Amblyopia or Lazy Eye
Lazy Eye (Amblyopia)
What is Lazy Eye?
Lazy eye, medically known as amblyopia, is a condition where one or both eyes do not develop normal vision during childhood.
A child with amblyopia may have an eye that appears completely normal, but the vision from that eye is weaker than it should be. This happens because the visual connection between the eye and the brain has not developed normally.
Importantly, lazy eye is not simply a problem with needing glasses. A child may have a clear spectacle prescription but still have reduced vision because the brain has not learned to use the image from one eye properly.
Amblyopia is one of the most common causes of reduced vision in children and is much easier to treat when detected early.
What Causes Lazy Eye?
Lazy eye can develop when the brain receives a consistently blurred, unequal or misaligned image from one or both eyes during the early years of visual development.
Common causes include:
1. Different spectacle prescriptions between the two eyes
If one eye is much more short-sighted, long-sighted or astigmatic than the other, the brain may favour the clearer eye and gradually ignore the image from the weaker eye.
This is called anisometropic amblyopia.
2. Squint or eye misalignment
If the two eyes are not pointing in the same direction, the brain may suppress the image from one eye to avoid seeing double.
This can lead to amblyopia.
3. Significant long-sightedness or astigmatism
A child does not necessarily need to have very different prescriptions between the two eyes to develop amblyopia. Significant uncorrected refractive errors in both eyes can also interfere with normal visual development.
4. An obstruction to vision
Less commonly, something physically blocks a clear image from reaching the retina.
Examples include a childhood cataract, drooping eyelid or other eye abnormality.
This type of amblyopia needs prompt assessment and treatment.
What Does a Child With Lazy Eye See?
A child with amblyopia may not realise that one eye is weaker.
This is because children generally assume that the way they see is normal.
A child may therefore have no obvious complaints even when the vision in one eye is significantly reduced.
This is one reason why children's eye screening is important.
A child can have good vision in one eye and poor vision in the other without parents or teachers noticing.
What Are the Signs of Lazy Eye?
Some children have no obvious symptoms.
Possible signs include:
One eye turning in, out, up or down
Frequently closing or covering one eye
Tilting or turning the head when looking at something
Difficulty judging distances
Poor hand-eye coordination
Difficulty with reading or visual tasks
One eye having significantly poorer vision than the other
Complaints of blurred or double vision
However, many children with amblyopia simply do not complain.
A proper eye examination is therefore more reliable than waiting for your child to tell you that something is wrong.
Can Lazy Eye Be Prevented?
In many cases, the vision loss associated with amblyopia can be prevented or reduced if the underlying problem is identified early.
This is why children's eye examinations are important, particularly when there is:
A family history of lazy eye or squint
A strong prescription in the family
A noticeable eye turn
Premature birth
A known eye condition
Concern about your child's vision
Early detection gives your child's visual system the best opportunity to develop normally.
At What Age Should a Child Have an Eye Check?
Children should have their eyes assessed during the early years, even if they appear to see normally. I suggest checking from age of 4 years old.
At The Eye Clinic by Dr Cheryl Lee, children's eye screening assesses vision, refraction, eye alignment, binocular vision and eye health. Our children's screening services are designed to identify problems such as amblyopia, refractive errors, eye alignment problems and myopia risk.
For young children, an eye examination can be particularly valuable because they may not know that their vision is abnormal.
How Is Lazy Eye Diagnosed?
Amblyopia is diagnosed through a comprehensive eye examination.
Depending on your child's age, the examination may include:
Visual acuity testing
Refraction to determine the spectacle prescription
Assessment of eye alignment
Assessment of how the two eyes work together
Examination of the front and back of the eyes
Assessment for conditions that may interfere with normal visual development
The important question is not simply “Does my child need glasses?”
It is also:
“Is each eye developing good vision, and are the two eyes working together properly?”
How Is Lazy Eye Treated?
Treatment depends on the cause and severity of the amblyopia.
Glasses
If a child has a significant refractive error, appropriate glasses may be the first and most important treatment.
Some children experience a substantial improvement in vision simply after wearing the correct prescription consistently.
Patching
If one eye is significantly weaker, the stronger eye may be covered with an eye patch for a prescribed period.
This encourages the brain to use the weaker eye.
Patching needs to be carried out consistently and according to the treatment plan recommended for your child.
Atropine Penalisation
In some children, atropine drops may be used in the stronger eye to temporarily blur its near vision.
This encourages the child to use the weaker eye.
Atropine is not suitable for every child, so treatment should be individualised following an eye examination.
