9
Bifocal IOLs
have been designed to
serve both far and near vision. The
upper section is designed for distant
vision, while the lower section has
a higher refractive power in order
to accommodate near vision (like
reading a book at 30-35 cm).
Nowadays with the everyday use
of computers, there has been an
increasing need for good vision
for an intermediate distance of 50-
60 cm, which is not possible with
bifocal lenses. The answer to this
problem might be a trifocal lens.
Multifocal lenses
have been created
to satisfy the needs for distant, near
and intermediate vision. The body
of the multifocal lens consists of
annular zones with various refractive
powers, in order to accommodate
vision at different distances.
The main disadvantage of these
lenses is the decrease in contrast
sensitivity. Practically this means
greater difficulty to see distant
objects under conditions of poor
lighting as in night driving. Most
patients mention very satisfactory
near and intermediate vision, others
might ask for glasses for near,
depending on their needs.
4
5
Bifocal lenses by
Occulentis. Arrows show
the area for near vision.
Multifocal lens (the rings
can be distinguished
from the center to the
periphery) for distance,
intermediate and near
vision.
especially at night. At
Athens Eye Hospital
the vast majority of
lenses used are aspheric.
