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.
| 