By Dr. Lana Mohr
Are your arms not quite long enough to read the newspaper or TV Guide
or stock market report? Can you read a license plate from 200 yards
away, but not the instructions on a medicine bottle? Have you been
told you must give up contacts now that you need bifocals?
When people reach 40 to 45, their eyes lose the ability to focus
up close as well as they did before. The medical term for this is
presbyopia. With younger eyes, the lens inside the eye changes its
shape to change focus from distance to close. Looking at something
far away, the eye is at rest. To see up close (reading or computer
distance), the muscles inside the eye must contract, changing the
shape of the lens and changing the eye’s focal point to the
correct distance. Over time, the lens becomes more dense and less
flexible, unable to change shape enough to focus on things up close.
When this first begins, a person may see clearly 20-30 inches away,
but not something right in front of their face. As presbyopia progresses,
a computer monitor 20 inches or more away becomes blurry.
In the very early stages of presbyopia, eyes may just feel strained
and tired after reading, paperwork, or working on the computer. Vision
may be blurry at a distance after sitting at a desk or computer all
day. It may be difficult to read road signs on the way home that were
no trouble to read that morning driving to work.
There are several options to correct presbyotic vision. If there’s
no need for distance vision correction, just wearing reading glasses
may solve the problem. Since things at a distance will be blurry with
the glasses on, this isn’t always the best option. Another option
is one of several different types of bifocal glasses that work whether
or not distance vision correction is needed. If there is no need for
distance correction, the top part of the glasses will have no power.
The bottom part of bifocal lenses will have the prescription needed
for reading. Different visual demands require different corrections
but an eye care professional can help decide which type of bifocal
lens is best for individual vision requirements, depending on type
of work, hobbies or interests. There’s usually a period of adaptation
getting used to bifocal correction. People often have trouble with
steps, for example.
Until recently, there were few good options for contact lens wearers
with presbyopia. Some people wore reading glasses over contact lenses
for close work. Some were fit using single vision contact lenses in
a “monovision” style of correction accomplished by correcting
one eye to see clearly at a distance and the other to see clearly
up close.
Many people wear these types of lenses successfully. However, many
cannot adapt to the difference between the two eyes and the accompanying
loss of depth perception.
Good bifocal contact lenses are available for patients who wear contact
lenses or glasses, or those who have never worn either, but now need
close vision correction.
Disposable soft contact lenses that are progressive addition bifocals
are the most recent addition and have proven very successful. The
power of these lenses gradually changes from near correction to distance
correction. This allows clear vision at many different focus distances,
including far (road signs), intermediate (computer screen), and near
(newspaper or book). Contact lenses reduce the adaptation problems
of bifocal glasses, because they don’t have the distortion of
spectacle lenses.
For astigmatism as well as presbyopia, there are still contact lens
options available. A monovision fit may be successful with toric contact
lenses. There is also a rigid gas permeable contact lens available
in bifocal form that can be fit as successfully as soft lenses. A
similar progressive bifocal addition is achieved, with clear vision
at all distances.
For anyone who needs bifocals, and thought reading glasses were the
only option; it’s time to see an eye care professional to find
out what is available. It may be possible to have clear vision with
no glasses at all!
For more information, contact Dr. Mohr at Vienna Eye Clinic,
1600 Grand Central Avenue, 304-295-8561.
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