Diopters and farsightedness


In the case of farsightedness, objects that are close by cannot be depicted in focus by the eye.

An eye is farsighted when it has the visual defect that it can no longer focus on things that are close by and can therefore see them well.
Far-sightedness is a visual defect that is often based on the fact that the eyeball is too short and the sharp image therefore only arises behind the retina. Another possible cause is a lens that is too weakly curved.

Correction of farsightedness

The correction is carried out with plus lenses, which, thanks to their special refraction, bring the image onto the retina so that it can be seen and recognized clearly.

Symptoms of farsightedness

Typical symptoms of farsightedness are headache and cramped eye muscles that lead to "tired eyes" leads.
Headaches and tension often occur in the evening or after long work.
In adulthood, it is not uncommon for slight farsightedness to go unnoticed up to around 40 years of age, as the eye compensates for the visual defect through adaptation.
If, however, farsightedness occurs in children at an early age, this must be corrected quickly in order to prevent malformation of the eyes and brain region.
Often, parallel to farsightedness in children, so-called astuteness (Astigmatism, astigmatism) on.

Therapy / correction of farsightedness

The glasses that are used for farsightedness are "Plus glasses“, That means that their values ​​are in the plus area.
On the other hand, glasses for myopia are in the minus range.
The lens for the farsighted eye is ground converging / convex so that it is thicker in the middle than at the edge. Due to the special grinding, the image is brought forward so that it can be focused on the retina instead of being bundled behind the retina as was previously the case with the uncorrected eye.

Farsightedness levels

There are three different levels of farsightedness.
In addition to the slight farsightedness of 0 to 2 diopters, which normally goes unnoticed until the age of about 40, there is the medium farsightedness of 2 to 6 diopters and the strong farsightedness of over 6 to about 20 diopters.
"Diopter" is the unit of the refractive index and is necessary for determining the extent of the visual defect and the strength of the corrective lens.
The stronger the farsightedness, the thicker the necessary glass in the middle and the heavier they are.
However, there are now a large number of special glasses and cuts on the market that allow a very thin material despite high visual impairment.

The values ​​for lenses that correct farsightedness can be found e.g. in the glasses pass.