Amblyopia — Know It All!

Editorial

All you need to know about Lazy Eye.

Know your ailment well, so you can manage it better!!

Here we come with Amblyopia today!

What is Amblyopia?

Amblyopia is also known as Lazy Eye.

Amblyopia (also known as lazy eye) is a form of poor vision that occurs in only 1 eye. It develops when there is a breakdown in how the brain and the eye work together, and the sight from 1 eye can not be recognised by the brain. The brain depends increasingly on the other, stronger eye over time, while vision gets worse in the weaker eye.

It’s called “lazy eye” because it works better with a stronger eye. But people with amblyopia are not lazy, and the way their eyes work can’t be controlled.

Amblyopia begins in infancy, and in children, it is the most common cause of vision loss. Up to 3 children out of 100 have it. The good news is that early treatment works well and prevents problems with long-term vision generally.

What Causes Amblyopia?

The lazy eye develops early in life due to abnormal visual experience that alters the nerve pathways at the back of the eye and the brain between a thin layer of tissue (retina). There are fewer visual signals received by the weaker eye. The ability of the eyes to function together gradually decreases and the brain suppresses or rejects feedback from the weaker side.

The lazy eye will result in something that blurs the vision of a child or causes the eyes to cross or face black. Common causes of the disorder include:

Imbalance of the Muscles (strabismus amblyopia). A deficiency in the muscles that position the eyes is the most frequent source of lazy eyes. This imbalance can result in the eyes crossing in or turning out and prevent them from working together.

The difference in vision sharpness between eyes (refractive amblyopia). The lazy eye can result in a significant difference between the prescriptions in each eye, often due to farsightedness, but sometimes due to nearsightedness or an uneven eye surface curve (astigmatism).

Usually, glasses or contact lenses are used to correct these issues of refraction. In some children, a combination of strabismus and refractive problems causes lazy eyes.

Deprivation. Deprivation A problem with one eye can forbid clear vision in that eye, such as a cloudy area in the lens (cataract). Deprivation of childhood amblyopia requires immediate surgery to avoid irreversible loss of vision. Sometimes, it is the most extreme form of amblyopia.

What are the symptoms of Amblyopia?

Signs and symptoms of lazy eye include:

  • An eye that wanders inward or outward
  • Eyes that appear to not work together
  • Poor depth perception
  • Squinting or shutting an eye
  • Head tilting
  • Abnormal results of vision screening tests

Sometimes a lazy eye is not evident without an eye exam.

What are the Complications of Amblyopia?

  • Untreated, lazy eye can cause permanent vision loss.

What are the Risk Factors for Amblyopia?

Factors associated with an increased risk of lazy eye include:

  • Premature birth
  • Small size at birth
  • Family history of lazy eye
  • Developmental disabilities

Refractive errors: These conditions affect how light passes through the eye. They include:

  • Nearsightedness (myopia), trouble seeing far away.
  • Farsightedness (hyperopia), trouble seeing up close.
  • Astigmatism, a curved cornea.

Strabismus (crossed eyes): The eyes are meant to move together as a pair, but sometimes they don’t. If one drifts (in, out, up or down), the brain may rely on one eye over the other, leading to amblyopia.

Structural problems: Sometimes, the eye has a structural problem that can lead to amblyopia, including:

  • Cataracts, which cause cloudiness in the lens and blurry vision.
  • Astigmatism.
  • Droopy eyelid.
  • Scar on the cornea.

How is Amblyopia diagnosed?

The odds of a complete recovery are improved by early diagnosis. The American Optometric Association advises that before 6 months of age and again before they are 3 years old, kids get a comprehensive vision screening.

What checks will be made to get amblyopia diagnosed?

For amblyopia, a paediatrician, school vision service, optometrist or ophthalmologist may assess the vision of an infant.

The screener is allowed to:

  • Place drops in the eye to make it larger for the pupil.
  • Flash each eye with a candle.
  • Cover one eye at a time to test whether a moving target can be tracked by each eye.
  • On the other side of the bed, ask older children to read letters on a map.

A vision test decides:

  • Can the eyes cause light to come through all the way?
  • Do the eyes both see equally well?
  • Are the eyes correctly moving? Do they move together?
  • Were the eyes positioned appropriately?
  • Can the two eyes differ in vision?
  • Is one eye floating or wandering?
  • With an illuminated magnifying tool, are any cataracts visible?

What is the treatment for Amblyopia?

As the complex relations between the eye and the brain are emerging, it is important to start therapy for the lazy eye as soon as possible in childhood. When therapy begins before age 7, the strongest outcomes appear, while half of the children between the ages of 7 and 17 respond to treatment.

The choices for treatment depend on the cause of the lazy eye and on how much the disease impacts the vision of your infant. Maybe your doctor would recommend:

  • Eyewear corrective. Glasses or contact lenses can fix issues that occur in lazy eyes, such as nearsightedness, farsightedness or astigmatism.
  • Patches for eyes. Your infant wears an eye mask over the eye for an improved vision for two to six or more hours a day to stimulate the weakened eye. In rare cases, wearing an eye patch for too long can cause the patched eye to develop amblyopia. It’s generally reversible, though.
  • Bangerter filter. This special filter is mounted on the stronger eye glass lens. The filter blurs the more powerful eye and acts to stimulate the weaker eye, like an eye patch.
  • Eyedrops. Yes. An eye drop of a drug called atropine (Isopto Atropine) in the stronger eye can momentarily blur vision. Usually prescribed for the weekend or daily use, the use of drops encourages the weaker eye to be used by your child and provides an alternative to a patch. Side effects include sensitivity to light and eye irritation.
  • Surgery. Your child might need surgery if he or she has droopy eyelids or cataracts that cause deprivation amblyopia. If your child’s eyes continue to cross or wander apart with the appropriate glasses, your doctor might recommend surgical repair to straighten the eyes, in addition to other lazy eye treatments.
  • Activity-based treatments — such as drawing, doing puzzles or playing computer games — are available. The effectiveness of adding these activities to other therapies hasn’t been proved. Research into new treatments is ongoing.

For most children with lazy eye, proper treatment improves vision within weeks to months. Treatment might last from six months to two years.

It’s important for your child to be monitored for recurrence of the lazy eye — which can happen in up to 25 percent of children with the condition. If lazy eye recurs, treatment will need to start again.

References:

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https://www.mayoclinic.org/diseases-conditions/lazy-eye/symptoms-causes/syc-20352391

https://my.clevelandclinic.org/health/diseases/10707-amblyopia-lazy-eye

https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/amblyopia-lazy-eye

https://www.webmd.com/eye-health/amblyopia-child-eyes#1

https://www.aao.org/eye-health/diseases/amblyopia-lazy-eye