What causes hypermetropia and presbyopia
Presbyopia cannot really be stopped or cured, but it can be compensated for. Ways to correct the poor eyesight are glasses, contact lenses or surgery. All of them have advantages and disadvantages, various limitations and possibilities.
Correction through glasses
A classic way of correcting presbyopia are glasses. Those affected have different options to choose from.
Reading glasses: It is the simplest form of correction if there is otherwise no ametropia. As the name suggests, reading glasses are only worn to be able to see up close. In the case of farsightedness or nearsightedness, the respective number of diopters must be added to the reading glasses strength. As a result, it is possible that in myopia with minus two to three diopters, the two visual impairments compensate each other. You can often see at close range without glasses between the ages of 55 and 60. Most older people, however, need or need two glasses: one to see clearly at a distance and one for near vision. In such cases or with astigmatism, multifocal or varifocal glasses are recommended.
Multifocal glasses: A distinction is made between two (bifocal) and three-thickness (trifocal) lenses. The former has two so-called concentration zones, the latter three. These zones make it possible to satisfy multiple vision correction needs with one lens. The middle zone, which is available in addition to the distance and near vision, with the trifocal glasses becomes necessary when the accommodation capacity of the eye has decreased to such an extent that a separate correction is necessary for distances between 50 centimeters and one meter. For example, price tags and sheet music can be read or manual work can be carried out. You can wear the glasses all day and don't have to change them to read or drive. The zones of multifocal glasses that can be recognized by fine separating edges in the lens are arranged in such a way that you automatically look through the appropriate correction area. Because look into the distance, raise your eyes and lower them for objects that are close in front of you. Only when you suddenly lower your whole head, for example when walking up a curb, does your view fall through the “wrong” area. This takes some getting used to, but you should be able to do it within a few days.
Varifocal glasses: With varifocals, the lenses are ground in such a way that the transitions from one correction value to the other are smooth. This means that you can switch from distance to near vision without having to “jump” with multifocal glasses. However, if the view leaves the visual canal, for example if you look to the side, blurring can occur. This also requires some getting used to, as, for example, the whole head has to be turned when looking sideways in order to stay in the correct correction zone. Headaches and dizziness can also occur at the beginning. However, these symptoms should subside after a few weeks.
Correction through contact lenses
Presbyopia can also be corrected using contact lenses. This is an option for sports, for example, or for people who do not feel comfortable with glasses. With this form of correction, it is important that the doctor measures the eyes exactly so that the lenses are correctly positioned. And: Older people often do not tolerate contact lenses as well as the tear film becomes thinner with age and the eyes become dry. This is where eye drops can help. The following options for contact lenses are available for presbyopia:
Bifocal lenses: They work like a bifocal lens - look through the top, focus in the distance, look through the bottom, up close. Trifocal lenses have a medium level of correction "built in". So that such lenses do not shift in the eye, they usually have a small additional weight.
Contact lenses based on the simultaneous principle: Here concentric rings are arranged around the center point, which focus the view at different distances. With this variant, the brain needs a while to get used to the lenses, since several sharp and fuzzy images are created at the same time and it has to filter out the desired image.
Note: Both types of these so-called multifocal lenses can only be used if there is no serious eye disease or astigmatism. The patient has to bear the costs himself.
Contact lenses with monovision principle: It is possible to distribute the correction zones over both eyes. It is usually the case that presbyopia is not equally pronounced in both eyes. One eye is the dominant one, the contact lens for distance vision is placed on this, and the contact lens for near vision on the other. The brain superimposes the two images so that both distant and close objects are in focus. Disadvantage: With this form of correction, spatial vision can be restricted.
Correction through operational measures
If the patient with presbyopia does not want to wear glasses or contact lenses, the poor eyesight can also be operated on and thus improve vision. One possibility is laser therapy, which is used to restore the elasticity of the lens. The therapy is irreversible, very expensive at 800 to over 3,000 euros per eye and there are no long-term scientific results on the consequences.
Alternatively, presbyopia can have an artificial lens inserted. Rigid artificial lenses are made of sturdy plastic with several rings for different sharpness zones. The problem with this genre: In the intermediate area, the view is often not optimal, which makes working on the computer difficult, for example, and can cause reflections (halos) to arise around light sources when driving. Deformable artificial lenses that change their position and thus the refractive power behind the pupil could remedy these disadvantages, but are still in the test phase in this country. The advantage of artificial lenses is also their disadvantage: They can be exchanged. In view of the fact that presbyopia increases with age, at least one further procedure will be necessary.
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