Myopia: symptoms and causes

Myopia is defined as defective vision in which nearby objects are clearly seen but distant objects appear blurry.

Myopia occurs when the eyeball is too long or the cornea (the anterior transparent surface of the eyes) has too much curvature.
The object image takes place in front of the retina, the light-sensitive part of the eye, instead of directly on the retina and creates a blurred visual impression.

As a result, the light entering the eye is not properly focused and distant objects appear blurred.
As a rule, myopia begins in childhood. In most cases, it then stabilizes around the age of 20/25, but sometimes it continues to worsen over the years.Types of myopia

Classification according to anatomical criteria

Axis myopia
The origin of axis myopia is an increased axial length of the eye.

Refractive myopia
Refractive or refractive myopia depends on the condition of the refractive parts of the eye; It can be further divided into:

  1. Curvature myopia – caused by the increased curvature of the cornea or lens.
  2. Index myopia – caused by the change in the refractive index of the lens, for example in cataracts (cataracts).


Classification by symptoms

Simple myopia simplex
This is the most common form of myopia and is characterized by an eye that is too long for his vision. Simple myopia rarely reaches 10 diopters. There are no changes in the cornea or other eye structures.

Degenerative myopia
Degenerative myopia (also called malignantprogressive or pathological myopia) is characterized by changes in the fundus. This form of myopia deteriorates continuously throughout a lifetime. Degenerative myopia is one of the main causes of visual impairment because the patient can achieve a serious loss of vision. Causes include:

  • Glaucoma
  • Macular degeneration
  • Retinal or vitreous detachment.

Night myopia
This disorder is characterized by vision problems in low-contrast visibility, while daytime vision is normal. In a poorly lit environment, the eye experiences an increase in accommodation. Night myopia is more likely to affect young people than older people.

This disorder is caused by a spasm (unwanted muscle contraction, often accompanied by an increase in volume) of the ciliary muscle.

Induced myopia It is also called acquired or temporary myopia
and is caused by:

  1. some medications (e.g. diuretics),
  2. excessive glucose levels,
  3. Lens core sclerosis.
  4. The horizontal ligaments used to surgically treat retinal detachment can induce myopia by lengthening the axial length of the eye.

Deprivation myopia, for example, can develop if one eye remains connected for a long time.

Classification by degree and extent

Mild myopia
Less than 3 diopters.

Moderate myopia
Between 3 and 6 diopters.

Severe myopia Affects about 30% of myopia
and is more than 6 diopters.
People with severe myopia are more likely to:

  • Retinal detachment
  • open-angle glaucoma,
  • Mouches volantes (flying mosquitoes).

Classification according to time of origin

Congenital myopia This myopia, also known as infantile myopia
, is present from birth and persists throughout childhood.

Juvenile myopia
Myopia, which arose in childhood and adolescence, develops up to the age of 20 years.
According to scientists, the cause is heritability; In the past, it was thought that juvenile myopia was caused by overlearning, because the eyes are always focused on nearby objects.

Myopia in adults
Myopia, which arose in early adulthood, develops from the age of 20.

Causes of myopia

According to conventional medicine, the cause of myopia is genetic and environmental.

According to the blood group diet of Dr. D’Adamo and Mozzi, the visual impairments in children are caused by milk and dairy products in the diet.

According to the natural hygiene of Shelton, on the other hand, myopia has the following causes:

  • Insufficient eye activity
  • Poor lifestyle
  • Inappropriate nutrition

The structures of the eye are not hard and rigid, but flexible and can deform and adapt to the surrounding conditions.
Glasses reduce the adaptability (accommodation) of the lens and are therefore rejected by hygienists.

Living indoors and seeing up close
Various studies show that for improving or curing myopia, practicing outdoor activities is essential.

A 2008 study in Australia, in which 12-year-old children completed a program of outdoor activities during the day, shows a reduction in myopia within two years.

