The scientific name of myopia — myopia comes from the Greek word “myops” — “squint”, as people with this pathology are forced to narrow their eyelids to look at something far away. According to statistics, more than a third of the world’s population suffers from myopia. If the degree of visual disorder is small, many people do not even know about it.
How is myopia formed
The eye is a finely tuned optical device in which the lens functions are performed by the lens, and the stability of the work is provided by special muscles. Normally, the image of surrounding objects is formed on the retina — a multi-layered shell of the fundus, consisting of photosensitive, color-sensitive receptors and many nerve endings. The clarity of the picture is provided by the ideal length of the eyeball camera — about 23 mm. The rays, passing through its transparent media, focus directly on the surface of the mesh shell.
If for some reason the sclera of the eyes stretch – by fractions of a millimeter or a little more, the focus when looking into the distance shifts forward, not reaching the retina. As a result, the brain gets a blurry fuzzy picture, while the eye scans closely located objects as clearly as before. This condition is commonly called myopia or myopia.
The condition in which the ocular axis is lengthened by 0.33 mm corresponds to myopia -1 diopter. The main symptom of myopia is a decrease in visual clarity, blurring of the contours of surrounding objects. The more pronounced the violation, the more unclear they are seen. There are 3 degrees of pathology in total:
- weak: up to -3 diopters: a slight feeling of blurring, while distant vision is completely corrected by glasses or contact lenses;
- average: from -3 to -6 diopters: visual disturbances require constant correction, glasses or lenses are necessary not only for distance, but also for work;
- high: more than -6 diopters: leads to stretching of the fundus vessels, myopic complications, without glasses or lenses, patients cannot fully work and navigate in space.
Myopia can be accompanied by constant eye fatigue, sensations of flying midges, particles or dust particles, general blurred vision. With high myopia, which can reach 30-40 diopters, complications are inevitable. In most cases, these are astigmatism, dystrophic changes in the periphery and macula of the retina, impaired blood supply to the eyes.
Causes of myopic changes
The elongation of the optical axis of the eyes is the direct cause of a decrease in distant vision. Less often, the focus is distorted due to corneal and lens pathologies. Sometimes all these violations are combined. Myopia usually develops in childhood or at a young age. In adults, it debuts infrequently. The main risk factors:
- spasm of the muscles of accommodation and stretching of the sclera regulating eye movement: due to high, prolonged visual loads near;
- systemic diseases;
- general physical exhaustion;
- injuries and circulatory disorders of the brain;
- malnutrition: deficiency of vitamins and minerals necessary for vision;
- genetic abnormalities: intrauterine disorders, naturally weak connective tissue, poor heredity, chromosomal diseases.
Depending on the causes and periods of development , myopia can be:
- false: without anatomical changes in the structure of the eyes, occurs for several days, weeks or months due to high or unusual visual loads, it often affects children of primary school age;
- true: the formed disorders have a permanent irreversible character, such a disorder occurs in adolescents and adults.
A condition in which vision weakens by 1 diopter or more over the course of a year is called progressive myopia. It is observed in most children in the absence of optical vision correction or ignoring treatment. Stationary myopia without progression occurs in adults. By adulthood, the eye tissues become less elastic, cease to stretch excessively. After 45 years, due to age-related changes, the degree of myopia may decrease somewhat.
Diagnosis and correction of myopia
The first sign of myopia is the inability to clearly see the letters in the visometric table. To determine the degree of myopia and the existing complications on the fundus, a comprehensive examination is performed:
- Ultrasound of the eyes.
In the presence of concomitant systemic disorders and deterioration of well-being, intraocular pressure is measured, the fields of vision boundaries are determined. Progressive myopia requires dynamic follow-up.
The revealed visual impairment is corrected by changing the natural refraction of the rays so that they focus on the retina. Glasses with diffusing lenses of a certain curvature or contact lenses are used. The latter are:
- for daytime wear: disposable or long-term use, they are made of soft vapor-permeable or dense plastic;
- orthokeratological: solid, designed to be worn at night, provide a reduction in myopia in the following days.
A more comfortable permanent correction of myopia is carried out by microsurgical surgery on the cornea. Special laser equipment is used. LASIK, FEMTO LASIK, PRK and others techniques allow you to get rid of wearing glasses and lenses forever or for many years. Laser correction does not affect the complications of myopia and its immediate causes. The disease persists after it is carried out.
Treatment of myopia
Myopia is not just a visual impairment. This is a complex pathological process that needs to be stopped in development. Conservative treatment consists in the use of medications:
- phenylephrine preparations;
- vitamins of group B, A, ascorbic acid: orally, by injection;
- complexes containing antioxidants, lutein;
Patients with myopia require a year-round healthy diet: vegetables, herbs, fruits, a sufficient amount of protein and fats. Heavy physical activity is prohibited: lifting weights, working in an inclined position, practicing extreme sports.
To prevent the development and progress of the disease, it is recommended to perform special gymnastics daily to strengthen accommodation, relieve eye fatigue, and dose visual loads. In clinical conditions, myopics are prescribed laser stimulation, color pulse therapy.
The surgical method of preventing progressive myopia is scleroplasty. Elastic biological implants are placed behind the fibrous membranes of the eyeballs, preventing the stretching of the sclera. In severe cases, corneal transplantation, partial or complete replacement of lenses with special artificial lenses are indicated.