Many eye diseases begin with symptoms that prospective patients do not take seriously. Redness of the eyes, inability to focus, double vision, headache are associated with fatigue, prolonged work at the computer and stress at work. At the same time, these signs can be the first symptoms that indicate a developing disease – myopic astigmatism, which, if left unattended, can lead to even more serious vision problems.
Myopic astigmatism is a combination of two ophthalmic ailments, myopia and astigmatism. With this disease, there are manifestations of both of its components: the visual distortion of the picture characteristic of astigmatism is complemented by the fuzziness and blurring characteristic of myopia.
Slight curvature of the lens and cornea can be found in 99% of the world’s population. However, in most cases, deviations from the norm are so small that they do not affect visual acuity and the quality of everyday life at all. A person begins to feel discomfort when the magnitude of the curvature is 0.75 diopters and above. The picture perceived by a person with myopic astigmatism most of all resembles a reflection on the surface of an oval spoon: it is just as twisted, stretched and fuzzy.
Mechanism of the disease
Rays of light entering the healthy eye are focused at one single point – the macula (zone of best vision) – which is located on the retina. This is possible only if the spherical shape of the eyeball, cornea and lens are not deformed. Distortion of forms leads to scattering of rays: refracting, they fall on different areas.
As a result, the image is perceived as stretched (horizontally or vertically, depending on the pathological shape of the eye). If at the same time the rays are focused not on the retina, but in front of it, signs of myopia are added: the farther objects are located, the less clear the patient sees them .;
For the diagnosis of myopic astigmatism, it is important to study the lines of incidence (meridians) of refracted rays. Usually, two main meridians are distinguished for each eye: with the largest and smallest refractive power. The difference between them will indicate the magnitude of the disease in diopters. The axis of astigmatism, obtained by comparing the direction of the meridians, will be expressed in degrees.
Causes of myopic astigmatism
The causes of the appearance of the described disease can be both congenital and acquired. Here are the main ones:
- congenital curvature of the lens;
- hereditary predisposition;
- injuries of the eyeball, cornea, lens, orbit;
- diseases that occur with impaired ocular circulation or increased eye pressure (diabetes and other endocrinological ailments, diseases of the heart and nervous system);
- consequences of surgical interventions (removal of cataracts, etc.);
- keratoconus (degeneration of the cornea with a change in shape from spherical to cone-shaped);
- complications after infections;
- constant eye strain.
Myopic astigmatism can appear at any age, but if an adult patient immediately pays attention to changes in visual perception, then children, especially those suffering from a congenital form of myopic astigmatism, simply do not understand that they see the world around them incorrectly. Due to the lack of complaints, the diagnosis of the disease in babies is difficult.
Symptoms of the disease
In addition to the symptoms listed above, adults may feel the need to squint frequently to see an object, increased tearing, and distortion of the geometric shape of objects.
You can suspect the development of the disease in a child by the fact that the baby often rubs his eyes, squints, tries to sit closer to the TV when watching cartoons.
Types of myopic astigmatism
Depending on how many main meridians are focused in front of the retina, simple and complex myopic astigmatism is distinguished.
- For simple myopic astigmatism, separation is characteristic: only one of the main meridians will be myopic, while the second will be correctly focused in the macula.
- Complex myopic astigmatism of both eyes in adults and children is characterized by the presence of signs of myopia of varying degrees simultaneously on each of the main meridians.
- There is also a mixed form – when there is myopia in one of the meridians, and farsightedness in the other.
Degrees of myopic astigmatism
Depending on the power of refraction of light, ophthalmologists distinguish the degree of the disease. There are three of them – weak, medium and high.
- Weak degree (up to 3 diopters).
Usually does not cause complaints in patients and is detected during a preventive examination by a specialist. The prognosis for such a small deviation is favorable. The disease lends itself well to correction with the help of optics or laser correction.
- Average degree (3-6 diopters).
Stage of perceptible discomfort: the patient comes to the ophthalmologist with complaints of visual impairment, poor health, eye fatigue. Correction of mild myopic astigmatism will be effective when using lenses, laser intervention. In some cases, surgery may be required to treat moderate myopic astigmatism.
- High degree (more than 6 diopters).
It is characterized by gross curvature of the cornea or lens. A combination of surgical and laser correction or hard contact lenses can help the patient: myopic astigmatism lends itself well to correction when using them.
Without adequate treatment and consultation with an ophthalmologist, a complex degree of myopic astigmatism can lead to uncorrected image distortions and other ophthalmic pathologies.
Experts recommend not to ignore even a slight deterioration in the condition of the organ of vision. Any complaint is a reason to consult a doctor for diagnosis and, if necessary, for recommendations for the treatment of myopic astigmatism.