People with crooked eyes see normally
When squinting (strabismus) the two axes of vision deviate from each other as soon as one focuses on an object. In children, this can have a decisive influence on brain maturation and thus severely limit the ability to see for life. Strabismus can have different causes and therefore often requires individual therapy. Read more about strabismus here.
The baby should be examined by the ophthalmologist for the first time from the age of 6 months so that poor eyesight, so-called amblyopia, can be detected early.
Usually you always move both eyes together in the same direction. This ensures that a three-dimensional image is created in the brain. However, this balance can be disturbed, so that the visual axes deviate from one another, although the focus is actually on something specific. Then one speaks of strabismus, colloquially strabismus.
A manifest strabismus (heterotropia) is when the squint persists. At the latent strabismus (heterophoria) on the other hand, the person concerned only squints at times. In both cases, different squint directions are possible. In addition, you can look at the squint according to its origin in Accompanying strabismus and Paralytic squint organize.
Manifest squint (heterotropia)
Depending on how the visual axis is shifted, a distinction is made:
- Convergent strabismus (esotropia): manifest inward squint (internal squint) - the visual axis of the cross-eyed eye deviates inward.
- Divergent strabismus (exotropia): manifest outward squint (external squint) - the visual axis of the crossed eye deviates outward.
- Strabismus verticalis: manifest vertical squint - the visual axis of the crossed eye deviates upwards or downwards. Accordingly, a distinction is made between different variants such as Hypertropia (manifest higher position of an eye) and hypotropia (manifest lower position of an eye).
- Cyclotropy: manifest curling squint - the cross-eyed eye "rolls" inwards (incyclotropia) or outwards (excyclotropia) around the visual axis.
Latent squint (heterophoria)
Latent squint occurs, for example, when the person is tired or when one eye is covered. Analogous to manifest strabismus, a distinction is also made here between the above-mentioned squint directions: latent outward (Exophoria) or inward squint (Esophoria), latent superiority (Hyperphoria) or lower eye (Hypophoria) and latent curl squint (Cyclophoria).
Read more about the symptoms and treatment of latent strabismus in the article Heterophoria.
With accompanying strabismus, too Strabismus concomitans called, the squint angle remains constant with all eye movements, that is, one eye “accompanies” the other. Spatial vision is not possible, the visual acuity of the cross-eyed eye is usually weaker. Concomitant strabismus occurs in most cases in children.
There are different forms of concomitant strabismus. The most common is that Early childhood squint syndromethat occurs within the first six months of life - before a baby has learned to see with both eyes (binocular vision). It makes up the majority of manifest strabismus.
At the Normosensory late squint on the other hand, strabismus begins in children after the first year of life, and thus after training in binocular vision.
Another form of concomitant strabismus is that Microstrabismus. Here the squint angle is less than five percent, which is why the squint is often discovered late.
With paralysis squint, too Paralytic strabismus orStrabismus incomitans called, a muscle or a supplying nerve of the eye muscles fails. As a result, the eye can no longer move completely, resulting in a misalignment.
Unlike the accompanying strabismus, paralysis strabismus affects all age groups. It usually appears as a sudden strabismus with no warning signs. Typical features are double vision and an incorrect spatial assessment. If the head is held diagonally to the side, the squint can often be minimized, as the neck muscles bring the whole head into an oblique position so that the eye looks straight ahead, although it looks sideways out of the eye socket.
Squinting in children
Strabismus is particularly common in children: about six percent of all children in Central Europe have secondary strabismus (see below: Causes), in over half of all cases before they are three years old. Since the brain of children is still developing strongly, the brain recognizes the incorrect image information of the cross-eyed eye as incorrect and suppresses this information. As a result, the development of visual performance can be permanently damaged by the strabismus. This is why it is particularly important to treat strabismus in children early.
Strabismus in itself only describes two different lines of sight, so it is a symptom. Affected people can sometimes not see well in three dimensions or perceive double vision.
It is often not that easy to determine whether someone is really cross-eyed. A possible misinterpretation for strabismus in babies is based on the often deep-seated eyelids at the transition to the nose (epicanthus). They can give the wrong impression of deviating visual axes, even though the visual axes of both eyes are the same. This is particularly often the case with Asian babies. This phenomenon is also called pseudostrabism. It has no disease value because no squint angle can be measured.
If you lose sight in one eye, squinting outwards slowly occurs over several years. Some people only have an outward squint when they look into the distance. This is called intermittent squint.
Symptoms of paralysis strabismus
The squint angle depends on the direction of view. In some viewing directions, the paralysis strabismus is not noticeable, since usually only a specific muscle is affected by the underlying paralysis and not all eye muscles are always involved in all eye movements.
Patients with paralysis strabismus are usually already noticeable by a sloping head position, in which the affected muscle is relieved. You sometimes see double vision and feel the need to turn a blind eye or to turn a blind eye.
Strabismus: causes and risk factors
Squint can have many causes. If the squint occurs suddenly, nerve damage, infections, tumors or bleeding must be ruled out.
Causes of concomitant strabismus
Corneal injuries as Changes in the retina (Retina) can trigger concomitant strabismus. If you lose sight in one eye, squinting outwards slowly occurs over several years.
