One often hears questions from ignorant people about whether farsightedness is a plus or a minus. In order to correctly answer such questions, it is necessary to understand the principle of the human vision and to study the possible problems that may arise.
The eye is one of the most complex organs in the human body. The interaction of the visual system with the cerebral cortex allows you to convert the rays of light coming from the outside world into visual images. To understand how this happens, it is necessary to consider what the human eye consists of.
The structure of the eye
The eye is a very complex optical system that consists of many parts.
- Cornea. Through it, light waves enter the eye. It is an organic lens that focuses light signals diverging on the sides.
- Sclera is the outer opaque shell of the eye, which does not actively participate in the conduction of light.
- The iris is a kind of camera aperture. This part regulates the flow of light particles and performs an aesthetic function by determining the color of a person's eyes.
- Pupil - a hole in the iris that regulates the amount of light rays entering the eye, as well as screening out curved distorting rays.
- The lens is the second most powerful lens in this human organ, located just behind the iris. Depending on the distance to the object, it changes its optical power. At a short distance, it strengthens, at a large distance, it weakens.
- The retina is a spherical surface onto which the surrounding world is projected. Moreover, the light, passing through two collective lenses, hits the retina inverted. The information is then converted into electronic impulses.
- The macula is the central part of the retina that recognizes a sharp color image.
- The optic nerve is the transporter of the processed retina into nerve impulses of information to the brain.
Types of vision problems
Vision problems can appear at absolutely any age (they can even be congenital). The cause of some of them is a malfunction of the retina or optic nerve. However, most diseases of the visual system are provoked by a violation of the refractive characteristics of the eye. The consequence of this is defocusing, and a person loses the ability to clearly see objects. That is, human vision is impaired. "Plus" and "minus" in this case indicate the degree of refraction of light (either the rays are not refracted enough, or they are refracted too much). There are several basic types of violationhuman vision.
Myopia is myopia
With myopia, a person does not see objects that are at a great distance. Up close, vision is normal. With this disease, you can easily read a book, but you can no longer see the number of the house that is across the street.
Is farsightedness a plus or a minus?
Let's get back to the main question. So, is farsightedness a "plus" or a "minus"? Farsightedness (aka hypermetropia) is a visual impairment in which a person does not distinguish objects that are close, but perfectly distinguishes fine details of distant objects.
So, the strength of the glasses prescribed to the patient is measured in diopters. With farsightedness, glasses with a collecting effect are placed, which perform some of the functions of the lens. Such glasses are called positive, and therefore farsightedness is a plus. Or "minus", for example, is used for myopia. Therefore, glasses with a scattering effect, which are called negative glasses, are used in the treatment.
Presbyopia - what is it?
Presbyopia in the medical environment is called presbyopia and occurs mainly in people over 40 years of age. This disease is caused by the loss of elasticity of the lens and is expressed by the loss of the ability to change the eye focus when looking at objects at different distances.
Astigmatism
Impaired vision, characteristic of astigmatism, occurs as a result of a change in the curvature of the lens and is expressed in the incorrect refraction of light rays. Because of this, the picture of the outside world looks somewhat distorted.
What causes cataracts?
Cataract is a very common disease that causes visual impairment. Most often occurs at an elderly age, but it can also be the result of a viral disease. A manifestation of this disease is clouding of the lens.
I propose, within the framework of this article, to consider in more detail issues related specifically to farsightedness.
Main causes of farsightedness
So, as already mentioned, farsightedness is an eye disease in which the image is focused behind the retina. The degree of development of hypermetropia depends on the ability of the eye to refract light rays and on accommodation (the properties of the lens to change its shape depending on the distance to the object):
- Weak (up to +2 diopters).
- Medium (+2 to +5 diopters).
- Strong (more than +5 diopters).
There are two causes of farsightedness:
- Too short eyeball, and consequently, a short longitudinal eye axis. Most often, this vision disorder is hereditary.
- Inadequate refractive properties of the visual system. With age, the human lens loses its elasticity and corresponding abilities.
There is also the possibility of a combination of these two reasons.
Symptomsfarsightedness
The main symptom is poor near vision. At the same time, the patient sees objects that are far away well. However, over time, the pathology may increase due to the loss of the accommodative properties of the lens.
The main symptoms, the presence of which prompts you to consult an ophthalmologist with suspicion of hypermetropia, include:
- Violation of "near" vision.
- Violation of "distant" vision.
- Increased eye fatigue at work.
- Visual fatigue when reading books.
- Frequent conjunctivitis and other eye inflammations.
- Squint in childhood.
Diagnosis of vision problems
As soon as you feel a decrease in visual acuity, you need to seek help from a specialist. The standard diagnostic procedure includes the following steps:
- Study of visual acuity. For this purpose, a special table of vision is used. Now the tables of Sivtsev, Golovin or Orlova are used (mainly in children).
- Research of the fundus with a mirror, as well as ultrasound.
3. Selection of lenses of the required power, carried out using a phoropter.
Treatment for farsightedness
In order for you to never be bothered by vision problems, you must be guided by the following principles:
- Observe lighting mode.
- Alternate visual activity with physical relaxation.
- Trainvisual muscles, both with the help of special exercises for the eyes, and with the use of modern technologies (including computer and laser ones).
- Perform early diagnosis and correct vision correction (includes mandatory periodic examination by an ophthalmologist).
- Perform general strengthening exercises, supported by proper nutrition.
The implementation of these preventive measures will save your eyesight. Plus, of course, do not forget to undergo periodic examinations with an ophthalmologist.
Vision correction is performed using glasses or eye contact lenses, which are prescribed to the patient in a special prescription after a full examination.
In addition, eye surgery is making huge strides forward and already now allows a person to stop wondering if farsightedness is a "plus" or "minus".
