- Astigmatism - lenses, glasses or surgery?
- Vision correction
Astigmatism - is a common and easily treatable disorders caused clouding visible objects. Astigmatism occurs when the cornea or lens of the eye are the wrong bend. Typically, people with this disorder of the cornea has a more flat areas and areas with strong bending. This leads to the fact that a person sees the objects washed matter how far away they are. Along with the haze visible objects for astigmatism can be characterized by frequent headaches and eye strain.
Adopted The beaten corneal astigmatism and lenticular - improper curvature of the cornea and lens, respectively. Astigmatism often develops in combination with nearsightedness or farsightedness. Astigmatism may be present at birth or may develop as a result of eye injury, illness, or surgery. The causes of this disorder are not reading in poor light, the habit of sitting too close to the TV, or long-term work at the computer.
Astigmatism is very common, but a small degree of its influence on visual acuity. The high degree of astigmatism may have a significant impact on the function of so astigmatism should be promptly evaluated and treated. It lends itself well to correct congenital form of astigmatism. It is much harder to deal with acquired astigmatism arising after various injuries and illnesses.
What is astigmatism eyes and see how people with astigmatism
Astigmatism - a visual impairment associated with the lack of a clear focus image of an object on the retina. This happens because of a violation of the cornea or (much less likely) lens. Thus, the isolated corneal and lenticular astigmatism.
Normally, the cornea is the transparent section of the world. Rays are refracted in a cornea are focused in one point of the retina, resulting in a clearer image of the subject. When corneal astigmatism cornea has an irregular shape or a segment of a rotating ellipse (correct astigmatism), or covered with scars, opaque patches (irregular astigmatism). This creates a little (sometimes a lot) meridian refraction of light rays, which contributes to the appearance of several points on the retina image and leads to lack of clarity of vision objects. The combination in one eye corneal and lenticular astigmatism. A person with astigmatism sees all things vague and the degree of visual impairment has a clear connection with the degree of astigmatism.
A small degree of astigmatism (no more than 0, 5 diopters or D - a unit measuring the optical power of the lens; 1 D is equal to the optical power of the lens with a focal length of 1 meter) - a phenomenon very often, his men usually do not notice, because the visual acuity it does not It reflected (physiological astigmatism).
The degree of astigmatism can be much larger, there are three degrees of it:
- weak degree of astigmatism - no more than no more than 3.0 D;
- the average degree of astigmatism - from 3.0 to 5.0 D;
- astigmatism high - more than 6.0 D.
What causes astigmatism
In most cases astigmatism is hereditary - there are entire families, the sick astigmatism. Congenital astigmatism is usually correct. It meets and acquired astigmatism, it develops after injuries and diseases - various infections, metabolic diseases of the cornea or lens. At the same time on the surface of the cornea and lens appear cloudy spots on the surface of the cornea - scarring, resulting in impaired vision and. There is such a thing as post-operative astigmatism - it develops after a variety of eye surgeries. For example, astigmatism is a typical complication after cataract surgery
Cataract surgery - surgery
As in the operation for obtaining access to the lens is carried cut on the edge of the cornea.
Astigmatism is an eye - is not fully understood disease. Causes of astigmatism to date have not been established, but their study is underway.
Types of astigmatism
At least with the right eye astigmatism are two so-called principal meridian always perpendicular to each other - vertical and horizontal. One of them always has a higher refractive power, and the other smaller. In most cases, strongly refracts the vertical meridian, at least - horizontal. On this basis astigmatism divided into forward and reverse.
Direct astigmatism - this is when a stronger refraction has a vertical meridian, reverse astigmatism - the prevalence of refractive horizontal meridian. If the principal meridians are oblique direction (however, remaining perpendicular to each other), it turns astigmatism with oblique axes.
Depending on the combination of refraction (refractive power of the eye) in the principal meridians are several types of astigmatism:
- when emmetropia (normal refraction) in one of the main meridians and myopia or hyperopia (farsightedness or nearsightedness), astigmatism in the other meridian is called simple; There are simple myopic astigmatism and hyperopic astigmatism simple;
- if both main meridians has hyperopia or myopia of various degrees, it is difficult astigmatism; distinguish complex myopic astigmatism
Myopic astigmatism - a combination of astigmatism and nearsightedness
hyperopic astigmatism and complex;
- if one of the principal meridians attaching hyperopia, myopia and in another, it is mixed astigmatism
Mixed astigmatism - a violation of
During diagnosis astigmatism using a device known as a keratometer, determine the amount and direction of light reflected by the cornea. Furthermore, using keratoscopy determine the degree of curvature of the corneal surface.
Check astigmatism begins with visual acuity. Another method of diagnosis of astigmatism is the shadow sample - skiascopy. With this method it is possible to identify the position of the main meridians and determine their refraction.
By means of special devices Oftalmometres can quickly and accurately identify the corneal astigmatism, its nature, extent and location of the main meridians. Position the main meridians, the type and degree of astigmatism in this study are recorded in a cruciform shape, corresponding to the main meridians, numerals degree of astigmatism (in diopters) indicated graphically on a stronger meridian that gives an indication of the nature of astigmatism (forward or reverse). Work is also ultrasound of the eye.
To determine the degree of corneal astigmatism conduct computer corneal topography.
Additionally, with the help of corrective glasses or skiascope determined by the refraction of each of the main meridians.
See also the fundus to exclude pathology of the vitreous body, nerves and blood vessels located in the area of the fundus.
For the correction of astigmatism with the patient may be advised to wearing glasses or contact lenses.
There are special glasses and lenses, which help not only with myopia and hyperopia, and astigmatism at. There are many types of contact lenses, which are suitable for patients with different needs. Your doctor will help you choose the most suitable option.
For the treatment of astigmatism
Treatment of astigmatism - conservative or surgical?
It may also be used surgical techniques. The most common of these is the laser vision correction. The operation is performed under local anesthesia, it takes no more than half an hour, and the patient may be on the same day to go home.
An alternative to laser vision correction are photorefractive keratectomy and laser subepithelial kerateektomiya. The latter is ideal for people who have thin corneas from nature, as well as those who due to work or contact sports increased risk of eye injury.
Side effects of such operations can be dryness and irritation of the eyes, deterioration and even loss of vision. However, this rarely occurs and in most cases the operation is successful.
Exercising with astigmatism
When astigmatism is useful as a general gymnastics and special exercises for eyes, which should be carried out every day two or three times a day for a month and then take a break and subsequent courses of conduct prescribed by a doctor:
- sit on a chair, back straight, head up; look down and to the right, keeping in view long as possible; then transfer the look to the right and repeat the exercise;
- former starting position; Look at the tip of the nose and eyes get tired when making their rotational movement in one or the other way;
- former starting position; close your eyes and hands to massage them first, and then the fingertips to the center first and then him.
Glasses with astigmatism
Selection of glasses with astigmatism - a difficult task. At correct congenital astigmatism, visual acuity can be significantly improved, or even brought to normal with the help of corrective glasses cylinder - cylinder segments optically not the action against the Rays, going to the plane of the cylinder axis. This window should be as activity in relation to the rays, going in the direction perpendicular to the axis.
Collective or cylindrical glass diffuser respective forces pose an astigmatic eye so that the axis of the cylinder located on the meridian, which is the least deviation from the norm and refraction is no need to change.
To prevent astigmatism should promptly treat all eye diseases - it will prevent the acquired astigmatism. When mild astigmatism in order to avoid the progression of the disease, should be dosed visual load (in any case can not be read, or lying in low light), to carry out exercises for the eyes, the courses of physiotherapy. To view the training there are also special pinhole glasses.