What is astigmatism?

astigmatism is a condition of an eye that causes either blurred vision, or the feeling that each eye sees objects slightly differently. The structural problem - usually either of an unevenly curved cornea or lens - causes light to come into the eye so that it does not focus properly. This disorder is quite common and affects about 30% of people to some extent. Treatment is not always necessary, but if the problem is severe, lenses or surgery can help improve the vision of a person.

anatomy

The human eye is usually a perfectly round ball. The light that comes into the eye is focused on the cornea and the lens to the retina point where the image is detected and the brain is communicated. Some of the cornea or lens are not perfectly round for some astigmatism; It is often shaped more like football. When the eye is not curved correctly, the light that comes into the eye

astigmatism is a type of refractive error, which means that the eye does not bend the light coming into it to focus on the right place on the retina. About myopia (myopicity) andFrequentness (hyperopia) is also refractive errors caused by too curved or too flat cornea. The eyes of people who are short -sighted, focus the image in front of the retina, while in those who are far beyond. People may have both astigmatism and another refractive mistake; It is estimated that about 2/3 people who are short -sighted have another condition.

types

There are different types of astigmatism, depending on which part of the eye is irregularly shaped, where the light is concentrated and whether the main meridians are perpendicular. This condition may be caused by a defect either in the cornea or lens, although the type of cornea is multiple.

Normal eye focuses the image to one point; Optometry draws an imaginary plus-underwriting (+) in the middle of the pupil, where this point should be focused. These are referred to as vertical and horizontal or main meridians. In some astigmatism, both meridians do not focus at the same point. If one focuses on the retina while the other does not, is known as simple , while if both of them focus at the front or behind the retina, it is known as merged . One point in front and one is called mixed .

As with myopia and foresight, the focus in front of the retina is called myopic and for hyperopic . So if one meridian focused in front of the retina, while the other is on it, it would be called simple myopic astigmatism .

When the main meridian perpendicularly perpendicular - which means they meet at 90 ° Anglue - is known as "regular" astigmatism. If the angle is turned off, it is called "irregular" and is a little more difficult to heal. The irregular type is often caused by an eye injury or a disease called keratoconus, in which the cornea receives the shape of the cone.

Symptoms

minor astigmatisms often largely unnoticed to a large extent, but serious cases may be seen in addition to blurredIt causes headaches, squinting and tired eyes. Most people with corneal irregularities are born with them, but they don't have to notice any problem until they get rid of. Even those who have few symptoms can be diagnosed with this condition during the routine eye test. Since many signs are obviously or directly related to the vision, people can find that treatment improves headaches they don't even realize about.

detection

There are several ophthalmological tests to determine the presence and level of astigmatism. Keratometer and topographer of the cornea are tools to use the corneal curvature. The authorfractor can provide an estimate of the eye ability to concentrate the light properly. These tools are non -invasive and most ophthalmologists and optometry are able to detect even slight curvature problems during a simple eye test.

Sometimes astigmatism can be detected at home by covering one eye to look at the object and then change to cover the other OKo. Switching back and forth when looking at one object or in one direction, a person may notice that the object seems to move as if each eye sees it in a slightly different place. This usually indicates the presence of corneal curvature.

Treatment

Goggles or contact lenses can be prescribed treatment most forms of astigmatism, but generally do not complicate the condition. Two different lenses often help to concentrate together, compensating for uneven focus. Glasses cannot be used to treat PEOS in an irregular form, although some types of contact lenses can usually help. One type of contact lens actually helps to transform the eye; This treatment is called orthokeratology or ortho-k.

Surgical correction is an option for serious cases. To transform the cornea of ​​the eye and make it a more spherical number of different procedures. Laser Laser Surgery In situ Keratomileusis (lasik) Laser uses laser to cut the underside of the cornea after lifting the top. Photo -characterAsstomy (PRK) and a similar technique called laser assisted by sub -elegial keratomileusis (lasek) removes or folds back the outer layer of the cornea and transforms the upper surface. An optometrist can help the patient decide which method is a better choice if surgery is recommended.