What will you find in the article?
Not long ago we looked at the topic of myopia. There we thoroughly explained what it is, types and how to fix it.
But in order to be more detailed about the eyes, today we will pay attention to another of their conditions called hypermetropia (farsightedness).
In order to receive information about the world around us, the eyes perceive light rays reflected from everything around us every day. After their passage through the optical system of the eye, they fall into the central visual field in the retina. This happens when you have excellent vision, but when this is not the case, as in myopia, the image is formed in front of or behind the retina.
In this case, farsightedness is ametropia, in which the parallel beam of light that falls on the eye after refraction is collected behind the retina. As a result, the image is unclear and blurred.
If you remember in a myopic eye, this image was produced in front of the retina.
Farsightedness is the most common refractive condition in children because their eyes are not yet sufficiently developed and the size of the eye axis is smaller. Over the years, it grows, therefore, in most cases, ophthalmologists say that hypermetropia in early childhood can be outgrown.
Types of hypermetropia (farsightedness)
Depending on the cause
Axial
It is due to a shorter axis of the eye.
Refractive
It is a consequence of the reduced refractive power of the optical system of the eye.
Mixed
It is, as you might guess, a combination of the previous two.
Depending on the need for correction
Hidden (latent)
This hypermetropia does not need correction. It is compensated by the tone of the eye.
Manifest (manifest)
It requires correction. It is measured in narrow pupils.
Total
It combines the overt and the hidden and is measured after dilating the pupils.
Normal farsightedness grows to +8.00 dpt.
In fact, long-sighted eyes see far and need help for near.
As we age, the accommodative ability of the eye weakens. This is due to the reduced elasticity of the lens, as a result of which its refraction also decreases.
It is believed that after the age of 70 the accommodation (the ability of the eye to focus at all distances) is 0 dpt.
The decrease in the accommodative ability of the eye is called presbyopia (age-related farsightedness). In this case, a correction is required for near, and with advancing age, for far. It is corrected with progressive glasses. We covered more about them in the topic dedicated to progressive glasses.
But now let's get back to hypermetropia. It is corrected with a positive correction lens.
It is necessary that the rear focus of the glass coincides with the far point of the farsighted eye. The refractive power of the positive correction lens depends on the magnitude of the ametropia and the distance between the lens and the cornea.
The positive corrective lens has converging power.
More familiar to people is the concept of reading glasses. They are the medium that aids in reading the fine print.
A lot of people put their glasses on in the middle of the nose, not on the top, as it should be. Thus, they increase the dioptric correction of the glasses (the distance between the glass and the cornea increases). In fact, this manner of wearing is used for convenience because a farsighted person can read and look over their glasses to see in the distance. If he looks far away through his reading glasses, he will not see clearly.
And while the myopic eye is "greedy" it should not be overcorrected, the farsighted eye needs to be at maximum correction.
Hypercorrection is when on a myopic eye, the maximum permissible correction found during the examination is placed.
Hypermetropia can be corrected with glasses, contact lenses, or laser vision correction. Laser vision correction is performed on patients between 18 and 40 years old. It is safe, bloodless and seamless.
What is the vision in hyperopia (hypermetropia)?
People suffering from farsightedness experience difficulty seeing when reading and working on a computer. Images observed at close range are unclear and blurry. Some farsighted people compensate for this need by straining the eyes, but this often leads to severe headaches.
Symptoms of hyperopia (hypermetropia)?
- Blurred vision of nearby objects;
- Need to distance the observed close object;
- Eye fatigue, redness and pain;
- General discomfort of the eyes, a consequence of observing close objects;
Read more about eye conditions
Our eyes are often imperfect. The vast amount of information passing through them exhausts and sometimes damages them. One common condition is myopia (nearsightedness).
It is an ametropia in which the parallel beam of light that falls on the eye collects somewhere in front of the retina. As a consequence, the image that results is blurred. Simply put, a myopic person cannot see "further than their nose". The myope can read and see up close, but when he looks into the distance, he sees blurry.
It's time to talk about the famous Astigmatismthat scares every one of us when we hear that it is there. But there is nothing scary or irreparable about it. In fact, astigmatism is a handicap which the optical system does not refract equally in its different sections.
Now you get it, right? Perhaps, it would sound simpler like this: the sections are horizontal and vertical ( meridional and sagittal), when the parallel beam of light passes through, it is not refracted equally in both sections.