| Modern
refractive surgery has made it possible to correct myopia, hyperopia
and astigmatism. With multifocal intraocular lenses, we can now overcome
the last obstacle: presbyopia.
Multifocal synthetic lenses, which are implanted into
the eye, provide relief for presbyopia at the same time as for nearsightedness
or for farsightedness. Thus, the goal of multifocal synthetic lenses
is to provide freedom from needing eyeglasses or contact lenses.
How
does a multifocal IOL work?
Multifocal synthetic lenses such as the ReZoom Multifocal lens have several points of refraction, hence
the term “multifocal”. There are two main refractive points,
namely the refractive point for close-up vision and the refractive point
for distance vision. In order to achieve this goal, multifocal synthetic
lenses are made from several individual lenses. Figure 1 shows a multifocal
synthetic lens, which is constructed from several rings with different
refractive powers. Because of the distribution of incoming light to
various refractive points, multifocal intraocular lenses allow focused
vision at all distances, ideally without the need for any eyeglasses.
Figure 1: A multifocal lens. The clearly
recognizable rings represent zones with different refractive powers.
Unfortunately however, this comfort has its price: the distribution
of light to several refractive points results in a certain loss of contrast.
This means that at every point of refraction the image is not seen as
sharply as with eyeglasses for that specific distance (see figure 2),
but therefore eyeglasses are no longer needed.
Figure 2: Photographic simulation of close-up
vision with the eye’s natural lens (left image) and with a multifocal
IOL (right image).
On the left side, the letter board appears focused for close-up vision
but blurry for distance vision. On the right side, the letter board
can be read close-up as well as far away, but the contrast is diminished.
How
does the surgery work?
Multifocal synthetic lens implants are a replacement of the eye’s
natural lens. First, an incision of only 3mm is placed at the periphery
of the cornea, and the eye’s natural lens is aspirated by ultrasound
through this incision. Then the multifocal lens is folded and placed
into the eye. Once in the eye, it unfolds and takes the place of the
eye’s normal lens. This surgery is also performed routinely for
the correction of opaque lenses, the so-called cataract. Hence, this
surgery technique is very reliable and proven.
Typical course
of surgery and postoperative recovery
The implant of a multifocal synthetic lens is an outpatient procedure.
Usually, it is only necessary to anesthetize the eye with eye drops.
Surgery is performed on each eye individually, with an interval of approximately
1 week between operations. On the day of surgery, a bandage is provided
for your eye. Your vision is already improved one day after surgery,
although final stability is only obtained approximately 8 – 12
weeks after surgery.
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