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Bifocal Contacts: A Viable Option
for Presbyopes
Baby boomers have never wanted to grow old gracefully.
Thanks to advances in technology, bifocal and multifocal
contact lenses are a viable option for the current generation
of presbyopes. Patients in their middle years today take
their health care into their own hands. They are more aware
of the alternatives that are available for vision correction
than the previous generations. Many want to maintain their
youthful appearance as long as they can and want to be able
to see and be seen without glasses. This market is ripe
for multifocals since some may already have tried reading
or bifocal glasses or monovision contact lenses and had
difficulty adjusting to them.
Soft and RGP Options
A number of design options exist for both soft and rigid
lens (RGP) correction. All soft bifocal and multifocal designs
are simultaneous vision lenses. That is, they permit light
from both near and distance to enter the pupil at the same
time. Patients must train their brains to select the desired
image and filter out or ignore the unwanted rays of light.
Some designs have the distance power in the center, others,
the near. Some are progressive, gradually changing from
distance to near or near to distance seamlessly, in a manner
similar to multifocal glasses; others are concentric, and
have either distance or near in the middle, surrounded by
one or more rings that contain the correction for the opposite
focal length.
Alternating Vision
Rigid bifocals and multifocals not only encompass the full
range of simultaneous vision designs but are also available
in alternating vision or translating designs. Alternating
vision lenses are designed to move up as the patient looks
down, allowing the near portion of the lens to enter the
pupillary area and enabling the patient to read.
Alternating vision lenses may be concentric, usually with
a central distance zone surrounded by a near ring, or they
may resemble a bifocal or trifocal spectacle lens, with
the reading segment in the lower portion of the lens and
prism ballast added to weight the bottom of the lens and
keep the near zone in a downward position. Some translating
rigid bifocals and trifocals are truncated. Truncation involves
removing a segment of plastic from the lower edge of the
lens, leaving a straight bottom edge. This enables the lid
to help push the near zone of the lens up to the pupil when
the patient looks down to read.
Growing Market
Industry estimates indicate that only three percent of
potential patients are currently wearing some form of presbyopic
contact lens correction even though improved materials and
designs continue to be introduced. You should visit your
eye doctor to determine if bifocal contact lenses are a
viable correction option.
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