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Strabismus (strabismus) in children and adults: cause and treatment
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Strabismus is a deviation of the position of the eyes in which the eyes are not aligned correctly and are not focused on the same point. In the absence of alignment, the eyes see incompatible images and confusing double vision results.
Strabismus types
- esotropia (convergent strabismus) if one eye turns inwards
- exotropia (divergent strabismus) if one eye turns outward
- hypertropia or high position of one eye
- hypotropia or low position of one eye
If the strabismus develops at a young age and cannot be remedied quickly, the brain learns to neurologically suppress one of the two images. Then you can only look with one eye. It can also happen that one alternates between both eyes and sometimes looks with one eye and then again with the other. In that case, however, one still never looks with both eyes at the same time.
Read also: Testimony: strabismus
Link strabismus and lazy eye
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The suppression or suppression of one of the two eye images leads to amblyopia or lazy eye. Amblyopia means that the brain does not properly process visual information from one eye and several neurovisual skills become underdeveloped. These include visual acuity, depth perception (stereo vision), motion perception, eye cooperation, eye-hand-body coordination and the fluency with which visually controlled movements can be performed.
Early screening and possible treatment of strabismus and lazy eye are absolutely crucial to optimize visual brain development and to minimize permanent damage, or at least developmental delay. If strabismus develops later in life (older child or adult), it will be more difficult, if not impossible, to develop suppression as an adjustment mechanism. The double vision can therefore be more disturbing. But because the brain has developed visually normally up to a certain age, the rehabilitation of previously acquired and practiced visual skills will also normally proceed more quickly.
In both cases, visual therapy, or secondarily eye muscle surgery, should attempt to restore eye alignment, neurological fusion of both eye images, and depth perception. Strabismus and lazy eye often have an underestimated but far-reaching impact on visual functionality. Restoring binocular vision is important for reading and learning skills, motor skills, mobility, (later) career opportunities and mental well-being. Research over the last two decades has shown that the neurological core of lazy eye and strabismus is much more treatable than previously believed. In the vast majority of cases, the patient’s eyes, eye muscles, and brain are physiologically healthy, but the brain must learn to correctly use and integrate the eyes, eye muscles, and visual information flows (again).
Read also: Lazy eye (Amblyopia): ‘In practice often a poor treatment’
Strabismus causes
Strabismus occurs in 3 to 5% of the population. It can be a congenital defect, occur in childhood, or in some cases even emerge in adults.
Strabismus in babies
In newborns it is sometimes a pseudostrabismus or a false form of strabismus. In fact, aligning the eyes is a skill learned during the first months of life. During the first six months of life, approximately half of all children have their eyes crossed from time to time. That is normal. Babies also often have a wide nose bridge, which makes it seem as if the eyes turn inward. Nevertheless, as a parent you can keep an eye on the evolution of the eye position. If you are concerned, you can have a refractive examination carried out at the ophthalmologist from six months onwards to identify risk factors. Even if there is a family history of strabismus, that is not a bad idea. However, if the strabismus is present continuously from birth, early examination and appropriate treatment is necessary.
Strabismus in young children
Some children do not develop a strabismus until after 12 months of age or in toddler or preschool age. Possible causes are:
- An eye defect, as a result of which one eye sees less sharply or there is a large difference in sharpness between the two eyes (anisometropia).
- Long-sightedness, as a result of which the eyes have to make more effort to obtain a sharp image, can lead to the inward turning of one eye. This kind of strabismus is called accommodative strabismus.
- A less good control or coordination of the different eye muscles. This can happen if the neurovisual development process goes off track for some reason, possibly after going through a childhood illness or extreme fatigue.
- An accident or neurological abnormalities can lead to a disturbed innervation of one or more eye muscles, resulting in partial ocular muscle paralysis.
- An accident with damage to the eye socket can be the cause of strabismus.
Strabismus in adults
In adults, multiple causes of strabismus are also possible:
- Strabismus that has or has not been treated in childhood can sometimes (again) worsen in adults. This is called decompensation of the strabismus. Decompensation often occurs in the thirties or forties in someone who has never really been thoroughly visually rehabilitated or who had eye muscle surgery as a child. Eye muscle operations often only treat the strabismus cosmetically. However, the brain has not learned to use the eyes correctly and to integrate neurologically. That is why that apparent straight eye position will often calve back over time. Decompensating for strabismus is also often accompanied by disturbing symptoms such as headaches, tired eyes, light sensitivity and possibly double vision.
- A visually impaired eye as a result of an accident or other eye injury can also be the cause of an eye turning away in adulthood.
- Paralytic strabismus or strabismus due to eye muscle paralysis can occur after an accident, but also as a neurological symptom of other disorders (e.g. cerebral haemorrhage, MS, diabetes, oxygen deficiency due to vascular disease, …)
- Restrictive strabismus or strabismus due to mechanical limitations of the eye muscles usually occurs after an accident with damage to the eye socket or in patients with thyroid problems that lead to damage to the eye muscles.
Screening a diagnosis
If eye position problems are diagnosed from birth, it is important to monitor the child closely so that visual brain development can be optimally supported during those first crucial years of life.
At the age of one and two years, Kind & Gezin screens for the most egregious risk factors that can cause strabismus and lazy eye. It is very important to provide a child with appropriate glasses even at that young age if necessary. This can prevent the development of eye cooperation problems and lazy eye in toddler or preschool age.
In addition to a derailed visual development process, strabismus can also be the result of an underlying (neurological) disease. It is therefore very important to exclude other possible pathologies with a comprehensive neurovisual examination.
Read also: How do the hearing test and eye test work at Kind en Gezin?
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For a long time it was thought that there was a critical period (for example up to eight years) after which strabismus and lazy eye could no longer be treated and the brain “petrified”. Recent research on brain plasticity, and in particular the book ‘Learning to see depthby brain scientist Susan Barry, this appears not to be the case and strabismus and lazy eye are treatable to some extent for life. But because the brain is still developing at a young age and growing explosively, it is certainly better to try to normalize, or at least optimize, visual brain development as early as possible.
Also read: Strabismus (strabismus) should be treated as early as possible |
Therapy
With newborns, the situation is somewhat more complex. During the first 18 months, surgical realignment of the eyes and possibly the provision of appropriate baby glasses may encourage the brain to spontaneously return to seeing with two eyes and to develop normally. That possibility should be explored and weighed against any potential drawbacks (such as muscle damage) that surgery may entail. For a more detailed discussion of these advantages and disadvantages, the book ‘First Aid for Strabismus and Lazy Eye: An Orientation Guide for Parents and Patients‘ hit it.
Read also: Visual therapy and eye muscle surgery for strabismus and lazy eye
Sources:
www.scheelzien.org
