STRABISMUS(CROSSED EYES); CAUSES AND TREATMENT
Strabismus, commonly also known as Crossed eyes, is a condition whereby the two eyes of an individual do not align and causes each of the eyes to focus differently at objects in sight. It is more common in children, it may also occur later in life due to secondary causes such as trauma or brain injury, etc. When the eye turns inward, it is called esotropia and exotropia when turned outward. When turned upward, we term it hypertropia and hypotropia when turned downward.
An individual experiencing crossed eyes may present with one or all of the following signs and symptoms:
- One of eyes pointing inward or outward (this is called a deviation), while the other one is looking normal. In some cases however, both eyes may both appear deviated with each looking in different directions.
- Diplopia (or double vision) in most cases is reported by one who is suffering from crossed eyes, especially in severe cases. Both eyes are meant to capture similar images for the brain to interpret as a single better quality image in a process called Binocular Single Vision. But when crossed eyes is present, and the two eyes are fixating on different objects in the outer world, thereby presenting two different images to the brain, this in turn causes diplopia or confusion.
- Reduced vision in the eye where deviation is present.
- Reduced depth of focus: People with crossed eyes tend to have poor judgement of distance of an object.
- Headaches may also be reported by a person experiencing crossed eyes.
Clinical procedures required to aid the diagnosis of crossed eyes or strabismus include:
- Visual acuity test to determine how well the person can see at far and near both unaided (without corrective lenses in place) and also the current prescription of the person in place.
- Cover uncover test to determine the extent of deviation.
- Direct Ophthalmoscopy to examine the retina and it's important structures especially the macular.
- Optical Coherent Tomography (OCT) to investigate any abnormal activity in the macular ( the point where sharpest image is been formed) and optic nerve head (the point where visual impulses are been transmitted to the brain for interpretation).
- MRI and CT scans to investigate any underlying secondary causes of the crossed eyes, such as; cerebral palsy, tumor or nerve damage.
Anyone having any of the following is at risk of having a crossed eyes:
- A positive family history of crossed eyes.
- Stroke or any form of brain injury.
- Lazy eye or amblyopia in one or both eyes.
- Damaged retina or macular.
- Poor or no vision in one eye may cause the affected eye to deviate.
- Brain tumors or any other form of brain disorders.
- Diabetic patients that have developed complications in the eye may also develop a crossed eyes later.
Causes of Crossed Eyes
Crossed eyes in children is called infantile strabismus and is often times idiopathic, that is the cause is unknown. In other times, infantile strabismus may be from trauma induced at birth.
Crossed eyes that occurs later in life is usually from either of the following:
- Long standing uncorrected refractive error especially when it is more severe in one eye than the other. This causes the affected eye to get suppressed by the brain, which can in turn cause the eye to be lazy (amblyopia) then eventually result in a deviated eye.
- When the two eyes no longer work in unison due to an impaired nerve or eye muscle.
- Due to stroke or cerebral palsy.
- Physical injury or trauma to the eye, especially one that affects the brain.
Treatment of Crossed Eyes
Treatment plan that will be recommended by your eye doctor for crossed eyes depends on the severity and the underlying cause of the condition. Below are some of the options an eye doctor may explore in the management of strabismus:
- Eye exercises or orthoptics: this is a form of therapy carried out by a specialist (an orthoptist), aimed at reviving the defaulting muscles responsible for the crossed eyes. It involves a series of exercises that will mostly be carried out by the sufferers themselves ranging from simple to comeplex ones. Therapy can also be based on appointments to the specialist's office.
- Giving corrective lenses if the cause is as a result of an uncorrected refractive error. This option includes eye spectacles and contact lenses. Prisms may be also incorporated in prescription lenses to align the eyes.
- Surgery to correct the defaulted muscles.
- Use of eye patches. This is used when the crossed eyes is caused by amblyopia. The eye patch is worn over the good eye in order to force the bad eye to see in the absence of the good eye.
Your eye doctor may want to combine these options depending on the severity of the condition, for a better result.
Strabismus or crossed eyes or 'a squint’ is a condition where there is misalignment in one or both eyes and the two eyes are not focusing at the same direction. The may appear turned inward, outward, upward or downward. The condition can be constant or intermittent.
If there is anyone that has had any of the signs of crossed eyes or has had an head injury in the past, it is advisable such person visits an eye doctor for a comprehensive eye examination.
Early diagnosis and proper treatment of Crossed eyes have promised to give children and adults affected the ability to continue to have a healthy eye and vision development.