WHAT IS STRABISMUS?
Strabismus is a deviation in the position of the eyes so that the eyes are directed to different points. Although it is a common condition that affects four percent of the child population, may appear later in adulthood. The deviation can be permanent and always noticeable, or may come and go, sometimes seeming Normal and abnormal other. One eye can be looking straight ahead while the other eye is deviated inward, out, up or down. In other cases, the eye may be right in some cases, and in others the dominant eye may deviate.
There are six muscles attached to the eyeball that control movement of the eyes. In each eye, two muscles move the eye right or left, the other four muscles move the eye up and down and tilt control the rotation of the eyes or dragging as if it were a horse flanges. When both eyes are aligned and focusing an object of fixation, all the muscles in each eye must be balanced and working together in parallel. When the muscles do not work together and balanced misalignment occurs that generates strabismus.
The eyes are designed to clearly focus images on the retina and then send the generated signal to the brain. If both eyes are aligned on the same target, the portion of the brain responsible for vision can merge the two images into a single image and three-dimensional. This creates depth perception and binocular vision, which stimulate the eyes to work together and maintain an "image" in the brain. When one eye turns as strabismus, two different images are sent to the brain. If the child is young, the brain learns to ignore the image from the turned eye, it vanishes, and can see only the image of the eye alignment or the better eye, ie the brain adapts to your situation. This causes a loss of depth perception.
Adults who develop strabismus, for example following trauma, have double vision (diplopia) because his brain is not trained for this, and knows not ignore or delete the image from the weaker eye or diverted.
The normal alignment of both eyes during childhood allows the development of good vision in each eye. Abnormal alignment of the eyes, as in the case of strabismus, may be the cause of a reduction in the level of vision or amblyopia (lazy eye). Amblyopia occurs in about half of children with strabismus. The brain recognizes the sharpest picture and ignore the worst image quality generated by the weaker eye or amblyopia. Amblyopia can often be treated by occlusion of the dominant eye, for the benefit of the weaker eye vision. If amblyopia is detected during the first years of life, treatment is usually successful. If the required treatment is not applied at the right time, amblyopia or decreased vision or permanent result generally more difficult to resolve. Generally, the faster are started on therapy for amblyopia, more likely to restore vision (SEE AMBLYOPIA)
CAUSES AND SYMPTOMS
Strabismus is caused by muscle imbalance. Still, the exact reason that causes an imbalance of strabismus is not understandable in all cases. It is known that strabismus can be hereditary and occur more frequently in a given family. This condition occurs equally in men and women.
The brain controls the eye muscles. This explains why children with cerebral palsy, Down syndrome, hydrocephalus or neurological disorders often suffer from strabismus. Moreover, if the sight of one eye is blurred because of a cataract or injury, then the eye will tend to deviate because otherwise it looks good incentive to lose line of sight.
The first symptom or sign that can be seen is that the eye is not straight. Sometimes young people close one eye to the brightness of sunlight and this may indicate a lack or poor depth perception. Some children seek money or nods to compensate strabismus and get a position in which the eyes are working together and aligned, this is called "torticollis".
Parents often have the false impression that children may aggravate or exacerbate the problem, but while it is true that fatigue, tiredness or stress can transiently worsen strabismus, strabismus aggravate children at will. Once suspected of possible diversion of an eye, you need a precise examination by the ophthalmologist to determine the cause and begin treatment.
DETECTION AND DIAGNOSIS
A child may be examined by the pediatrician, ophthalmologist, or optometrist during childhood, in order to assess the real potential of the problem, especially if associated strabismus or amblyopia. Parents often can not detect strabismus without the help of an ophthalmologist, since it is often difficult to differentiate between two eyes that seem to be misaligned and a true strabismus. Normally young children have the broad base of the nose, leaving a surface skinfold simulating the eye tends to hide under it and giving the appearance of a squint. Only the ophthalmologist is able to differentiate and distinguish physiological situation of a true strabismus.
