When Eyes Don't Align: What Is Strabismic Amblyopia

Vision plays a vital role in how patients interact with the world. But when the eyes don’t align properly, it can affect a patient’s sight and depth perception. One common condition related to eye misalignment is strabismic amblyopia, a type of lazy eye caused by strabismus (eye misalignment).

Understanding the causes, symptoms, and treatment options for this condition can help patients take proactive steps to protect their vision and overall eye health.

Amblyopia is colloquially referred to as "lazy eye." It is a condition where vision in one eye has blurry, unfocused vision, while the other eye can see clearly. As amblyopia progresses, the brain begins to ignore the blurry eye in favor of the one with clear vision. This leads vision to further deteriorate in the affected eye.

Amblyopia typically develops in early childhood, between birth and age 7, when the visual system is still maturing. As the condition worsens with time, parents should seek medical attention from an eye care specialist if they notice symptoms in their child.

Strabismic amblyopia is a condition in which the brain favors one eye over the other due to misalignment, leading to reduced vision in the weaker eye. This occurs when the brain suppresses visual input from the misaligned eye to prevent double vision, ultimately causing that eye to become weaker over time.

Strabismic amblyopia is the most common type of amblyopia and occurs when the eyes are not properly aligned. If left untreated, this condition can lead to long-term vision problems, including depth perception issues, lost visual acuity, and permanent vision loss in the weaker eye.

While strabismic amblyopia is a specific type of amblyopia, not all cases of amblyopia are caused by eye misalignment. Amblyopia can develop for different reasons. For instance, anisometropic amblyopia occurs when one eye has a significantly different prescription than the other, causing the brain to rely more on the stronger eye.

Deprivation amblyopia is caused by conditions such as congenital cataracts that block vision in one eye during critical developmental years. Refractive amblyopia is caused by having a high amount of error in the focusing system.

Despite these differences, all forms of amblyopia share a common trait. If left untreated, the brain adapts to favor one eye, leading to long-term impairment in binocular vision and altered stereoscopic visual acuity.

This type of amblyopia is primarily caused by strabismus, a condition where one eye turns inward, outward, upward, or downward instead of aligning properly with the other eye. This misalignment prevents both eyes from working together as a team.

Over time, the brain adapts to using only the dominant eye, and the weaker eye loses its ability to process visual information effectively. This suppression can become permanent if not addressed early, making intervention crucial during childhood, when the brain’s adaptability is highest.

Several factors can contribute to the development of amblyopia caused by misalignment. Some key risk factors include:

• Congenital strabismus: Some babies are born with misaligned eyes, making them more prone to developing amblyopia.
  

• Uncorrected refractive errors Significant differences in vision between the two eyes can contribute to amblyopia development.
  

• Family history If a parent or sibling has strabismus or amblyopia, a child is at greater risk.

• Premature birth or low birth weight These factors are linked to a higher likelihood of developing amblyopia.

• Neurological conditions: Some brain-related disorders can affect eye coordination and alignment.

Since strabismic amblyopia develops early in life, early diagnosis and intervention are crucial to prevent long-term vision impairment.

The symptoms can vary depending on the severity of the misalignment and the extent of vision suppression. Common symptoms include:

• One eye drifting.

• Poor depth perception.

• Squinting or closing one eye to see better.

• Frequent tilting of the head to compensate for misalignment.

• Blurry vision in one eye.

• Difficulty with reading or hand-eye coordination.

• Eyestrain or headaches after visual activities.

In some cases, parents may not notice any obvious signs of amblyopia, as the child may unconsciously rely on the stronger eye. This makes routine eye exams essential for early detection.

A diagnosis typically involves a comprehensive eye exam. The exam will typically begin with a visual acuity test where the eye doctor measures how clearly each eye can see letters or images.

Next, patients may receive a cover test to determine how well the eyes work together by covering and uncovering each. Depending on the patient and course of the condition, doctors may also conduct a Refraction test to assess whether glasses or contact lenses are needed. And an ocular alignment test to examine how well the eyes track together.

Strabismic amblyopia is treatable, especially if addressed early in childhood. The goal of treatment is to strengthen the weaker eye and encourage both eyes to work together:

A patch is placed over the stronger eye, forcing the brain to rely on the weaker eye.This stimulates visual development and strengthens the misaligned eye. The patch is worn for a few hours each day over several weeks or months.

These are exercises and activities a patient does to improve eye coordination, focus, and depth perception, especially in the weaker eye.

This treatment is used as an alternative to patching. Atropine drops blur vision in the stronger eye, encouraging use of the weaker eye. This is beneficial for children who resist wearing an eye patch.

Corrective lenses can help address refractive errors that may be contributing to strabismic amblyopia. If one eye has significantly poorer vision, glasses or contacts may help balance the visual input.

In cases where eye misalignment is severe, strabismus surgery may be necessary to adjust the eye muscles and improve alignment. Surgery alone does not cure strabismic amblyopia, but it can help both eyes work together more effectively.

Early treatment leads to the best outcomes. The earlier strabismic amblyopia is diagnosed, the more successful treatment will be.

Routine eye exams are essential for treating the conditions. Parents should schedule pediatric eye screenings for their child at 6 months, 3 years, and before starting school. Untreated amblyopia can lead to permanent vision impairment, so it’s crucial to follow through with treatment recommendations.

Strabismic amblyopia typically develops in childhood, when the brain is still adapting to visual input. By adulthood, the brain’s plasticity decreases, making amblyopia treatment less effective.

However, some adults with untreated strabismic amblyopia may still benefit from vision therapy, corrective lenses, or surgery. For adults experiencing new-onset eye misalignment, it’s important to rule out neurological conditions such as stroke, multiple sclerosis, or head trauma.