As
baby boomers reach middle age, the question looms large:
How to avoid either of two telltale signs of aging -- bifocals
or reading glasses?
Boomers have three contact lens
options for correcting the close-up blurred vision that typically
begins in middle age; a condition referred to as presbyopia.
(One of the three options still calls for reading glasses,
but they can be used discreetly.) The
three options are:
- Bifocal contact lenses Monovision
- Contact lenses for distance
vision with supplementary reading glasses slipped over
the contacts for close work
Bifocal contact lenses
One of the two main categories of bifocal contact lenses
may be suitable for you:
Simultaneous
vision
With simultaneous vision bifocals, you look through both
the reading and distance portions of the lenses all the time.
This means that whenever you look at an object, you see two
images of it. One will be clear (from the portion of the
lens most matched to the distance at which you are observing).
The other will be blurred (from the other portion of the
lens). Your brain learns to ignore the blurred image so that
you see the other clear image.
Translating
Translating bifocals are similar in concept to bifocal
eyeglass lenses. They have a thicker lower edge, which,
when you look down to read, rests on the lower lid. As
your eye turns downward to read, it looks through the reading
portion in the lower part of the lens. In fact, even though
they
"translate," a portion of vision through this
type of bifocal is of the simultaneous type. If
you wear bifocal contact lenses, they will normally perform
optimally in bright conditions. Because bifocal lenses
divide the light into two images, each of which will use
about half of the available light, you may find that, in
dimly lit conditions, seeing is more difficult with bifocal
contacts. Driving at night may present more difficulty,
for example.
Monovision
Monovision is an option in which one eye is fitted
with a lens for seeing things at a distance and the
other eye is fitted for seeing close-up. After a period
of adjustment, the brain switches to the eye that is
giving the clearest image at the time. While
many people successfully use monovision, others find
adapting difficult. Mildly blurred vision, dizziness,
headaches and a feeling of slight imbalance may last
for a few minutes or for several weeks as you adapt.
Generally, the longer these symptoms last, the more
unlikely it is that you will adapt successfully. Approximately
two-thirds of patients eventually adapt to a monovision
correction.
Adjusting
to demanding conditions
If you are new to monovision you may benefit from
avoiding visually demanding situations at first,
and instead to wear their new lenses only in familiar
situations. For example, it may be better to be
a passenger, rather than a driver, in a car. In
fact, you should only drive with monovision correction
if you can pass your driver's license eye examination
while wearing it.
Coping
in special situations
Some people are uncomfortable in situations with
low illumination, such as night driving. If that
is your concern, ask us about prescribing an
additional lens to correct both eyes for distance
for those times when sharp distance vision is
required. An alternative is a pair of glasses
with additional power in the reading eye so that
the combined power of your contacts and the spectacles
match your distance prescription. If
you require very sharp near vision, you might
want to ask about an additional lens to correct
both eyes for close-up work. Or, to occasionally
have the clearest vision for critical tasks,
you may want to request supplemental glasses
to wear over your monovision correction, converting
the distance eye to a reading prescription so
that you can use both eyes at near distance.
Contacts for distance; reading
glasses for near vision
The final option for correcting presbyopia is this: Wear contact
lenses for distance, then slip some reading glasses over them
for close-up work. Perhaps not the perfect answer, this option
enables you to avoid the dreaded bifocal glasses. And that
can still be a definite plus. |