In the case of children, there must Ametropia excluded - for example with strabismus divergent, because this creates an outward squint. Also Birth defects as Disturbances in brain development can cause strabismus. Premature babies in particular are often affected by this: One in five children with a maximum birth weight of 1250g will squint later in life.
Accompanying strabismus is less common in adults. The possible causes are also more diverse here than in children - in the little ones, squinting can often be attributed to the same reasons, depending on age.
However, it is not always clear that there is only one cause of this type of strabismus: the eye muscles and the nerves involved are functioning, and the trigger must lie deeper in the brain than just a muscle failure. Even if the causes cannot ultimately be clarified, one usually suspects a deficit in the sensorimotor coupling of some muscles. This means that, for example, the sensors that are responsible for the position of the eye do not transmit completely correct information about the muscle position to the brain and this leads to a misalignment.
Causes of paralysis squint
The paralysis strabismus can already through a birth Brain trauma or one defective brain training arise. A paralysis of individual muscles is sometimes based on one Encephalitis (Encephalitis) or one infection during childhood. Measles viruses, for example, can penetrate into the brain and cause great damage here.
Also Strokes, Tumors as Blood clots can disrupt a nerve pathway and thus lead to sudden paralysis strabismus. Since the interconnection of the visual pathway is very complicated and the location of possible damage is diverse, detailed imaging (MRI) must often be used to clarify the cause of the strabismus.
Risk factors for strabismus
Refractive errors that are not treated, premature births and a lack of oxygen during childbirth can all lead to strabismus. If you go blind in one eye during your life, this eye no longer actively participates in the visual process, incorrect movements are no longer compensated, and within a few years the affected eye begins to squint.
In addition, there is a familial accumulation of strabismus diseases that suggest a genetic cause.
Strabismus: examinations and diagnosis
The right contact person on the subject of strabismus is initially the ophthalmologist. If necessary, he can call in a neurologist later.
In the first consultation, the medical history is recorded (anamnesis). The doctor can ask the following questions (for babies, the parents are asked):
- Which eye is affected?
- Is the same eye always affected?
- In which direction does the eye deviate?
- How big is the angle?
- Is the angle the same in all directions?
- Do you see double vision?
- Do you have other visual problems?
In some patients, the squint is clearly recognizable as such, in other cases it is not - for example because the squint angle is less than five degrees (microstrabismus). The same applies to the extremely rare curl squint, in which one eye is twisted clockwise or counterclockwise around the visual axis.
In general, strabismus can be recognized using the following methods:
During the masking test, the person concerned must fix the center of a table cross (Maddox cross) on the wall with both eyes. Then the ophthalmologist covers one eye and observes it. The cross-eyed eye reveals itself through an adjustment movement in the direction of the fixed point.
The ophthalmologist observes the light reflections of his visiting lamp on the pupils of the infant or toddler from a distance of 30 centimeters. If the reflexes are not in identical positions, there is a squint angle.
Read more about the examinations
Find out here which examinations can be useful for this disease:
Treatment of secondary strabismus
The accompanying strabismus is treated in several steps in small children. If there is an uncorrected visual defect (such as farsightedness), the child will get one glasses customized. In the case of unilateral visual impairment (e.g. lens opacification), one must accordingly use the Treat underlying disease. The ophthalmologist then observes for a few months whether the angle of the squint disappears.
If this is not the case, the eyes - starting with the weaker - must be alternately taped shut (Occlusion treatment). In this way, amblyopia (weak-sightedness) can be prevented or possibly suppressed. Because the brain is forced to use and train the weak eye despite strabismus. Occlusion treatment can take years - until the visual acuity of the weaker eye has improved sufficiently. The remaining squint angle can then be corrected surgically.
If the accompanying strabismus occurs after the age of six, the occlusal treatment is not required. Otherwise, children, adolescents and adults receive the same treatment as infants.
In some cases of concomitant strabismus surgery (Squint operation) necessary. Eye muscles that are too strong are loosened or muscles that are too weak are tightened. The most common form of secondary strabismus - the early childhood strabismus syndrome - is ideally operated on in healthy children between the ages of 5 and 6. The procedure is low-risk and has a good chance of success.
Treatment for paralysis strabismus
With paralysis squint you have to - as far as possible - die Treat the cause (for example the stroke). Sometimes a squint angle can also be achieved with a Prism glasses balance. But that is seldom the case. In some patients one comes Schiel Op into consideration.
Read more about the therapies
Read more about therapies that can help here:
Strabismus: course and prognosis
There is no general prognosis for strabismus. If someone squints because of unilateral vision loss, it will not improve on its own. Strabismus, which occurs as a result of ametropia, is different: if the ametropia is treated quickly, the strabismus can develop within a few months or a few years.
The course of strabismus is therefore strongly dependent on the cause. The better the trigger is to be treated, the better the prognosis. On the other hand, the later and more suddenly in life the strabismus occurs, the more difficult it is to treat. A prognosis must therefore be made individually by the attending physician. Often, an interdisciplinary approach with neurologists, ophthalmologists, paediatricians, radiologists and internists is required to address all the causes of the Strabismus to be able to cover.
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