Bifocals & Trifocals
Are your "arms getting too short".? In other words, are you holding your
books and newspapers at arms length so that you can read? The medical term for
this condition is presbyopia. Most likely you are over 40 years of age. Bifocal
or trifocal lenses will enable you to see at a distance and enable you to read
with just one pair of glasses. If your eyes
are 20/20 for distance, but you cannot read a newspaper without holding it at
arms length, you have the option of just purchasing reading glasses. There are
some drawbacks to reading glasses. Please refer to our reading glasses page to
see the pros and cons.
Bifocals allow the patient to see through two different prescriptions, one
for distance and one for close. Bifocals give you two points of focus. It is not
only people over 40 that need bifocals. Certain conditions can cause younger
people to need help read at the close range. Over convergence is one of the
conditions. This is condition where the eyes work too hard to see close-up.
Your near vision correction is situated just below your eyelid, this makes
the transition between your distance correction and your near correction easier.
Of course, this measurement depends on your occupation and lifestyle. Your
bifocal should be set lower if you are wearing your glasses for golfing. Your
optician will take this into consideration when measuring your bifocal height.
It is very important that you inform your optician as to what you expect out of
Polycarbonate lenses are thinner and lighter in weight than plastic lenses.
Polycarbonate lenses are also the most impact resistant lenses you can buy. It
is an excellent lens to use for sports, industrial safety and of course for
children. Although polycarbonate is a soft material it is flexible and gives
slightly under pressure without breaking. Polycarbonate is the material that is
used in "bulletproof" windshields. All polycarbonate lenses offer ultraviolet
protection and scratch resistance. Keep in mind scratch resistance does not mean
scratch proof, your lenses can still scratch but are less likely to. It is very
important that you follow the manufacturer's instruction on the proper care of
your polycarbonate lenses.
When buying polycarbonate lenses for sport use keep in mind that you should
buy a sport frame and not a dress frame. When playing basketball, baseball etc.,
the frame is as important as the lenses. These frames are made so that they hold
up to the impact of a ball.
Polycarbonate lenses are an excellent choice of lens for safety glasses.
However these lenses should be in an ANSI approved safety frame. Our
opticians can show you what frames are