Strabismus (Crossed Eyes)
Strabismus, commonly referred to as crossed eyes, is a vision condition where both eyes do not align to focus on the same object at the same time. This occurs when one or both eyes drift inward, outward, upward, or downward either occasionally or consistently.
Strabismus is a significant issue related to eye coordination, a crucial aspect of visual function. Since both eyes fail to focus on the same point, the brain struggles to merge the separate images into a single three-dimensional visual perception.
Causes of Strabismus
Strabismus occurs when an individual has difficulty developing proper eye coordination. Infants typically develop this skill within the first few months after birth, and it continues to evolve alongside sensory and motor functions over the years.
The exact cause of strabismus is often unclear. However, it can be associated with genetic factors, developmental delays, or other vision-related issues.
- In Children: Strabismus is most commonly diagnosed before the age of six, often appearing as early as three years old. However, it can manifest at any age.
- In Older Children & Adults: Strabismus can develop later in life, sometimes due to excessive visual strain from tasks such as reading or using digital screens. A sudden onset in adults should be evaluated immediately as it could indicate an underlying health issue.
Types of Strabismus
Several factors determine the type of strabismus, including:
1. Direction of Eye Misalignment
The direction in which the eye turns is categorized as:
- Esotropia: Inward turning
- Exotropia: Outward turning
- Hypertropia: Upward turning
- Hypotropia: Downward turning
- Cyclotropia: Rotational misalignment
Among these, esotropia and exotropia are the most prevalent forms of strabismus. Some individuals may experience a combination, such as an inward and downward turn simultaneously.
2. Frequency of Eye Misalignment
Strabismus can either be:
- Constant: The eyes are always misaligned.
- Intermittent: The misalignment occurs only at certain times, such as when reading or looking at distant objects.
Intermittent strabismus is generally easier to manage and treat.
3. Affected Eye
Strabismus may involve one eye or both. Surprisingly, when both eyes alternate in misalignment, it often indicates a better visual balance compared to cases where only one eye is affected.
4. Severity of Eye Turn
The degree of eye misalignment can range from mild to severe. While a more noticeable misalignment may not necessarily be harder to treat, it is a crucial factor in designing an effective treatment plan.
5. Sensory Adaptations
When the eyes fail to align properly, the brain tries to adapt by:
- Causing double vision, which may be intermittent or persistent.
- Suppressing vision in one eye to reduce confusion.
- Developing anomalous correspondence, where the brain incorrectly aligns the images from each eye..
A comprehensive eye examination helps classify the specific type of strabismus using these factors. For example, a diagnosis might be “30-diopter Right Constant Esotropia with Suppression.”
Symptoms of Strabismus
Patients with strabismus may not always be aware of their symptoms, especially if they have developed suppression to avoid double vision. However, those with intermittent misalignment are more likely to experience noticeable symptoms such as:
- Eye strain or discomfort
- Frequent headaches
- Double or blurry vision
- Visual fatigue, particularly when reading or focusing for long periods
Treatment Options for Strabismus in Children and Adults
The first step in managing strabismus is ensuring the patient has the correct eyeglass prescription. Developmental optometrists conduct specialized tests to determine whether corrective lenses can help alleviate visual stress and improve eye coordination. In some cases, especially with accommodative esotropia, wearing the right prescription can significantly reduce or eliminate eye misalignment.
Visual Stress Reduction & Hygiene
Adjusting environmental factors and habits can play a role in reducing visual stress. Strategies include proper lighting, taking regular breaks during near work, and maintaining an optimal reading distance.
Vision Therapy
Depending on the severity and goals of treatment, vision therapy may be recommended. Strabismus treatment falls into two categories:
- Functional Improvement: Aims to reduce symptoms and enhance visual comfort, though the misalignment may still persist.
- Complete Correction: Focuses on fully aligning the eyes and developing binocular vision. The success rate depends on the type of strabismus and the patient’s response to therapy.
The developmental optometrists at Nandadeep Eye Hospital thoroughly discuss all available treatment options with patients following a functional vision examination, ensuring the most suitable approach is chosen.
Conclusion
Strabismus is a complex vision condition that can impact individuals of all ages. Early diagnosis and intervention significantly improve treatment outcomes, whether through corrective lenses, vision therapy, or lifestyle modifications. If you or your child experience symptoms of strabismus, consulting a developmental optometrist is essential for a tailored treatment plan.