Amblyopia (Lazy Eye)

Amblyopia, often called lazy eye, is a vision condition that develops in infancy and childhood. Amblyopia occurs when one eye does not have normal visual acuity, even with prescription eyeglasses or contact lenses. Lazy eye typically affects one eye, but both eyes can have decreased visual acuity in certain cases.

Early diagnosis in childhood and appropriate treatment can prevent vision loss caused by amblyopia. If left untreated, lazy eye can lead to significant visual impairment in the affected eye.

Potential Causes of Amblyopia

Amblyopia is the most common cause of visual loss in children and adolescents in developed countries, affecting three to four percent of school-aged children. The exact cause of amblyopia is often unknown.

Normally, the brain uses nerve impulses from both eyes to perceive vision. However, if there is a problem that impairs vision in one eye, the brain may compensate by relying more on the stronger eye and ignoring signals from the weaker eye.

Common Causes of Amblyopia

1. Refractive errors: Can be corrected with glasses or contacts. If left untreated, the brain may rely more on the stronger eye.
2. Nearsightedness (difficulty seeing far away)
3. Farsightedness (difficulty seeing up close)
4. Astigmatism (blurred vision)
5. Strabismus (crossed eye):
6. The eyes do not align.
7. One or both eyes are misaligned, causing the brain to suppress the vision from the deviated eye and preventing normal vision development.
8. Anisometropia:
9. Significant difference in prescription or size between the eyes.
10. The brain prioritizes signals from the eye with better vision, while the other eye does not have to function.
11. Cataract: Causes cloudiness in the lens of the eye, resulting in blurry vision. Although most cataracts occur in older adults, newborns and children can also develop cataracts.
12. Failure to use glasses: Not wearing prescribed glasses can contribute to the development of lazy eye. It is one of the most common causes and often goes undiagnosed.

Other possible causes of amblyopia include:

• Obstructions in the visual axis
• Corneal opacity
• Ptosis (droopy eyelid)
• Retinal diseases that affect image projection to the brain
• Trauma
• Scarring
• Vitamin A deficiency
• Glaucoma

Risk Factors of Amblyopia

Factors that increase the risk of amblyopia include:

• Premature birth
• Low birth weight
• Family history of amblyopia
• Developmental disabilities
• Significant difference in prescription between the eyes

Is Amblyopia Brain Damage?

The development of amblyopia is associated with developmental disorders and brain abnormalities. It occurs due to impaired neural pathways in the brain that process vision. The disorder arises when both eyes are not used equally.

Signs and Symptoms of Amblyopia

The main symptom of amblyopia is blurred vision. Infants and children may not be aware of the condition and do not complain about it. Even if amblyopia is present, the affected eye may appear normal.

Common signs and symptoms of amblyopia include:

• Crying or fussing when one eye is covered
• Covering one eye
• Tilting the head
• Getting closer to objects
• Frequent bumping into things (poor depth perception)
• Misaligned eyes
• Double vision or poor overall vision
• Difficulty catching and throwing objects
• Inattentiveness
• Poor eye-hand coordination
• Increased clumsiness
• Difficulty with micro-eye movements
• Slower reading speed and comprehension
• Droopy eyelid
• Eye strain
• Headaches

Since amblyopia usually stems from problems with vision development in infancy, it can be challenging to identify the symptoms. If your child fusses or struggles when one of their eyes is covered, this could be a sign of amblyopia. Schedule an appointment with an eye doctor to have your child’s eyes examined and ensure their eye health.

Diagnosis of Amblyopia

Amblyopia can often go undiagnosed without an eye examination.

Tests used to diagnose amblyopia include:

• Visual acuity: Measures vision by reading letters on an eye chart. Young children may be examined using images.
• Motility exam: Checks eye alignment and identifies any muscle dysfunction.
• Refraction: Determines the correct lens power needed to compensate for refractive errors such as nearsightedness, farsightedness, or astigmatism by placing different lenses in front of the eyes.

Treatment Options for Amblyopia

Amblyopia requires immediate treatment as it does not improve without intervention. The recommended treatment options vary depending on the underlying cause.

• Vision therapy:

• Eye exercises that encourage both eyes to work together. Amblyopia exercises aim to stimulate the brain to recognize the weaker eye, thus improving vision in that eye.
• Sometimes, a patch is applied to the stronger eye, forcing the weaker eye to work harder and develop stronger visual acuity. The patch is typically worn for a few hours each day.
• Treatment duration may range from weeks to months, depending on the severity. In cases where a child refuses to wear a patch, a prosthetic contact lens that blocks vision in the stronger eye is an alternative.

Outlook for Children with Lazy Eye

Lazy eye is treatable, and treatment can lead to improved vision. Treatment may be necessary throughout childhood, and regular follow-up appointments are crucial. The frequency of follow-up appointments varies based on the child’s age, symptoms, and the severity of the condition.

When is it Too Late to Treat Lazy Eye?

Untreated amblyopia can lead to permanent vision loss and reduced depth perception in the affected eye. Amblyopia treatment initiated before the age of nine often results in significant improvement in the weaker eye. The critical period for treating amblyopia is between three and six years of age.

Preventing Lazy Eye or Amblyopia

Early detection and treatment of conditions such as astigmatism, cataracts, and strabismus can help prevent amblyopia.

If you or your child has a family history of lazy eye and falls into the at-risk group for amblyopia, it is recommended to discuss preventive measures with your doctor.

Tips for preventing lazy eye include:

• Regular eye examinations: Parents should ensure regular eye exams for their children as the most effective way to prevent lazy eye. Children may not recognize the signs, so parents must take the initiative to schedule routine eye exams.
• Wearing prescribed glasses: If a child younger than seven years old needs glasses, they should be encouraged to wear them to promote optimal eyesight development. After the age of eight, vision becomes stable and does not typically change.
• Cataract surgery: If a cataract is causing a child’s amblyopia, surgical removal may be recommended to restore vision.