Astigmatism is a defect in the organs of vision, the cause of which is a violation of the correct form of the refractive eye system: the cornea, the eyeball or the lens. As a result, on the retina, each point of the projected object looks like a blurred spot. Accordingly, a person with astigmatism perceives objects as distorted and fuzzy. If the correct shape of the human eye is broken, the meridians of organs of a spherical shape (cornea, eyeball or lens) are perpendicular to each other. Refraction of the light beam in one of them will be stronger, and in the other - weaker.
- 1Definition of disease
- 4Possible complications
Definition of disease
Such a violation of normal visual perception can be either a separate problem or a combination of astigmatism with myopia (myopic astigmatism) or with hyperopia (hypermetropic astigmatism).
If the patient has hypermetropic astigmatism, the light beam "leaves" beyond the retina. This kind of astigmatism has a simple or complex form.
There are three types of "long-sighted" astigmatism:
- Simple hypermetropic(H) combines long-sightedness in one meridian with normal refraction in the other;
- Complicated hypermetropic(LV) combines different degrees of farsightedness in the meridians;
- Mixed(MH or NM) - farsightedness in one meridian in combination with myopia in another.
In the presence of complex "long-sighted" astigmatism, a strong distortion of the visible image of objects is most often observed in connection with a high violation of the refraction of light rays. Doctors call three degrees, which are determined depending on the distance of two focuses from each other:
- Lightweight(up to 2 diopters);
- Average(2-3 diopters);
- High(above 4 diopters).
The degree of pathology is of great importance in the complex hypermetropic type of the disease.
Deformation of the surface of the cornea or lens, which leads to visual impairment, in 98% of cases is congenital.By inheritance, astigmatism can be transmitted even after a generation, and at the same time not only from direct relatives. Congenital astigmatism sometimes passes independently during the first five years of a child's life.
Acquired astigmatism is less common.Pathological changes can cause such causes as eye trauma, the consequences of ophthalmic operations, eye diseases, including those caused by various types of infections.
Pathology can occur in an infant, if the mother during the period of pregnancy suffered an infectious disease.
Acquired astigmatism is due to the presence of scar changes on the cornea, caused by these factors.
Minor "irregularities" in the shape of the refractive parts of the eye can not create appreciable inconveniences. In the case of serious disorders or progression of the disease, the following symptoms of "long-sighted" astigmatism manifest themselves:
- Blurred vision. Visible objects can be perceived as "blurred" or distorted;
- Rapid eye fatigue;
- Periodic headache, especially with intense visual stress;
- Feeling of "burning" in the eyes.
The observed objects seem to be "bifurcated".
In addition to a certain discomfort caused by distortion of visible objects, "long-sighted" astigmatism, especially hereditary, can cause a number of more serious consequences.A child who has seen incorrectly from the first years of life can develop strabismus. Another "formidable" ailment arising from astigmatism is amblyopia. This progressive lowering of vision develops due to the fact that there is a functional disorder of the visual analyzer. The brain can not continue to handle signals coming from the eye normally. This decrease in vision is not amenable to correction with the help of glasses.
In childhood, the manifestation of astigmatism is fraught with a violation of the motor and cognitive development of the child.
There are no ways to get rid of hypermetropic astigmatism with the help of medications.
Correct the vision for this disease can be, by selecting suitable for the patient glasses or contact lenses.Appointment and selection of glasses (lenses) is strictly individual.
To treat farsighted astigmatism is possible only by methods developed by modern ophthalmic surgery.Ignore the manifestations of this disease in any case impossible.This leads to the development of strabismus and a sharp deterioration in the ability to see.
If astigmatism is congenital, the consequence of a visual defect may be a violation of the child's development.
Astigmatism is corrected by cylindrical lenses, which must have different degrees of curvature horizontally and vertically. Cylindrical glasses lenses can be combined with lenses for correction of hyperopia. However, in the case of the development of a high degree of astigmatism, the patient begins to feel dizzy, and the eyes also ache. In the presence of "long-sighted" astigmatism, it is necessary to use special spherocylindrical lenses.
After the patient has been assigned glasses, he needs constant supervision with an ophthalmologist. This will allow timely correction of the patient's condition, replacing lenses or glasses for stronger or weaker ones.
Cure astigmatism will help only surgical intervention. There are the following types of operations that relieve this disease:
- Keratotomy, in which a number of blind incisions are applied to the cornea. This helps to make refraction of light on the strengthened axis weaker. Keratotomy is used in cases of mixed or "short-sighted" astigmatism;
- Thermokerukoagulation: cauterization of the peripheral zone of the cornea with a metal needle. This increases the curvature of the cornea and the strength of the refraction of light. This way you can correct "long-sighted" astigmatism;
- Laser coagulation:cauterization is performed using a laser beam;
- Laser keratomilez.In this case, an excimer laser is used which evaporates from the surface of the cornea a layer of the required thickness.
Surgical intervention is carried out in those cases if there are no contraindications: scars on the surface of the eyeball, retinal pathology, and some other diseases.
Prevention of astigmatism:
- Correct distribution of daily loads on visual organs;
- Alternating periods of eye strain with physical activity and exercises designed to strengthen vision;
- Prevention of traumatic effects on the organs of vision;
- Prevention of diseases caused by inflammation of the cornea;
- Regular preventive examinations at the ophthalmologist.This is necessary in order to timely identify the initial signs of astigmatism.
- To prevent occurrence of secondary complications of hypermetropic astigmatism it is possible, if in time and effectively to correct defects of visual perception caused by this illness.
The human vision is a complex system that includes both the work of the central nervous system and a number of organs that capture and refract light.Even a slight "irregularity" of the surface of the spherical shape of the parts of the eye can lead to an inaccurate focusing of the image on the retina. Specialists say that most people have an insignificant degree of astigmatism that does not affect visual acuity. However, with more serious defects, astigmatism needs correction or treatment.
Correction of the disease with the help of glasses or lenses, which are selected individually.Especially complicating the process of selection in those cases when astigmatism is combined with farsightedness. In this case, spherical cylindrical lenses are used.
The test for astigmatism can be passed here.