Another scientific study from Taiwan divided children aged 7 to 11 into two groups:

  1. The children regularly performed outdoor activities during the break.
  2. The children stayed in the building during the break.

The results after one year showed that only 8.4% of the first group had developed myopia, compared to the 17.6% of the second group.
In addition, the short-sighted children of the first group had only a deterioration of 0.25 diopters compared to 0.38 of the second group.

Symptoms of myopia

With myopia, the following symptoms may occur:

  • blurred vision of distant objects;
  • need to squint your eyes or partially close your eyelids to see more clearly;
  • headache, caused by overstrain of the eyes;
  • difficult vision when driving, especially at night (nocturnal myopia).

Myopia is noted in childhood, usually between the first years of school and adolescence.
A child with myopia can:

  • continue to squint your eyes;
  • feel the need to sit closer to the television, the screen in the cinema or in the front rows of the classroom;
  • hold books very close to your eyes while reading;
  • may not see distant objects;
  • often rub your eyes.

Diagnosis of myopia

The ophthalmologist can diagnose myopia as part of a complete examination.
The doctor determines by a standard procedure, which requires the patient to read:

  1. Letters on a blackboard on the other side of the room (Snellen-Augentafel);
  2. Sentences on the Jaeger table – a sheet of capital and lowercase letters, which allows close vision to be assessed.

If the eye test shows that the patient is nearsighted, the doctor uses some equipment to clarify what causes myopia.
It shines into the eye with a special lamp, then a retinoscope is used to see how the light is reflected by the retina.
The fact of how the light is reflected inside the eye can indicate whether a person is nearsighted or farsighted.

The doctor also uses a phoropter, an apparatus that measures the severity of the refractive error, and prescribes a suitable visual aid to correct it.

Therapy and lenses for myopia

The goal of myopia treatment is to direct the focus of light to the retina through the use of a corrective lens or refractive surgery.

Corrective lenses
Corrective lenses are used to treat myopia to compensate for a greater curvature of the cornea or a too long eyeball.

Types of corrective lenses are:

Corrective glasses. Glasses are available in different variations and they are easy to use.
Glasses can correct various visual disturbances such as myopia and astigmatism at the same time.

Contact lenses. A wide range of contact lenses are available:

  • hard lenses,
  • soft lenses,
  • disposable lenses,
  • rigid gas permeable (RGP) lenses,
  • bifocal lenses.

One should discuss with the ophthalmologist of the pros and cons and find out which is the best solution for the patient.
According to the hygienist Shelton, wearing glasses can only worsen vision, because the eye then does not try to make accommodation in the direction in which there are difficulties.
Immediately after removing the glasses, the patient sees even worse.
The body has incredible adaptability, here are some examples:

  1. Athletic performance can be increased through training.
  2. After an ankle fracture, strength and balance can be improved through rehabilitation and exercises.
  3. The bone is strengthened by physical activity, but weakened by lack of exercise (osteoporosis).

In conclusion, Shelton recommends avoiding glasses and straining their eyes to improve vision so that they learn to see even in difficult situations.
In case of myopia, glasses are often recommended to children or adolescents. However, these may have sudden vision problems triggered by:

  • inadequate nutrition,
  • Stress
  • excessive computer work.

The ophthalmologist usually advises the patient to wear glasses against myopia, as the eyeball is too long, although its length was actually correct until shortly before.

Research and new insights into myopia

A lot of research is being done to find methods to avoid exacerbation of myopia during childhood.

Recently, researchers in New Zealand have reported encouraging results with soft contact lenses specifically designed with “dual-focus” to treat myopia in children.
These prototypes have much lower power in the periphery of the lens than in the center.
It is believed that this “peripheral defocusing” may reduce the tendency to further lengthen the eyeball, leading to exacerbation of myopia.

In a study published in 2011, researchers found that in 70 percent of nearsighted children (ages 11-14) who wore a trial lens in one eye and a standard soft contact lens in the other, the progression of myopia in the eye in which the double-focus contact lens was worn was up to at least 30 percent lower.

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