Although there is no uniform idea about the age at which children should be examined for the first time, it is recommended that any suspicion of impaired eyes, go to the ophthalmologist, particularly where existing family history. Otherwise, just start a first review after 3 years. Fortunately there are a variety of tests for infants and children. If visual inspection is delayed until the child enters school, it may be too late for proper treatment of strabismus or amblyopia. Occasionally, a deviation of the eyes can be caused by a cataract or tumor within the eye. It is therefore important to recognize early.
The goals of treatment are to maintain visual acuity, align the eyes and restore binocular vision. Treatment of strabismus depends directly on the cause that provokes it, can be directed towards addressing muscle imbalance, the extraction of a cataract or other conditions that can cause an eye to turn. After a thorough examination, including an evaluation of the internal structures of the eye, the ophthalmologist should recommend optical treatment, appropriate medical or surgical. The dominant eye occlusion stimulates amblyopic eye and use it may be necessary to restore vision.
The two most common types of strabismus are esotropia (when the eye is deflected toward the nose), and exotropia (when the eye is deflected out.) Strabismus esotropia is more common in children. In these cases, children will not learn to read using both eyes together and may be affected eye vision weaker. In many cases, early surgery is needed to align the eyes and ensure the production of good binocular vision and preventing permanent vision loss in one eye on the child. The goal of surgery is to adjust the position and muscle tension in one or both eyes to align and regain the ability to focus on objects simultaneously.
Another common type of esotropia in children, after two years, is caused by the need for optical correction. These patients are farsighted and have the ability to force mechanisms to compensate for hyperopia approach, allowing them to see well at distance and near. The excessive exertion should be made to focus images, causes eyes were diverted to the nose. Wearing glasses is equal, decreases and balances the effort with their eyes, and disappears or partially corrected ocular deviation. Occasionally, drugs or special lenses called prisms, can be used to help properly targeted and in other cases, eye exercises (orthoptics and pleoptics) are needed to help children control their eyes.
An outward deflection or exotropia, is another most frequent types of strabismus. It usually occurs when the child is focusing on distant objects of vision and is often associated with myopia. Often intermittent exotropia, meaning only appears at certain times and especially when the child is tired, fatigued or ill. Parents may notice that the child winks by the brightness of sunlight. Although therapy or prismatic glasses tend to reduce the amount of deviation in some patients, surgery is usually required.
Strabismus surgery is usually a safe and effective treatment, but not a substitute for glasses or amblyopia therapy.
During surgery, a small incision that allows access to the muscles in order to modify their opposition and thus the traction forces exerted on the eyes. The muscle or muscles selection to be operated depends on the direction where the eye is diverted. Despite a thorough clinical evaluation and selection of the appropriate surgical technique, it is possible that after treatment are more aligned eyes but not perfect. In these cases, the fine and precise adjustment depends on the coordination between the eyes and its interpretation in the brain, which can be improved with vision therapy exercises. Some patients may need surgery after the use of corrective lenses or prisms.
It can operate one or both eyes at the same time. General anesthesia is required in the case of children, while in adults can be performed under local anesthesia. The recovery time is usually fast and can restore normal activity in a few days.
Early surgery is recommended in strabismus important because so children can develop normal vision, avoiding the appearance of amblyopia or other disorders. As the child grows, the chances of getting normal vision decrease. Moreover, the aesthetic factor of a wandering eye can have negative effects on self-esteem. As with any surgery, strabismus surgery also has some risks. Are minimal but consider infections, bleeding and other complications that can lead to a loss or decreased vision.
In recent years it is following surgery by injecting botulinum toxin to relax the muscle and allow better motility.
VISION LOSS CAN BE PREVENTED
Strabismus Treatment is most effective during childhood. Set binocular vision in an adult or adolescent is much harder though aesthetic alignment can be achieved at any age, differentiating between functional cure and cure aesthetics. If acquired awareness of the prevention of strabismus and alignment of the deviation of the eyes, amblyopia or vision loss can be prevented.
• Children with strabismus, not consciously cause of the deviation from worsening more ..
• Treatment of strabismus may be non-surgical and includes drugs, glasses or visual training.
• If surgical treatment is indicated, it is prudent to align the eyes when children are small, to allow the normal development of the mechanisms of vision in both eyes.