How can you treat farsightedness?

Far-sightedness (hyperopia, hypermetropia) makes it difficult to see into the distance and especially close up. Glasses or contact lenses can help. Sometimes an operation, for example with a laser, is also an option

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Uncorrected farsightedness: When looking into the distance without accommodation, a sharp image only emerges behind the retina

© W & B / Alfred Neuwald

Far-sightedness - briefly explained

In farsightedness, either the eyeball is too short or the refractive power of the lens is too low. A sharp image is only created behind the retina.

Children and young adults can often compensate for farsightedness, at least in part, by more bulging of the lens as part of what is known as accommodation. At some point, however, this is no longer possible and, above all, close objects appear blurred to farsighted people. This leads to difficulty reading.

Glasses or contact lenses, and in some cases also an operation, for example with a laser, can help to compensate for the visual defect in farsightedness.

What is farsightedness?

Farsightedness (hyperopia, hypermetropia) is a form of ametropia. Far-sighted people like to hold books and magazines away from them by their outstretched arms to read them. Because while at a young age they are better able to see objects that are far away, what is close appears blurred to them.

When looking into the distance, the light rays falling almost parallel into the eye are bundled in such a way that a sharp image of an object is only created behind the retinal plane. The farsighted person compensates for this by changing the refractive power of his lens through the activity of his so-called ciliary muscle. A process called accommodation (see section "What causes farsightedness?").

This tactic often works well with objects far away and often at a young age. With objects very close, however, it becomes more difficult because the increase in lens power is limited. From around the age of forty, the elasticity of the lens and thus its refractive power also decrease (presbyopia), so that the symptoms of farsightedness increase and distant vision also decreases.

What is a diopter?

The refractive power of the eye is measured in the unit of dioptre (dpt). The normal value for a healthy eye at a great distance is around 60 to 65 dpt. In the case of ametropia, the number deviates from this value. How strong the deviation is in the individual case is indicated with a plus for farsightedness (for example +3) and a minus for nearsightedness.

What is the cause of farsightedness?

There are two different causes of farsightedness:

1) The eyeball is relatively too short (axis hypermetropia or axis hyperopia).

2) The refractive power of the cornea-lens-vitreous system is too low (refractive hyperopia or refractive hypermetropia).

Axial hyperopia is more common; the eyeball that is too short is usually congenital. The rather rare refractive hyperopia can have different backgrounds.

If you look into the distance, the rays of light emanating from a certain point on the horizon fall almost parallel into the eye. In a relaxed state, a farsighted person would only get a sharp image behind the retina due to the insufficient refractive power of the eye in relation to the length of the eyeball, as a focus to a point only takes place here (see figure).

The farsighted person can compensate for the inadequate refractive power of the lens in relation to the length of the eyeball either completely or partially by using a mechanism that we need for close vision: so-called accommodation.
The degree of curvature and thus the refractive power of our eye lens can be changed. This change is regulated by the so-called ciliary muscle. When looking into the distance, he is relaxed, but the so-called zonular fibers, on which the lens is suspended, are under tension and pull the lens into a more or less flat shape. If, on the other hand, the ciliary muscle tenses, the zonular fibers slacken. The lens adopts its normal shape with a distinct curvature. The more the lens is curved, the higher its refractive power. So if we want to look at objects nearby, we use our ciliary muscle to increase the refractive power of the lens and to adapt our eyesight, that is, to accommodate.

Far-sighted people also have to accommodate when looking into the distance in order to increase the refractive power of their lens and thus compensate for their visual defects and produce a sharp image on the retina. This works quite well for objects that are further away. But with very close objects the limit is reached at some point: the refractive power of the lens cannot be increased any further, the image remains blurred.

The part of the farsightedness that can be compensated by accommodation is called "latent hyperopia". It decreases with age because the lens loses its elasticity in the course of life and its refractive power decreases.

Symptoms

From adulthood onwards, the poor eyesight increases noticeably in farsighted people. The poor eyesight becomes particularly evident when reading or working on the screen. Affected people need a long distance to be able to recognize anything at all. Reading can also lead to headaches and other symptoms of fatigue such as burning sensation or pain in the eye area.

Mild (low or moderate) farsightedness can affect children and young people as described in the section "What causes farsightedness?" can be compensated for by accommodation. At the same time, however, the accommodation also creates an inward movement of the eyeballs. It can happen that farsighted people whose visual defects are not corrected begin to squint.

If the eyeball is too short (axial hyperopia), the risk of glaucoma (glaucoma) is also increased. This is because the chamber angle through which the aqueous humor formed by the ciliary body leaves the eye is often too narrow in axial hyperopia. The outflow of aqueous humor can be hindered, the pressure in the anterior chamber and thus the risk of glaucoma increases.

To keep the risk of glaucoma low, farsighted people should have regular ophthalmological examinations with a measurement of the intraocular pressure.

Farsightedness in children

If parents or teachers have the impression that a child is cross-eyed or has problems reading and writing, it is highly advisable to see an ophthalmologist. Reading or writing difficulties can sometimes be traced back to physical causes (such as undetected farsightedness). Even if the eyes of young people can initially compensate for their farsightedness themselves without visual aids, glasses or contact lenses are a relief for the eyes at any age.

