Strabismus and Amblyopia : reason for their occurrence
Because we have two eyes, it is obvious that in the course of the two images must be formed.To both of these images merged into one in the brain, it is necessary that cooperation between the two organs of vision was perfectly harmonious.When placing any object remote two optic axes must be parallel, and when viewed on any object with a smaller distance than infinity (in practice, this means a distance of less than 20 feet), they must intersect at one and the same degree.
absence of such a harmony of action known as strabismus, or crossed eyes.Strabismus is one of the defects of the eye, causing the greatest suffering is not only due to the decrease of view, but also because of the lack of symmetry in the most expressive part of the face that leaves a bad mark on a person's appearance.This state-one of those that baffled ophthalmological science for a long time.Despite the fact that the theory of its origin as described in textbooks seem suitable for a number of cases, the other cases they are left witho
idea that the lack of harmony in the movement of the eye associated with a corresponding lack of harmony in the power of the muscles, turning them into the sockets, it seems so natural that at the same time, this theory has been widely recognized.Operations based on it, were at that time very fashionable, but now most experts recommend them only as a last resort.However, to many people it has helped, but even in the best case, this way the correction of strabismus is very rough, and the state has even deteriorated in many cases.At the same time hope for the restoration of binocular vision - the ability to merge the two visual images into one - is hardly necessary.
Muscle theory really so bad picked confirm to myself that when I suggested that strabismus is a condition caused by refractive anomalies (hyperopia was considered responsible for the production of convergent strabismus, and myopia of the production of divergent strabismus), this theory took everywhere.But she was too poor, and now medical opinions were divided between the different theories.One theory attributes it to state, in most cases the defect is not muscle, and nerve supply, and she won a lot of supporters.Another theory focuses on the lack of ability of the so-called fusion, and recommends that you use it for the development of prisms or other measures.A third theory states that the anomaly of the eye is the result of irregular shape and eye socket, because it is impossible to change this state, to protect the operation as a means of neutralizing its effects.
To each of these theories to make consistent, you need to get rid of superficial explanations on a variety of unpleasant facts.Uncertainty of results of operations on the eye muscles is sufficient to cast a shadow of suspicion on the theory linking squint with any abnormality of muscle.At the same time there was a significant number of cases of paralysis of one or more muscles without the appearance of a squint.Moreover, the weakening of paralysis could not weaken strabismus, as well as reduction of strabismus not weaken Palsy.One well-known ophthalmologist, met with so many case histories where training designed to occur be- tween the development of skills, did not bring any benefit, that in such cases he was to recommend surgery on the muscles.Another ophthalmologist, drawing attention to the fact that most gipermetropikov not decimated, was forced to admit that hyperopia is not without the help of any contributing circumstances strabismus.
That condition of not playing a significant role in the appearance of strabismus, confirmed by many facts.Indeed, strabismus is usually accompanied by refractive errors, but in some people squint there is only a very small error of refraction.It is also true that many people from convergent squint is hyperopia.However, many other people with strabismus hyperopia not observed.Some people with convergent strabismus is myopia.A person may also be convergent squint with one normal eye, and the other - hypermetropic, myopic or blind.
Usually vision eyes turned inward, lower than eye sight, which looks directly.However, there are cases where the visually impaired eyes looking straight, and the eyes with the best vision is turned inward.If both eyes are blind person, it may be that both of them will look right or the one directly and the other inside.With one good and the other two blind eyes can look straight.As a rule, the more blind eyes, the more pronounced squint.Often, however, there are exceptions, and in rare cases, an eye with normal vision can almost hard to look inside.
addition, strabismus can disappear and reappear.Maybe so that esotropia is converted to divergent and back again in convergent.At the same refractive error, one person would squint, and the other not.The third will not mow the eye, the other.The fourth will first mow one eye and then the other.In the fifth case, the degree of strabismus will change.One will be fine without glasses or other types of treatment, and the other - in their application.The cure can be permanent or temporary, and relapse can occur both when wearing glasses or without them.
Whatever ignored refraction, eye squinting eyes still worse of eyes looking straight ahead.In the eyes of the device is typically not found any express or sufficient reasons for this.Opinions of researchers differ as to whether a violation of a curious result of strabismus or squint itself is its result.However, the prevailing opinion is that it is, at least, is exacerbated by the presence of strabismus, which is reflected in the title given to this state of amblyopia ex anopsia, which literally means "the weakening of vision due to disuse."Ambiopiyu usually associated with the need to suppress the image given by a deviating eye, to avoid irritation of the double image.However, there are a lot of eyes that are mowed, but without any manifestations of amblyopia.In turn, amblyopia is detected in the eyes that never mowed.
literature on the issue under investigation is full of despair about the possibility of treatment of amblyopia.In the popular press of people concerned about the health of children, convinced that if a child has strabismus, treatment should begin immediately so as not to lose the vision of the squinting eye.According to a well-known ophthalmologist, after the child reaches six years is usually little that can be done to improve the amblyopic eye view.At the same time, another ophthalmologist says that "the function of the retina never again returns to normal, even if the cause of visual impairment."It is well known also that if at some point in the life of a good eye sight is lost, then the vision amblyopic eye often becomes normal.Moreover, an eye at one time can be ambliopiche-sky, and in the other - be they stop.If you cover up something good eye, squinting eye may be amblyopic so that it is hardly able to distinguish light from darkness.But if you open both eyes, the vision of the squinting eye can be found just as good, if not better, as the vision of the beholder right eye.amblyopia, a transition from one eye in many cases to another.
double vision in strabismus is very rare.If it does occur, it often takes strange forms.When the eyes are turned inward, the image seen by the right eye, must, according to the laws of optics, have the right and the image seen by the left eye-left.When the eyes are turned out, the opposite pattern is observed.But often the situation is reversed images of the right eye image with esotropia will be seen on the left, and the image of the left eye-right, whereas in divergent strabismus we find the opposite case.This condition is known as "paradoxical diplopia" Moreover, people with an almost normal vision with both eyes, clearly staring directly can have both types of ghosting.
All proposed the theory failed in an attempt to explain the above facts, but it is known that in all cases of strabismus can be noticed the presence of voltage, and the fact that, following the disappearance of strabismus, as well as the disappearance of amblyopia and refractive errors,should stress reduction.We also know that all people with normal eyes can create a state of strabismus by applying force to see.This is not such a difficult thing, and many of the children have fun in this occupation, it gives adults unnecessary anxiety for fear of a possible conversion of a temporary into a permanent squint.
Make esotropia is relatively easy.Children usually do this by trying to see the tip of his nose.Production of exotropia is more difficult, but with practice, people with normal eyes at will be able to turn out any eye or both.They can also learn one eye rotate upwards and the other downwards, or one up and the other outside the desired angle.Indeed, using the appropriate type of stress can optionally produce almost any form of strabismus.When it made arbitrary (voluntary) strabismus, usually a deterioration of vision, and conventional methods of measuring muscle strength, likely to be registered with the nature of strabismus muscle deficiencies.