Often you hear questions from uninformed people about how farsightedness is a plus or minus. In order to correctly answer such questions, it is necessary to understand the principle of the human organs of 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, you need to consider what the human eye consists of.
Eye structure
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 with the help of which light signals diverging on the sides are focused.
- The sclera is an external opaque shell of the eye that does not take an active part in the transmission of light.
- The iris is a kind of aperture of the camera. This part regulates the flow of light particles and performs an aesthetic function, determining the color of the human eye.
- The pupil is an opening in the iris that controls the number of light rays entering the eye, as well as sifting out distorting curves.
- The lens is the second most powerful lens in a given human organ, located just behind the iris. Depending on the distance to the subject, it changes its optical power. With a small distance it strengthens, with a large distance it weakens.
- The retina is the spherical surface onto which the world is projected. Moreover, the light, passing through two collective lenses, falls on the retina in an inverted form. Then the information is converted into electronic pulses.
- The macula is the central part of the retina that recognizes a clear color image.
- The optic nerve is a transporter of the processed retina into nerve impulses of information to the brain.
Types of Vision Problems
Vision problems can occur at any age (can even be congenital). The cause of some of them is a violation 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” mean the degree of refraction of light (either the rays are not refracted enough, or they are refracted too much). There are several main types of visual impairment in humans.
Myopia - this is myopia
With myopia, a person does not see objects that are at a great distance. Close while normal vision. With this disease, you can easily read a book, but the house number, which is located across the road, can no longer be seen.
Is farsightedness a plus or minus?
Back to the main question. So, is farsightedness a plus or a minus? Farsightedness (aka hyperopia) is a visual impairment in which a person does not distinguish objects that are close to him, but he perfectly distinguishes small details of distant objects.
So, the strength of the points prescribed to the patient is measured in diopters. With farsightedness, glasses with a collecting effect are placed, which perform part 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, the treatment uses glasses with a scattering effect, which are called negative.
Presbyopia - what is it?
Hyperopia age-related in the medical environment is called presbyopia and is found mainly in people over 40 years old. This disease is caused by the loss of lens elasticity and is expressed by the loss of the ability to change the eye focus when looking at objects located at different distances.
Astigmatism
The visual impairment 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 is the cause of cataracts?
Cataracts are a very common disease that causes visual impairment. Most often occurs at a young age, but it can also be a consequence of a viral disease. A manifestation of this ailment is a clouding of the lens.
I propose, in the framework of this article, to consider in more detail issues related precisely to farsightedness.
The main causes of farsightedness
So, as already mentioned, hyperopia is an eye disease in which the image focuses behind the retina. The degree of development of hyperopia depends on the ability of the eye to refract light rays and on accommodation (the properties of the lens change its shape depending on the distance to the subject):
- Weak (up to +2 diopters).
- Medium (from +2 to +5 diopters).
- Strong (more than +5 diopters).
There are two reasons for farsightedness:
- The eyeball is too short, and therefore the short longitudinal axis of the eye. Most often, this visual disturbance is hereditary.
- Insufficient 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.
Farsightedness Symptoms
The main symptom is poor near vision . At the same time, objects that are away, the patient sees well. However, over time, the pathology may increase due to the loss of accommodation properties of the lens.
The main symptoms, the presence of which prompts to turn to the ophthalmologist with suspected hyperopia, belong to:
- Violation of "near" vision.
- Violation of "distant" vision.
- Increased eye fatigue during work.
- Visual fatigue when reading books.
- Frequent conjunctivitis and other inflammatory processes of the eyes.
- Strabismus in childhood.
Diagnosing 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:
- The study of visual acuity. For this purpose, a special vision table is used. Now we use the tables of Sivtsev, Golovin or Orlova (mainly in children).
- Examination of the fundus using a mirror, as well as ultrasound.
3. The selection of lenses of the required power, carried out using a foropter.
Farsightedness treatment
In order for you to never be bothered by vision problems, you must be guided by the following principles:
- Observe the lighting mode.
- Alternate visual loads with physical discharge.
- Train the visual muscles with the help of special exercises for the eyes, as well as using modern technologies (including computer and laser).
- Carry out early diagnosis and correct vision correction (includes a mandatory periodic examination by an optometrist).
- Perform general strengthening exercises, supported by proper nutrition.
The implementation of these preventive measures will save vision. Plus, of course, do not forget to undergo periodic examinations by an optometrist.
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 moving forward in huge strides and now allows a person to stop wondering whether hyperopia is a plus or minus.