Amblyopia (Lazy Eye)

Amblyopia, commonly called “lazy eye,” is a vision condition that develops in childhood in which the brain and one eye fail to work together properly, causing reduced vision that worsens over time if left untreated.

Overview

Amblyopia is a type of poor vision that usually happens in just one eye but less commonly in both eyes. It develops when there is a breakdown in how the brain and the eye work together, and the brain cannot recognize the sight from one eye. Over time, the brain relies more on the other, stronger eye while vision in the weaker eye gets worse.

It is called “lazy eye” because the stronger eye works better. People with amblyopia are not lazy, and they cannot control the way their eyes work.

Amblyopia starts in childhood, and it is the most common cause of vision loss in kids. Early treatment works well and usually prevents long-term vision problems.

Signs and Symptoms

Some children are born with amblyopia and others develop it later in childhood. Symptoms of amblyopia can be hard to notice. Children with amblyopia may have poor depth perception, meaning they have trouble seeing how near or far something is located. Parents may also notice signs that their child is struggling to see clearly, including:

  • Squinting
  • Shutting one eye
  • Tilting their head

In many cases, parents do not know their child has amblyopia until a doctor diagnoses it during an eye exam.

Causes and Risk Factors

Normally, the brain uses nerve signals from both eyes to see. If an eye condition makes vision in one eye worse, the brain may try to work around it, and it may start to “turn off” signals from the weaker eye and rely only on the stronger eye.

Eye conditions that can lead to amblyopia include:

  • Refractive errors: These include common vision problems like nearsightedness (having trouble seeing far away), farsightedness (having trouble seeing things up close), and astigmatism (which can cause blurry vision). If they are not corrected, the brain may start to rely more on the eye with stronger vision.
  • Strabismus: Usually, the eyes move together as a pair. In children with strabismus, the eyes do not line up and one eye might drift in or out.
  • Cataract: This causes cloudiness in the lens of the eye, making things look blurry. While most cataracts happen in older people, babies and children also can develop cataracts.

The chances of having amblyopia are higher in children who:

  • Were born early (premature) and had retinopathy of prematurity
  • Were smaller than average at birth
  • Have a family history of amblyopia, childhood cataracts, coloboma (a condition where part of the tissue that makes up the eye is missing), or other eye conditions
  • Have developmental disabilities

Treatment and Management

If there is a vision problem causing amblyopia, the doctor may treat that first. For example, doctors may recommend glasses or contacts for children who are nearsighted or farsighted, or surgery for children with cataracts.

The next step is to retrain the brain and force it to use the weaker eye. The more the brain uses it, the stronger it gets. Treatments include:

  • Wearing an eye patch on the stronger eye: By covering up this eye with a stick-on eye patch (similar to a bandage), the brain has to use the weaker eye to see. Some children only need to wear the patch for two hours a day, while others may need to wear it whenever they are awake.
  • Putting special eye drops in the stronger eye: A once-a-day drop of the drug atropine can temporarily blur near vision, which forces the brain to use the other eye. For some children, this treatment works as well as an eye patch, and some parents find it easier to use. For example, because young children may try to pull off eye patches.

After a child starts treatment, their vision may start to get better within a few weeks. It will probably take months to get the best results. After that, a child may still need to use these treatments from time to time to stop amblyopia from coming back.

It is important to start treating children with amblyopia early. Children who grow up without treatment may have lifelong vision problems.

Living With Amblyopia

Parents and caregivers play an important role in helping children with amblyopia follow their treatment plan. Because young children may try to pull off eye patches, some families find that atropine eye drops are easier to manage.

Patients are encouraged to actively participate in their own healthcare. Working together with an eye care professional can improve eye health and overall quality of life. It helps to ask questions, take notes, and ask for written instructions during appointments.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on amblyopia.

Find Treatment

If you are concerned about your child’s vision, contact an eye care professional. Resources include:

Research

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.  

NIH supports research on the causes, prevention, diagnosis, and treatment of eye disorders and conditions.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.