What is myopia and hyperopia?

Our eyes allow us to get the most complete information about the world around us, but when it appears myopia or hyperopia, then without vision correction tools, we begin to feel uncomfortable and uncertainly.

Myopia (myopia) and hyperopia (hyperopia) are the most common pathologies of vision.We will talk more about what these two violations are.

Physiological features of vision

Vision means a psychophysiological function that gives a person the opportunity to perceive and distinguish between the movement, location and colors of objects in the surrounding world.Thanks to the work of the visual system, which allows us to perceive light stimuli and objects, in conjunction with the higher parts of the central nervous system, we can see.

Anatomical structure of the eye

The eye perceives the image due to the fact that the flow of light rays moves through its media.

Firstly, it passes through the cornea, then through the anterior and posterior chamber of the eyes, through the lens and vitreous body, and finally, gets on the retina.

Due to the yellow spot and the central fossa of the retina, which are located opposite the pupil near the exit of the optic nerve, the image is focused.

The image falls on the retina in an inverted, reduced form.To clearly see the object, the lens changes its curvature. Curvature can change under the influence of the ciliary muscle, which can either strain or relax.

Normally, the rays should focus on the retina. This is called emmetropia. Ametropia is a deviation from the norm when the focus is in front of the retina (nearsightedness) or behind it (farsightedness).

Myopia

Myopia or myopia is a vision pathology, characterized by the fact that the image focus is in front of the retina. Therefore, a person sees badly into the distance, but clearly sees close.In short-sighted people, the eye can be enlarged in length or the cornea can have a great refractive power. In the first case myopia is called axial, and in the second - refractive.

Visual acuity in myopia can be less than one, so shortsighted glasses or lenses with a negative value are prescribed.

As practice shows, in most cases, myopia occurs between the ages of six and twenty. This age group includes schoolchildren and students.

Causes of myopia development:

• Hereditary predisposition.If parents are short-sighted, then there is a high probability that their children will also have myopia.
• Excessive eye strain and eye strain.Myopia is a frequent companion of those people who, due to their work, are forced to work with objects at close range. In addition, poor lighting and improper planting behind the workplace can also trigger the onset of myopia.
• Wrong correction of vision or lack thereof.This leads to the progression of the disease.

Treatment of myopia:

1. Glasses, contact lenses.
2. Photorefractive keratectomy.
3. Laser vision correction.

Photorefractive keratectomy

Hyperopia

Hyperopia or hypermetropia is a vision pathology, characterized by the fact that the image focus is behind the retina.In this case, the length of the eye decreases, so a person can not see closely located objects, but at the same time sees well into the distance.With farsightedness, the refractive power is rather weak, so that the focus is on the retina, the muscles that change the curvature of the lens are overstrained.

With hypermetropia, there may be a deterioration of vision in the distance (especially with a high degree of hypermetropia).

In addition, with excessive eye strain, headaches and burning can occur, and various inflammatory diseases can often develop, for example, blepharitis, conjunctivitis, haljazion and so on.Children may experience amblyopia or strabismus.

For the treatment of hyperopia, methods such as:

1. Glasses, contact lenses.
2. Photorefractive keratectomy.
3. Laser thermokeratoplasty.
4. Lens replacement.
5. Implantation of the lens.

Types of artificial crunches or intraocular lenses

Methods for determining hyperopia and nearsightedness

Generalizing factors (stages of the disease)

Both hyperopia and myopia can have three stages:

1. Weak;
2. Average;
3. Heavy.

Regardless of whether a person has myopia or hypermetropia, he needs to visit an ophthalmologist twice a year.

Regular check will allow you to track the progression of the disease and promptly select new glasses or contact lenses.It will also allow to detect dangerous diseases in time, for example, glaucoma and cataract, which are frequent companions of myopia and hyperopia.

Hyperopia

For the definition of hyperopia there are the following methods:

• Checking visual acuity with the help of tables.Allows you to determine the number of lines visible to the patient without correction.
• Computer diagnostics of vision - autorefractometry.Using this method, you can measure the optical strength of the eyes. Also autorefractometry allows to diagnose astigmatism.
• Measuring the optical power of the cornea - keratometry.
• Cycloplegia - dilated pupils with the help of eye drops.Drops block the work of the ciliary muscle, which makes it possible to detect latent farsightedness.

Types of image distortions in hyperopia

• Skiascopy and autorefractometry on the dilated pupil.It allows to determine the true degree of hypermetropia. Skiascopia is usually performed for children, because it can be difficult to focus the eyes.
• Measurement of eye length using ultrasound.The length of the eye is determined to assess the degree of hypermetropia. The method is needed to conduct surgical interventions to treat this disease.

Sometimes such an additional method of determining hyperopia as topography of the cornea is used. In farsighted people, the cornea is usually thickened. Another method that is used for people after forty years is gonioscopy. It allows to determine the state of the angle of the anterior chamber of the eye.

Myopia

To determine myopia, the following methods exist:

• Checking visual acuity with the help of tables.In this case, a set of trial spectacle lenses is used. This method is rather subjective and should be carried out in combination with other methods, for example, with skiascopy and refractometry.
• Ophthalmoscopy and biomicroscopy.Used Goldman's lens, which allows you to find pathological changes in the retina.
• Ultrasound diagnosis.It is used to measure the anteroposterior axis of the eye and the size of the lens, assess the vitreous humor and diagnose retinal detachment.
• Diagnosis of visual fields.

Additional methods for diagnosis of myopia (for example, aberrometry) are usually prescribed before the operation.

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conclusions

Signs of myopia and hyperopia occur in most people in the world. It should be remembered that these diseases can progress. Therefore, it is very important to contact the ophthalmologist when the first symptoms of impaired vision appear. A timely diagnosis and a properly selected treatment will protect the eyes from further progression of these diseases. Remember that myopia and hypermetropia of a mild degree can still be cured in the early stages of the disease.