Treating the Underlying Eye Condition
If amblyopia is caused by a cataract, drooping eyelid, significant eye misalignment or another eye condition, the underlying problem may need to be treated as part of the overall management.
Does Lazy Eye Get Better With Age?
Early treatment is important because the visual system is developing rapidly during childhood.
The brain has a greater ability to adapt and develop normal visual connections during the early years.
However, it is important not to assume that treatment is pointless simply because a child is older than seven.
The potential for improvement depends on factors including the child's age, the severity and type of amblyopia, whether treatment has been attempted previously and whether the underlying cause has been corrected.
Older children and teenagers may still benefit from treatment, so it is worth having the eyes assessed rather than assuming that it is too late.
What Happens If Lazy Eye Is Not Treated?
If amblyopia is not identified and treated during childhood, the weaker eye may remain permanently below its full visual potential.
This can affect:
Depth perception
Sports performance
Hand-eye coordination
Certain school activities
Future occupational options
It is therefore much better to identify and treat amblyopia as early as possible.
Can Adults Have Lazy Eye?
Yes.
Adults can have amblyopia that began during childhood.
However, the condition is different from simply developing blurred vision as an adult.
An adult who suddenly develops reduced vision in one eye should not assume that it is lazy eye. Sudden vision loss can have other causes and requires prompt assessment.
Lazy Eye vs Squint – What Is the Difference?
The terms are sometimes confused.
Lazy eye (amblyopia) means reduced vision caused by abnormal visual development.
Squint (strabismus) means the two eyes are not properly aligned.
A child with a squint can develop amblyopia, but not every child with amblyopia has an obvious squint.
A child can have a perfectly straight-looking eye and still have significant amblyopia.
Why Children's Eye Screening Matters
Children are remarkably good at adapting.
If one eye sees clearly and the other eye does not, a child may simply rely on the better eye and never complain.
That is why parents should not rely solely on their child's ability to report a vision problem.
At The Eye Clinic by Dr Cheryl Lee, children's eye screening looks beyond simply checking whether a child can read an eye chart. The assessment can identify refractive errors, amblyopia, eye alignment problems, binocular vision issues and other conditions that may affect visual development.
When Should My Child See an Eye Doctor?
You should arrange an eye examination if:
One eye appears to turn or wander
Your child frequently closes one eye
Your child tilts their head to see
Your child complains of blurred or double vision
There is a significant difference in the spectacle prescription between the eyes
Your child has difficulty with visual tasks
There is a family history of lazy eye or squint
You are concerned that your child does not see clearly
Your child has already been diagnosed with amblyopia and you would like a specialist assessment
Frequently Asked Questions About Lazy Eye
Is lazy eye the same as needing glasses?
No. Glasses correct focusing problems such as myopia, hyperopia and astigmatism. Amblyopia is reduced vision caused by abnormal visual development. Glasses may be an important part of treating amblyopia, but they do not always completely correct the problem.
Can a child outgrow lazy eye?
Amblyopia should not simply be left to improve on its own. Early diagnosis and appropriate treatment give the best opportunity for the weaker eye to develop better vision.
Does patching really work?
Patching can be an effective treatment for many children with amblyopia. The amount of patching required depends on the child's individual condition and I would take into account many factors.
How long does a child need to wear an eye patch?
There is no single answer. Treatment is individualised according to the severity of the amblyopia and the child's response to treatment.
Can lazy eye come back after treatment?
Some children may experience a reduction in vision again after successful treatment. Follow-up examinations are therefore important.
Can lazy eye be treated in teenagers?
Treatment may still be beneficial in older children and teenagers. The likelihood and extent of improvement varies between individuals, so an assessment is worthwhile rather than assuming that treatment will not work.
Can lazy eye be treated in adults?
Amblyopia that began in childhood is more difficult to treat in adulthood because visual development has largely matured. However, the appropriate approach depends on the individual, and an adult with reduced vision in one eye should first have a proper eye examination to confirm the diagnosis.
Children's Eye Care at The Eye Clinic by Dr Cheryl Lee
At The Eye Clinic by Dr Cheryl Lee, we provide personalised eye care for children and adults in Singapore.
For children, our assessment can look at vision, spectacle prescription, eye alignment, binocular vision and overall eye health. Early identification of problems such as amblyopia allows appropriate treatment or monitoring to begin when it is most helpful.
If you are concerned that your child may have a lazy eye, an eye examination can determine whether the problem is amblyopia, a refractive error, an eye alignment problem or another condition affecting vision.