Single-intensity lenses only refract light from a single distance. If both eyes are corrected to the same extent, both eyes can be seen sharply at a distance, e.g. in the distance. If IOLs of different strengths are implanted in the eyes, the so-called monovision is created, which makes it possible to see sharply at two distances.
Conventional spherical intraocular lenses have simple so-called spherical optics, which are not specifically adapted to the patient's eye.
In aspherical IOLs, the properties of light refraction by the cornea are compensated at the lens level in such a way that the image on the retina is as sharp as possible. This improves contrast vision and reduces glare at dusk.
A toric IOL is honed in such a way that the astigmatism of the eye can be corrected. This must be implanted at the right angle so that the light on the retina is focused into a point.
It is known that light with short wavelengths, such as UV light and blue light, is particularly harmful to the retina and accelerates the progression of age-related macular degeneration. This has been proven by several studies. It is therefore assumed that IOLs that absorb UV and blue light can protect the retina.
From around fifty years of age, the eye's natural accommodative capacity decreases, meaning that the eye can no longer focus from far to close and glasses become necessary. The ability to accommodate does not return even after the operation of horror.
There are special artificial lenses that allow you to see near and far with both eyes. Not all eyes are suitable for such so-called multifocal lenses. A clear, regular cornea and an intact retina are required.
In contrast to monofocal lenses, multifocal lenses do not bundle light to a single point, but split it over several points at the same time. This makes a so-called “pseudo-accommodation” possible. In most of these multifocal IOLs, the refraction of light in the central areas of the implant is more for closer distances and those of the periphery more for the distance. Since the pupil gets smaller to see close up, it makes sense. Intact pupil play is therefore a prerequisite for the success of these IOLs.
Depending on the type of implant, the light is distributed differently over the distance, middle distance and proximity. This means that only part of the light from a certain distance is refracted in such a way that a sharp image is created on the retina. This results in a slightly reduced perception of contrast and black letters on a white sheet are perceived as greyish. The multifocal optics of IOL also produce stray light, which can lead to the following phenomena:
These phenomena vary depending on the patient's eye and on the implanted IOL. As a rule, after a few months, it is no longer noticed or suppressed by the brain.
As the name says, the light is distributed over three focal points (near, medium, far). The focus is on proximity and distance. The contrast decreases accordingly, especially in the middle distance. Multifocality is created by concentric rings on the lens surface, which can lead to halos when looking in the dark and can therefore be particularly annoying when driving at dusk. In most cases, these atriums, known as “halos,” are noticed less or not at all after the first three to six months after surgery.
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As with the trifocal lens, the light is also divided over several areas with an eDoF (Extended Depth of Focus) or Comfort lens. In contrast to the trifocal lens, the transitions are mostly seamless, resulting in a type of extended, seamless depth of focus with a focus on medium distance to far. As a result, atriums can be reduced to a minimum. For relaxed close-up work, such as reading newspapers, single-vision glasses are required.
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So-called “instant focus technology” combines a refractive monofocal IOL with a so-called axicon in the center. This axicon works like EDOF optics and enables continuous near and mid-range vision. The peripheral or outer parts of the lens are responsible for viewing into the distance. This enables near, medium and far vision with a minimum of light phenomena (halos).
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Multifocal IOLs can also be combined. This involves correcting both eyes for the distance. In the non-guide eye, a lens is implanted, which also sharply depicts the proximity, and in the dominant guide eye, an IOL is used for the long and medium distance.
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State-of-the-art formulas are used for lens calculation, which are constantly being improved, but an inaccuracy of approximately 0.5 diopters must be calculated. Especially with multifocal IOLs, it is important that the eye's visual defect is corrected as precisely as possible in order to be able to take full advantage of the sophisticated optics of the implant. For this reason, around 20% of our patients require another minor procedure a few months after the procedure
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In general, we have had very good experiences with multifocal lenses, 20-30% of our patients opt for this type of IOLs, although most come to us on recommendation. The satisfaction of our patients is important to us, which is why we try to find out during the preliminary examination whether you are suitable for multifocal lenses or not.
This depends not only on the condition of your eyes but also on your everyday habits and hobbies. People who exercise a lot or spend time outdoors often find glasses annoying and are
Around half of our patients get along very well with their new vision immediately after surgery and feel very well. The other half of the patients must first get used to pseudo-accommodation.
How can I estimate whether I will be satisfied after the operation?
Patients who have already worn multifocal contact lenses before surgery, as well as far-sighted patients get used to the new vision very quickly and are therefore satisfied more quickly.
Patients who have always seen well at a distance and only need reading glasses usually complain after the operation that vision in the vicinity works very well without glasses, but their visual acuity at a distance has slightly worsened.
Short-sighted patients are quickly satisfied with their vision at a distance, although they initially have trouble seeing clearly close up.
