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By: Christine Haran
Many men and women resist buying their first pair of reading glasses. To them,
reading glasses—no matter how stylish—are irrefutable proof that the aging
process is marching on. Fortunately, new alternatives are available to those who
don't like the thought of fishing glasses out of their bag or their pocket each
time they need to read a menu.
Below, Penny A. Asbell, MD, a professor of ophthalmology at Mount Sinai School
of Medicine in New York, discusses why people lose their ability to read
close-up—a condition called presbyopia—and reviews their vision options.
Why does our vision change as we age?
Inside the eye is a lens, and that lens actually changes shape. When we are
young and we're looking into the distance and then close-up, the lens changes
shape so that we can focus and continue to have good vision. What happens as we
age is that lens gets a little stiffer, and it doesn't change shape as easily.
That is when you start reaching for reading glasses, because you need the extra
power that your own lens can't provide anymore. We call that presbyopia, when
you can no longer see close-up.
Who ends up needing reading glasses?
Everybody ends up needing reading glasses. This is universal. There are people
who had great vision their whole life. They said, "I'm eagle eyes. I can see
everything far away." Now they're in their 40s, and they're having trouble
reading, and it's really disturbing to them.
When does presbyopia begin?
Typically, you first become symptomatic in your 40s, requiring a low-plus lens,
usually a +1. And then it moves up to about a +3. So as we age we end up needing
a little bit more over time.
What kind of glasses are available?
They now sell reading glasses in the drugstore. Those work fine for many people.
And for people who already need corrective lens for distance, there are glasses
called progressives that have a different power on the top for distance, and the
bottom power has reading power. They look like normal glasses, but they actually
give you good distance vision and good reading vision. Bifocals are the glasses
where you actually can see the line in the glass. Those work terrifically but in
our youth-oriented culture, people don't like to wear glasses that make them
look old, so to speak.
And now there are contact lenses that act like bifocals that give you distance
and near vision, and some patients do very well with those.
What is monovision?
Monovision is where you correct one eye for distance and the other eye for
reading. Sometimes they call it blended vision because you actually continue to
use both eyes together. It is just that one eye is doing more of the distance
vision, the other one is doing more of the reading vision.
This is something we have done for many years with contact lenses. You cannot do
it with glasses. It's just creates an unbalanced feeling if you have one glass
that is good for distance and one good for reading. But we can also create
monovision with surgical procedures, such as conductive keratoplasty (CK) and
laser surgery.
Does monovision work for everyone?
Monovision works very well for many people. However, in some people, they may
feel a little unbalanced or even have a change in their depth perception. So if
somebody is thinking of monovision, whether it's with contact lenses or
refractive surgery, the best way to decide whether it is for you is to try it
with contact lenses first.
What does the laser surgery involve?
Laser surgery, such as LASIK, has now been around for more than 10 years. When
we use a laser, we change the shape small part of the cornea. If we change the
shape of the cornea, we can change the vision. The laser is used to cut and
remove tissue, so there is a permanent change to the eye.
What is conductive keratoplasty (CK)?
In CK, we use a tiny probe that delivers radiofrequency energy to the part of
the cornea called the stroma, and it shrinks that tissue, kind of like cinching
a belt, to tighten the cornea and make the central part steeper. CK has become
an exciting alternative for people who are presbyopic. It is minimally invasive.
There is no laser. There's no cutting. There's no tissue removed. And the
chances are you'll have excellent vision.
Are there people who are not good candidates for these surgeries?
If you come into laser surgery with significant dry eyes, they may get worse
after the laser procedure. Sometimes patients may experience a glare or halo
after the procedure, especially when driving a car.
When assessing people for either surgery, one of the things I like to find out
from patients is what kind of work they do. If it's somebody who's cutting
diamonds, these surgeries may not be for them. On the other hand, somebody who
does interviewing—half the day they're talking to people, writing notes about
the interview—they may be a perfect candidate for monovision with CK or LASIK.
So it's very important for me to understand how they're using their eyes and
what it is they want to be able to do to find out what's going to be good for
them.
How long does it take to recuperate from these surgeries?
There is some variability in how someone is going to respond, how they're going
to heal and the final result that they're going to have. For CK, there is some
discomfort for at least one or two days afterwards. Pain and discomfort varies,
so it is often hard to predict, but most patients are back to their normal
function within the following week. Recovery from laser surgery is similar.
There is a little less discomfort, but complete visual recovery takes a little
while.
Why do some patients still need glasses after surgery?
One of the things you are going to discuss with your surgeon is what are the
chances that you will need glasses for some activities. There are some patients
who do not get full correction, so they may still need reading glasses for
intensive activities. So they may have good everyday vision for driving a car
around town, reading a menu. But they may want to have reading glasses for their
very best vision for reading. So if they going to read War and Peace, 1,000-page
book, they may want glasses to give them the best vision for both eyes.
Do people ever have to repeat the surgeries?
In general, the results are quite stable, particularly if you are just
correcting moderate reading vision. With age, you may need to increase the
amount of power you need. So if you correct someone for reading vision, and
they're 45, they're going to need more power when they're 55, because aging
continues to change your vision. So people need to realize that they may need to
come back and do a little bit more because their eyes have aged.
Source :
http://www.healthology.com/focus_article.asp?f=eyecare&b=healthology&c=eyecare_glasses&spg=MAI