When does presbyopia begin?
The refractive power of the eye decreases continuously in the course of life. Presbyopia is the weakness of vision resulting from a reduction in the elasticity of the lens. From the age of 40 onwards, the reduction in elasticity manifests itself as visual impairment: patients are suddenly no longer able to see close objects clearly.
From this age, the visual impairment also increases rapidly. Up to the age of 55 it increases more and more rapidly, then less rapidly. Here too, however, it must be remembered that the values are variable for each individual and the symptoms of presbyopia do not occur in everyone of the same age.
Symptoms
Presbyopia manifests itself mainly in the fact that the affected patients have more and more difficulties with the .
Diagnosis of presbyopia
Presbyopia is usually diagnosed by the symptoms expressed by the patient at the time of the surgery. Presbyopia can be diagnosed at the optician by means of normal vision tests. The optician first has the patient read something from a newspaper or a book.
The posture that a patient with presbyopia adopts already provides some important clues about the condition: He stretches his arms as far away from the body as possible, while at the same time he pushes his head back. This increases the distance between the eye and the reading. After this orienting assessment, the optician determines the visual acuity by means of visual charts and lenses of different strengths. This works in exactly the same way as a normal eye test at the optician: the patient is put on test glasses and is asked to read letters aloud from a certain distance. As soon as he can no longer read something, the optician changes the lenses until the
By how many dioptres does the refractive power of the eyes deteriorate with presbyopia?
By how many dioptres the refractive power changes with presbyopia cannot be said in general. Rather, it is an individual value that varies from patient to patient. Presbyopia becomes symptomatic at 40 years of age.
In the beginning, an additional dioptre is usually sufficient to increase the refractive power. In the course of time, however, the elasticity of the lens decreases more and more and also more rapidly. From the age of 40 onwards, the elasticity of the lens decreases exponentially. This means that already at the age of 50, the patient may need 2 additional diopters of refractive power in order to see sharply in the vicinity. However, these values must be determined individually by the ophthalmologist or optician, as they can deviate considerably from these guide values.
Therapy of presbyopia
Presbyopia can only be treated with reading glasses. The lenses of reading glasses are so-called convergent lenses. They are therefore convex on at least one side, sometimes on both sides.
Outwardly convex lenses bundle the incoming light rays. Thus, they help the patient with presbyopia to compensate for the lens’ inability to deflect. These lenses bundle the rays of light even before they reach the lens of the eye.
So they help the “decrepit” lens to see close up sharply. Not so long ago, laser treatment for presbyopia, as has been possible for some time for other disorders of accommodation, was not successful, since in presbyopia a decrease in the elasticity of the lens is the cause of the eye’s diminishing ability to focus at close range. However, in the meantime, patients with presbyopia are also treated with laser procedures in Germany.
Most of these are still studies in which experience is to be gathered and long-term results made available, so that the current state of knowledge on a national level does not yet allow any statement to be made about the long-term success of laser surgery for presbyopia. . As a rule, the therapy of choice for presbyopia is reading glasses.
These are glasses with converging lenses that compensate as well as possible for the lack of accommodation of the eye lens due to a loss of elasticity. However, contact lenses are also a possibility to remedy the loss of vision. Patients who were previously normal-sighted as well as those who were previously farsighted or even short-sighted can counteract presbyopia with contact lenses.
In this case, the required dioptric values must be calculated specifically in each case. Otherwise, the same applies to the wearing of contact lenses in presbyopia as to all other accommodation disorders: it is important to find the right lens and to maintain hygienic handling so that wearing it remains comfortable and does not damage the eye. The contact lenses must be re-fitted from time to time as presbyopia progresses, when the person concerned notices that he or she has difficulty seeing close up again.
However, this does not happen quickly, but usually rather slowly, so that a new adjustment every (few) years is often sufficient. As far as the choice between hard and soft contact lenses is concerned, this is left to the person concerned. In the case of normal presbyopia, both types of contact lenses can help, so it is a personal decision which contact lens is more suitable and more comfortable.
If you suffer from presbyopia but do not want to wear glasses, you can have contact lenses made by an optician. These contact lenses differ from conventional contact lenses in that they must enable the reader to see clearly both at a distance and close up. They must therefore fulfil the same conditions as progressive lenses.
The most commonly used model are so-called monovision lenses. With this lens system, one eye is corrected for distance and the other for near vision. This sounds irritating at first, but the brain is only able to adjust to near vision or television.
Other types of lenses are based on the system of progressive lenses: The upper part of the lens is designed for near vision, the lower part for far vision. The important thing with this lens system is that the lenses can glide easily on the eye and that their position does not change. In addition, you first have to get used to using these lenses.
You should discuss which lenses are best suited to you with your ophthalmologist or optician. A lens implant is an artificial lens that can be inserted into the patient’s eye in the event of clouding of the lens or gross defective vision (caused by the lens). There is the possibility to remove the old lens.
This is the case with cloudy lenses. In the case of a visual impairment, the old lens can also be left in the eye. Then the new one is inserted additionally.
In case of presbyopia, multifocal lenses are recommended. These lenses have two focal lengths: One for near vision, the other for far vision. They enable the patient to see at a distance.
There are also so-called accommodating intraocular lenses. These mimic the refraction of the eye’s lens, thus replacing the refractive power of the eye’s own lens. There are also so-called accommodating intraocular lenses. These mimic the refraction of the lens of the eye, and thus also replace the
