Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

What is Amblyopia - Lazy eye?

The brain and the eye work together to produce vision. Light enters the eye and is changed into nerve signals that travel along the optic nerve to the brain. Amblyopia is the medical term used when the vision in one of the eyes is reduced because the eye and the brain are not working together properly. The eye itself looks normal, but it is not being used normally because the brain is favoring the other eye. This condition is also sometimes called lazy eye.
Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

How common is Amblyopia - Lazy eye?

Amblyopia is the most common cause of decreased vision in children. The condition affects approximately 2 or 3 out of every 100 children. It is estimated that as many as three percent of children in the U.S. have some degree of vision impairment due to amblyopia. Unless it is successfully treated in early childhood, amblyopia usually persists into adulthood, and is the most common cause of monocular (one eye) visual impairment among children and young and middle-aged adults.

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Causes of Amblyopia - Lazy eye

Amblyopia occurs when the nerve pathway from one eye to the brain does not develop during childhood. This occurs because the abnormal eye sends a blurred image or the wrong image to the brain.
  • This confuses the brain, and the brain may learn to ignore the image from the weaker eye.
  • Strabismus is the most common cause of amblyopia. There is often a family history of this condition.
  • The term "lazy eye" refers to amblyopia, which often occurs along with strabismus. However, amblyopia can occur without strabismus and people can have strabismus without amblyopia.
Other causes include:
Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye
  • Childhood cataracts
  • Farsightedness, nearsightedness, or astigmatism, especially if it is greater in one eye

Symptoms of Amblyopia - Lazy eye

Amblyopia develops early, usually before age 6, and symptoms may not always be obvious. The earlier it is diagnosed and treated, the better. For this reason, it is recommended that children receive a full eye exam at six months, and again at three years. Symptoms of Lazy Eye include:
  • Eyes that point in different directions
  • Significant favoring of one eye
  • Poor depth perception
  • Poor vision in one eye

How is amblyopia diagnosed?

Your child's pediatrician or the vision program at school will check three features of your child's eye health:

  • Do your child's eyes let light all the way through?
  • Do both eyes see equally well?
  • Are the eyes moving normally? Are they aligned normally?
If there seems to be a problem (something blocking the light, the vision is unequal, a problem with the movement of the eyes), the pediatrician or school nurse might recommend a visit to an eye specialist, also known as a pediatric ophthalmologist.

The eye doctor has special instruments that can see inside the eyes and measure how well each eye focuses. He or she can also perform special tests to make sure the eyes are moving together correctly.

Sometimes these problems will be found before the child develops ambly¬opia. In most children with amblyopia, however, the vision has already started to worsen by the time they visit the doctor.

Treatment for Amblyopia - Lazy eye

With early diagnosis and treatment, improved sight in a lazy eye can be accomplished. However, in the worst cases, an untreated eye can be left functionally blind.
Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

Children with a refractive error (nearsightedness, farsightedness, or astigmatism) will need glasses.
Next, a patch is placed on the normal eye. This forces the brain to recognize the image from the eye with amblyopia. Sometimes, drops are used to blur the vision of the normal eye instead of putting a patch on it.

Treatments for lazy eye include:

Patching or covering the strong eye: this method forces the weaker eye to work harder, naturally strengthening its ability to move and focus
Contact lenses and eyeglasses: corrects the discrepancy of near- or farsightedness between the eyes
Surgery: Realigns muscles in the eyes, a more expensive and risky option than other forms of treatment

For treatment of crossed eyes, see: Strabismus

Children whose vision will not fully recover, and those with only good eye due to any disorder should wear glasses with protective polycarbonate lenses. Polycarbonate glasses are shatter- and scratch-resistant.

How is amblyopia treated in children?

Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

Amblyopia treatment is most effective when done early in the childĘ s life, usually before age 7. Treating amblyopia involves making the child use the eye with the reduced vision (weaker eye). Currently, there are two ways used to do this:


A drop of a drug called atropine is placed in the stronger eye once a day to temporarily blur the vision so that the child will prefer to use the eye with amblyopia. Treatment with atropine also stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely.


An opaque, adhesive patch is worn over the stronger eye for weeks to months. This therapy forces the child to use the eye with amblyopia. Patching stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely. To be effective, patching must usually be done for a minimum of six hours each day.

What is the outlook for children with amblyopia?

If other eye problems are treated and the amblyopia is detected and treated early, most children will regain normal vision in the amblyopic eye. Amblyopia becomes much more difficult to treat in older children. If there is too much vision lost in the eye with amblyopia, it might be impossible to get it all back, but treatment should be continued until no more improvement is obtainable.

It is very important that you follow your doctor's advice about treatment. This can be difficult, because many children do not want to wear an eye patch every day. With the use of atropine as another method of treatment, more and more children with amblyopia can be successfully treated.

When should children have eye examinations?
Amblyopia often starts before there is any obvious sign that something is wrong. This is why babies and young children need to have their eyes checked at regularly scheduled appointments with the doctor.

The American Academy of Ophthalmology recommends that children have eye examinations at the following times:

  • before the child is 3 months old
  • between the ages of 6 months and 1 year
  • at 3 years of age
  • at 5 years of age

If there are concerns that your child may be suffering from or developing “lazy eye,” have your child evaluated right away. In families with a history of amblyopia, there is also an increased risk to these new family members.

Can amblyopia be treated in adults?

Causes, Symptoms, Diagnosis and Treatment for Amblyopia - Lazy eye

During the first six to nine years of life, the visual system develops very rapidly. Complicated connections between the eye and the brain are created. We do not yet have the technology to create these eye-to-brain connections in older children and adults.

Scientists are exploring whether treatment for amblyopia in older children and adults can improve vision.