Strabismus, commonly referred to as crossed eyes, is a condition where the eyes do not align properly, often affecting children from a young age. This misalignment can lead to significant challenges in vision development and also may affect learning and school performance as well as social and psychological well-being. For parents and caregivers, understanding the implications of pediatric strabismus is crucial, as early diagnosis and intervention can make a difference in outcomes.
Why Does Strabismus Occur in Children?
Pediatric strabismus can appear at any age, including at, or shortly after, birth.
The brain and the six different muscles around each eye work together to control eye movements. The brain processes visual information and sends signals to the eye muscles to ensure that both eyes align with each other and move in a coordinated manner. It uses the information generated from both eyes to create a single, cohesive image that includes depth perception. The eye muscles allow the eyes to move up, down, left, and right, and to rotate.
Any disruption in the brain’s signals or the eye’s muscles can result in imbalances that lead to strabismus.
Some examples include:
- Refractive errors: Differences in vision between the two eyes can cause the brain to struggle with merging images.
- Family history: Strabismus has a hereditary component, which means a child is at a higher risk of developing the condition if a parent or sibling also has it.
- Congenital disorders: Some children are born with conditions that affect the neuromuscular control of the eyes, such as Duane syndrome or Brown syndrome.
- Neurological disorders: Cerebral palsy or Down syndrome can affect the brain’s ability to coordinate eye movements.
- Brain injuries: Any trauma or injury to the brain, especially in areas responsible for vision and eye movement, can disrupt normal eye alignment.
In newborns, occasional eye wandering or crossing is normal during the first few months. There is also a condition called pseudostrabismus, which is an illusion of inward turning of the eyes caused by facial features such as a wide nasal bridge or epicanthal folds. These folds of skin cover the inner corner of the eye and can make the eyes look crossed or misaligned, especially in photographs or certain lighting conditions.
Types of Strabismus
Strabismus in children is categorized by the direction in which one or both eyes turn:
- Esotropia: This occurs when one or both eyes turn inward. It is the most common type of strabismus in young children.
- Exotropia: This occurs when one or both eyes turn outward, usually intermittently when a child is tired or focusing on distant objects.
- Hypertropia: This occurs when one eye turns upward
- Hypotropia: This occurs when one eye turns downward.
Strabismus Treatments
Strabismus in children can be addressed with a range of treatment options, with the end goal of straightening the eyes so they work together to produce clear vision and allow the child to develop normal peripheral vision and depth perception.
Corrective lenses
- Glasses correct refractive errors, provide clear vision, and reduce over focusing in farsighted individuals.
- In some cases, prism lenses help bend light entering the eyes to improve alignment and alleviate double vision.
Occlusion therapy or Patching
- The stronger eye is covered with a patch, forcing the weaker eye to develop better vision, which can help align the eyes over time.
- When vision is normal or strabismus is intermittent, patching can improve the brain’s control of the alignment of the eyes.
- Depending on the severity, the eye patch is worn for several hours a day for months or even years.
Orthoptic exercises
- Specialized exercises are designed to improve the coordination and strength of the eye muscles, helping to align the eyes properly.
- Exercises include viewing partially similar objects simultaneously, computer-based programs with visual tasks and games, and pencil push-ups.
Botox injections
- Botulinum toxin injections work by blocking the nerve signals that cause muscle contraction, leading to temporary muscle relaxation and improvement in alignment.
- The effects are temporary, although they may last a few months, or in some cases even longer.
Strabismus eye surgery
- Surgery involves a small incision in the membrane that covers the eye’s surface, which allows your ophthalmologist to access the muscle.
- They will either shorten the muscle (resection) to make it stronger, weaken amuscle (recession) by detaching the muscle and reattaching it farther back in the eye, or repositioning a muscle to help the eyes be aligned.
- Strabismus surgery can restore eye alignment and reduce or eliminate double vision.
- Children sometimes require multiple surgeries to fully correct the misalignment.
What Happens if Strabismus is Left Untreated?
If strabismus is left untreated in children, it can lead to several complications and long-term effects, ranging from the development of a lazy eye to double vision.
Amblyopia (lazy eye): The longer eye misalignment continues, the more the brain starts to ignore signals from the less dominant eye to avoid double vision. This results in reduced vision in that eye, which may be permanent.
Loss of depth perception: Proper eye alignment is essential for depth perception, and untreated strabismus can hinder this, making distance judgment challenging.
Double vision: When the eye muscles don’t work together, each eye can capture a different image which the brain cannot merge into a single cohesive picture.
Decrease in peripheral vision: Especially when the eyes are turned inward, the patient’s peripheral, or side, vision will be decreased.
