Farsightedness, hyperopia: Why does impaired near vision occur?

Farsightedness is an innate and hereditary refractive error of the eye, which is characterized by impaired near vision.

Looking at distant objects is not a problem.

A person is already born with this defect and gradually, as the eye develops and grows, it adjusts. It persists to a higher degree in about 6% of cases. If not addressed in time in this case, it can cause squinting and amblyopia.

Farsightedness is also referred to as hypermetropia or hyperopia.

Until the 5th to 6th year of life, the human eye develops and grows. After birth, the newborn has imperfect vision, which does not allow him to see sharply. Everything at a distance of over 25 cm is blurred.

In the 2nd month, he begins to follow the objects in front of him and straightens his eyes, fixing it. During this period, it is not exceptional or occasional squinting. Bilateral cooperation is not improved until around the 6th month. Then it begins to perceive spatially.

Binocular vision and the connection of both images into one whole develops most significantly during the first year. Subsequently, visual functions are improved. And until the 5th - 6th year of life.

Eye growth is significant until puberty and about 14 years of age. Subsequently, it slows down and the eye grows by about 0.1 mm per year.

The newborn's eye has an anteroposterior eye length of approximately 18 mm and an average of 23 mm in three years.

What is a refractive error?

It's not a disease.

Refraction of the eye indicates the ratio between the optical refraction of the eye, and thus the optical members, and the anteroposterior length of the eye. The emmetropic eye is one that sees well. This ensures that the light in the eye converges and forms a sharp image on the retina of the eye.

Ametropia, on the other hand, is a condition where the image converges in front of or behind the retina. As a result, a sharp image is not produced on the retina.

Refractive errors are then divided into spherical, ie myopia and farsightedness, and aspherical, namely astigmatism.

Myopia is characterized by the rays of light converging in front of the retina. In this case, the defect is corrected by scattering, i.e. by concave lenses.

In the case of farsightedness, the convergence of light rays is beyond the retina and is corrected by couplings, ie convex lenses.

Astigmatism is characterized by an uneven curvature of the optics. Cylindrical glasses are used for correction.

How is farsightedness distributed?

Hyperopia is divided into latent and manifest. Latent is one that does not manifest itself in childhood, because the accommodation range of the eye lens is sufficient with correction and does not burden the eye so much.

Manifestation is manifested by increased accommodation efforts, which overloads the ciliary muscles.

The ciliary muscles change the thickness of the eye lens, which leads to a change in the radius of curvature. The lens is elastic and the change in its power ensures that the image is sharpened on the retina.

The table shows the distribution of farsightedness

In childhood, farsightedness may not show. However, it depends on the scope. And also from this point of view, it is subsequently divided.

Hyperopia breakdown by degree:

1. Slight farsightedness when the diopter range is + 0.25D to 3.0D
2. Moderate farsightedness, in the case of values from + 3.25D up to + 6.0D
3. High farsightedness at values ​​at  + 6.25D
   • a severe defect above + 9.25D indicates impaired vision even at near or far

The cause of farsightedness is in most cases an axial defect. This means that the eye is shorter in the anteroposterior plane, which causes the light rays to converge behind the retina.

The image is drawn sharply on the retina and is blurred.

The eye is usually shortened to 2 mm, which causes a refractive error of less than + 6D.

Shortening the eye is usually the result of its slow growth. At other times, the thickness of the eye lens is increased behind farsightedness, in this case, also referred to as physiological hyperopia.

In some cases, other diseases may be the cause, such as:

• Inflammation of the eye
• retinal detachment
• injury
• a tumor in the back of the eye that pushes on the eye
• aphakia, ie the absence of an eye lens
• diabetes as its secondary cause

Hypermetropia has been present in humans since birth. It disappears over time. However, if it persists, it manifests itself in the poor vision of nearby objects.

It is difficult to read, but also to watch television. Conversely, until a severe degree is present, distant objects are visible well.

The child's eye and the eye in youth are very well able to accommodate. A small difference of a few diopters may not even show. The latent form tends to be well corrected in childhood, however, in adulthood, it can create minor difficulties.

At about the age of 45, every person develops presbyopia, ie amblyopia.

Read also: Visually impaired , why does our vision worsen after forty?

Presbyopia occurs more in people who suffered from farsightedness even before the age of 40. Conversely, those with myopia may expect it later or to a lesser extent.

Symptoms and associated difficulties with farsightedness:

• problem with reading, painting
• difficulties with fine motor skills
• increased fatigue
• headache
• eye fatigue
• redness of the eyes
• problem with focus and focus when reading
• frequent blinking
• squint
• burning and cutting eyes
• in childhood also schooling
• nausea

Let's recognize farsightedness in children in time

Not only farsightedness but also other visual disorders are the cause of the slowing down of psychomotor development. Hypermetropia above + 3.50D indicates an increased risk of impaired cognitive and motor functions in childhood.

Particular attention should be paid to parents with visual impairment.

In school-age children, it is the cause of problematic learning, impaired performance. The child makes mistakes in reading and writing. 

In young children and children of preschool age can be noticed:

• more frequent blinking and rubbing of the eyes
• squint
• closing one eye
• training
• bringing objects closer to the eyes, toys, books
  • which reduces the distance and enlarges the object
• When drawing and painting, tilt your head closer over the pad
• head tilt
• increased fatigue during nearby operations
• faster loss of interest in books or coloring books
• reduced concentration, lack of concentration or restlessness and distraction
• problem with fine motor skills
• sitting closer to the television
• burying and bumping into objects
• complains of headache

It is often overlooked in childhood. In most cases, parents realize that there is a problem at school age. Therefore, regular and thorough vision control is very important in preschool age.

The basic examination of visual acuity will be performed by a general practitioner for children and adolescents, using an optotype as a simple test. In case of discrepancies, an eye examination is required.

Screening eye examinations are performed after the birth of a child, in the 3rd, 6th, 12th, 18th month and in the 3rd year, then every 2 years. 

An ophthalmologist, ie an ophthalmologist, may also notice a more developed ciliary muscle, which helps to accommodate the eye lens. A narrower pupil or enophthalmos (entrapment of the eye in the orbit) is usually present, intraocular pressure increases, manifestations are also present on the macula (yellow spot) or papilla of the optic nerve (optic nerve output), vascular changes.

The examination is performed with the help of an ophthalmoscope, ototype, refractometer.

The ability to accommodate the lens - cyclopllegia - is excluded from the examination. Cycloplegics eliminate accommodation and also widen the pupil. They are given in the form of eye drops.

In the case of a lower degree, it may not even be detected in childhood. Thus, visual impairment occurs only in adulthood.

If it is a more serious form, we may notice a reduced interest in the child's books or drawing and painting. He sits closer to the television. Other activities in the near distance and fine motor skills are also problematic.

It squints, more often blinks, closes one eye, or tilts its head. Alternatively, the child also complains of headaches and increased fatigue of the eyes, which he rubs and has bloodied.

At school age, we encounter problematic learning, the child makes mistakes in reading and writing.

An adult at the age of about 45 naturally loses visual acuity, which is referred to as presbyopia. In this case, Farsightedness begins earlier.