming partially or fully permanent.

But that doesn’t mean that hope is completely lost for older children and adults who have long-standing amblyopia. The FDA has approved a computer program called RevitalVision, which works as a therapy treatment for those with this condition. The program helps children and adults work on their visual acuity and contrast sensitivity. A study conducted on RevitalVision users showed that more than 70 percent of children and adults who used this program were able to improve their visual acuity after completing the full training session, which consisted of forty 40-minute sessions.

Treating Lazy Eye

For those who are in the beginning stages of amblyopia, the treatment will depend on how severe the condition is and how far along it has progressed. If the amblyopia is caused by a refractive error, corrective eyeglasses are likely to be the only treatment needed. But if the amblyopia is a little farther along or is caused by something else, one of these treatments may be prescribed:

  • Eye patch – If the amblyopia is caused by strabismus, the child may need to wear an eye patch over the stronger eye to strengthen the weaker eye.
  • Eye drops – If the eye patch is too annoying or uncomfortable for the child, eye drops may be prescribed as an alternative. The eye drops contain atropine, which will temporarily blur the vision in the stronger eye, leaving the brain to depend on, and strengthen, the weaker eye. However, atropine eye drops can cause serious side effects such as light sensitivity and the possible paralysis of the ciliary muscle.
  • Prosthetic contact – Another alternative to these treatments is the prosthetic cataract, which blocks light from the stronger eye. This will also allow the weaker eye to strengthen. The contact will be specially designed for the child and will not affect his or her appearance.
  • Surgery – In some cases, particularly with strabismus or cataracts, surgery may be required to correct the positioning of the eye.

After treatment has begun, children can expect to notice a difference in their sight after a few months, or even a few weeks, depending on the treatment and severity of the amblyopia. The best treatment, though, is early detection. Through regular eye exams and check-ups, amblyopia can easily be identified in young children. Once the problem has been identified, recovery through proper treatment can begin.


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