Hypermetropic astigmatism: causes, diagnosis and treatment
Mar 05, 2018
In a person with good vision, the surfaces of the cornea and lens have a regular spherical shape, so that the light rays passing through them are refracted in such a way that the image is focused exactly on the retina.With hypermetropic astigmatism , everything happens in a different way.
In patients with this kind of astigmatism due to curvatures of the cornea or lens, light rays are focused in several foci, one or all of them behind the retina.That is, people along with astigmatism have farsightedness.Table of contents: Causes Types of hypermetropic astigmatism Symptoms of hypermetropic astigmatism How to treat hypermetropic astigmatism
The reasons for the development of long-sighted astigmatism are not fully known.Physicians are inclined to assume that the disease is hereditary, although the influence of factors such as trauma to the eye, inflammatory processes of the eye, which cause the cornea to lose its sphericity, also plays a role.Less often the disease occurs due to the pathologies of the lens.
Types of hypermetropic astigmatism
Two types of long-sighted astigmatism stand out:
- Simple hypermetropic astigmatism, in which breaking of refraction of light rays occurs only in one of the main meridians.
- A complex hypermetropic astigmatism, in which in both meridians has a hyperopia of different sizes, and all the foci are located behind the retina.
Symptoms of hypermetropic astigmatism
Weak hypermetropic astigmatism often goes unnoticed by the patients themselves, especially if the patient is a child or a young person, because at a young age the vision organ can compensate for the problem due to the tension of the ciliary muscle.But an experienced doctor at an ophthalmological examination can always identify the disease, so you should regularly visit the ophthalmologist's office.
When the long-sighted astigmatism is expressed, the following symptoms appear:
- Visual impairment.Patients complain about the blurriness and doubling of objects, and what they see better in the distance is better.Voltage in the eyes during visual exertion.
In addition, the sign of hyperopic astigmatism can be even increased irritability or frequent changes of mood.
How to treat hypermetropic astigmatism
Correction of long-sighted astigmatism is performed using special spherical-cylindrical( collecting) lenses. Adults can write glasses with such lenses only for the performance of a certain job, children need to wear them all the time, because they often have serious complications of astigmatism: amblyopia, strabismus, astenopia.
In addition to glasses, correction of far-sighted astigmatism can be done with soft or hard contact lenses. In particular, this disease uses special toric lenses, which give a more effective correction of vision, when compared with glasses.
However, it should be noted that both glasses and lenses can only improve eyesight.Really, the problem can be corrected only with the help of surgical treatment, which, alas, is not carried out in childhood( usually up to 18 years).
To the methods of surgical treatment of long-sighted astigmatism include:
- Laser thermokeratoplasty.During this operation, the doctor acts on the laser on the peripheral zone of the cornea.At the points of such exposure, a burn occurs, due to which collagen fibers contract, and the peripheral parts of the cornea are tightened and flattened, and the central zone, on the contrary, protrudes - this is the shape of the cornea necessary for the normalization of vision.
- Thermoceratocoagulation, which also involves therapeutic damage to the cornea, but the procedure is not carried out with a laser, but with a miniature needle having a high temperature.
- Hypermetropic laser keratomileusis( LASIK or LASIK).This technique is particularly effective in farsighted astigmatism of medium and high severity.This surgical procedure cuts the cornea with a partial separation of its superficial flap and evaporation of the middle layer of the cornea in the peripheral areas.After the laser exposure, the flap is returned to its place.
The peculiarity of all these operations is that the main effect is on the peripheral optical zones of the cornea, and not on the central ones, as in myopic( nearsighted) astigmatism.
If there are contraindications, other surgical procedures may be performed to correct the astigmatism, for example, implantation of phakic lenses, keratoplasty and others.
In general, with timely access to a doctor with the help of the above methods of correction and treatment, you can completely correct even a complex farsighted astigmatism and restore visual acuity in full.Therefore, one should undergo an ophthalmic examination every year and do not delay visiting the oculist when symptoms appear in the article.
Zubkova Olga Sergeevna, medical reviewer, epidemiologist doctor