Furthermore, this is the only way to prevent the risk of developing poor eyesight (amblyopia) with existing farsightedness. If farsightedness that is different in both eyes is not corrected, the affected child prefers to use the better-seeing eye because it does not have to strain it. As a result, less use is made of the poorly seeing eye and its vision can atrophy. The result is poor eyesight that cannot be fully corrected later, even with glasses or contact lenses. An early detection of farsightedness can prevent the development of such poor eyesight (amblyopia) if corrective glasses are prescribed in good time.

When the eyeball grows, farsightedness, especially in small children, can also disappear again, that is to say "grow together".

Early detection and diagnosis

With the help of an eye test, the eyesight can be determined. Such an examination can take place at the ophthalmologist or optician. Those affected have to recognize and describe letters or characters of different sizes with one eye each. The test results can vary depending on the time of day, lighting and individual wellbeing.

As a result, the subjective visual perception is particularly important for the final determination of the required strength of spectacle lenses or contact lenses. Headaches due to unsuitable glasses or lenses can be avoided in advance if this is sufficiently taken into account in the selection.

An eye test examines how well a person can see into the distance (far vision) and up close (near vision). First, with the left eye covered, the right eye is examined once without and once with corrective glass. The other eye is then tested according to the same scheme. It is important to take latent farsightedness into account. This is why it is best to determine the visual acuity of younger farsighted people by turning off the ciliary muscle by administering eye drops (cycloplegia).

When determining the refraction, which is used to determine the required spectacle power, two methods are always used:

1) Objective refraction determination

With objective refraction, the image is automatically adjusted with upstream lenses so that the tested person can see clearly. The values ​​that are measured at this moment are also an indication of the strength of the right glasses or contact lenses.

2) Subjective refraction determination

With the subjective determination of refraction, the individual impression and subjective feeling determine the result. The appropriate strength is determined by holding different lenses in front of the test person's statement. The results of the objective refraction determination can form the basis here. Corrective measures are then made with the lens that best enables close-up vision without impairing distant vision.

© W & B / Möhle Ulrike

Therapy: how can farsightedness be treated?

Farsightedness can be remedied by wearing glasses or contact lenses. For farsighted people, so-called collective lenses with a positive refractive or diopter value are used. The lenses ensure that when looking into the distance, a sharp image is created again in the retinal plane, even without accommodation. From the age of forty, it is also possible to use bifocal contact lenses, which correct both distant and near vision problems.

Eye surgery is not a standard treatment, but under certain conditions it is suitable for farsighted people who do not want to or cannot wear glasses and contact lenses. Like all operations, such an operation is fraught with risks: It can lead to undesirable consequences such as infections or increased sensitivity to glare. Anyone interested in such an operation should seek precise advice from their doctor on the risks and alternatives.

Usually lasers are used for the operation. For example with the LASIK procedure (Laser-Assisted In Situ Keratomileusis). The prerequisites for this are sufficient corneal thickness and a constant diopter value over a long period of time. This means that your eyesight shouldn't have changed significantly in the past few months. Before the operation, the ophthalmologist thoroughly examines the eyes and explains precisely the risks of the operation to the patient.

During the LASIK operation, the doctor first loosens a wafer-thin lamella of the cornea, the so-called flap, with a fine incision and folds it over like a lid. He then removes the cornea with a laser according to a predetermined scheme and then folds the corneal flap back again. Today, LASIK surgery is often performed with a high-precision femtosecond laser.

With very strong farsightedness, it is also possible to insert an artificial lens behind the iris and in front of your own lens in the eye (so-called intraocular contact lens, ICL). This increases the refractive power of your own lens.

In the case of older farsighted people and an increased risk of glaucoma, it is also possible to remove the eye lens and replace it with an artificial lens ("clear lens exchange"), as is the case with cataract surgery. This operation reduces the risk of suddenly developing greatly increased pressure in the eye.

Our expert: Professor Dr. med. Carl-Ludwig Schönfeld

© W & B / Achim Graf

Consulting expert

Professor Dr. med. Carl-Ludwig Schönfeld is a specialist in ophthalmology. He completed his habilitation at the Eye Clinic of the University of Munich, where he worked for many years as a senior physician.As part of his teaching activities, he conducted numerous advanced training courses at home and abroad, in particular at Eastern European universities, in Africa and in Asia.

Since 2007 he has been a partner of Professor Dr. med. Christos Haritoglou and Professor Dr. med. Thomas Klink in the operative group practice at the Herzog Carl Theodor Eye Clinic in Munich. Professor Schönfeld focuses on the treatment of retinal diseases, which is also his scientific interest, and vitreous surgery. The expert also teaches at the Ludwig Maximilians University in Munich, works as an examiner for state medical examinations in the field of ophthalmology and for exams to become a European ophthalmologist (F.E.B.O.).

Important NOTE:
This article contains general information only and should not be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor. Unfortunately, our experts cannot answer individual questions.