One or both eyes can be affected by amblyopia, which is also called the lazy eye because the brain ignores the input from the weaker eye and relies only on the stronger one. Those suffering from amblyopia may experience poor depth perception, blurred vision, double vision, squinting, and head tilting, along with permanent vision loss.
In some cases, amblyopia is present at birth due to genetic or structural problems in the eyes. In other cases, it develops later in childhood due to other vision problems or environmental factors that affect the brain's ability to process visual information.
Some of the possible causes of amblyopia are:
Refractive errors: These are common vision problems like nearsightedness (having trouble seeing far away), farsightedness (having trouble seeing things up close), and astigmatism (having trouble seeing things up close). Glasses or contacts can usually fix these problems. However, if they are not treated, the brain may rely more on the eye with stronger vision1.
In strabismus, the eyes do not line up correctly and move in different directions. One eye might drift inwards or outwards, up or down. This can cause double vision and make it difficult for the brain to focus equally on both.
As the lens of the eye becomes cloudy, this affects how light enters the eye. Cataracts can cause blurry vision and reduce contrast sensitivity. They can also interfere with normal eye movements.
A media opacity occurs when light cannot reach one or both eyes due to an injury, infection, or congenital defect. For example, cataracts can be caused by an injury or infection to the eye's lens. Other examples include tumors, inflammation, glaucoma, or congenital defects affecting the eyelids or eyelashes.
A child who rubs his or her eyes with their hands or objects like pencils or crayons can damage the surface of the eye, cause scarring, and affect how light enters the eye.
The symptoms of amblyopia may vary depending on which eye is affected and how severe it is. Some children may not notice any symptoms until they are older or have an eye examination by an ophthalmologist (an eye doctor who specializes in treating vision problems). Some of the common symptoms of amblyopia are:
Poor depth perception: This means having difficulty telling how near or far something is.
Blurred vision: This means having difficulty seeing details clearly.
Double vision: This means seeing two images of one object instead of one.
Squinting: This means closing one eye partially to see better.
Tilting head: This means tilting one side of their head towards their affected eye.
Crossing eyes: This means having one pupil aligned with another instead of being in line with each other.
Droopy eyelid: This means having one eyelid lower than normal.
Various tests are performed by an ophthalmologist to determine if there is any underlying cause for amblyopia and how well each eye functions.
Some of the tests that may be done are:
Examination of both eyes: The ophthalmologist will look for signs of refractive errors, strabismus, cataracts, media opacities, corneal abnormalities (such as dryness), conjunctival abnormalities (such as redness), eyelid abnormalities (such as drooping), pupil abnormalities (such as size), iris abnormalities (such as color), lens abnormalities (such as shape), retina abnormalities (such as detachment), optic nerve abnormalities (such as swelling), macula abnormalities (such as scarring), etc.
Charts with letters or numbers will be used by the ophthalmologist to measure each child's visual acuity at different distances.
Stereopsis test: The ophthalmologist will measure how well each child can perceive depth using charts with shapes that have different orientations.
Eye movement test: The ophthalmologist will observe how each child moves their eyes while looking at different targets using special devices called oculometers.
Eye alignment test: The ophthalmologist will check how well each pair of eyes moves together using special devices called alignometers.
Eye patching test: The ophthalmologist will ask each child to wear an occlusive patch over their affected eye for several hours every day for several weeks to see if there is any improvement in their vision.
A child's age and cooperation, along with the cause and severity of amblyopia, determine how amblyopia is treated. During treatment, the weaker eye's vision will be improved, any visual imbalance between the eyes will be reduced or eliminated, and any permanent damage to the eye system will be prevented.
Some of the common treatment options for amblyopia are:
Amblyopia can be corrected with glasses or contact lenses that correct nearsightedness, farsightedness, or astigmatism. Corrective eyewear can also align the eyes and improve their focus.
The child wears an eye patch over the eye with better vision several hours a day in order to stimulate the weaker eye. In addition to reducing any visual imbalance between the eyes, eye patching can help prevent further vision deterioration. For children younger than 7 years old or who have not responded well to other treatments, eye patching is usually recommended.
The Bangerter filter blurs the stronger eye and works like an eye patch to stimulate the weaker eye by placing it on the eyeglass lens of the stronger eye. Children who have strabismus (crossed eyes) or other ocular misalignment problems that affect their binocular vision usually use Bangerter filters.
Atropine (Isopto Atropine) eyedrops temporarily blur the stronger eye's vision. This can encourage children to use more of their weaker eye and improve their binocular vision. Depending on the doctor's recommendation, eyedrops are usually prescribed for use on weekends or daily.
It may be necessary to undergo surgery to correct any underlying causes of amblyopia, such as droopy eyelids or cataracts that block light from reaching one or both eyes. Strabismus problems may also require surgery to be corrected.
The duration and frequency of treatment may vary based on each child’s condition and response. Some children may only need treatment for a few weeks or months, while others may need treatment for several years. It is important to check in regularly with an ophthalmologist (an eye doctor who specializes in treating vision problems) and monitor any changes in vision.
Amblyopia can be prevented by early detection and treatment of any vision problems that may affect its development. Some of the preventive measures that can be taken are:
Frequent eye exams: Regular check-ups with an ophthalmologist can help to identify any signs of refractive errors, strabismus, cataracts, media opacities, corneal abnormalities (such as dryness), conjunctival abnormalities (such as redness), eyelid abnormalities (such as drooping), pupil abnormalities (such as size), iris abnormalities (such as color), lens abnormalities (such as shape), retina abnormalities (such as detachment), optic nerve abnormalities (such as swelling), macula abnormalities (such as scarring), etc. These conditions can cause amblyopia if left untreated.
Children should wear protective eyewear when playing sports or doing activities that involve flying objects, dust, chemicals, or bright lights. Protective eyewear can prevent injuries or infections that may affect their eyes.
Rub your eyes rarely: Rub your eyes frequently with your hands or with objects like pencils or crayons to cause scarring or inflammation that affects how light enters your eyes. In addition to causing infection or irritation, rubbing your eyes can introduce foreign objects into your eyes.
Maintaining good posture: Poor posture can affect the alignment of the eyes and strain the muscles around them. Using ergonomic furniture, devices, and activities can help to prevent the problems associated with poor posture, including head tilting or tilting towards one side, which can worsen strabismus.
You can help your child have healthy and clear vision for a lifetime by following these preventive measures and seeking timely medical attention if necessary.
