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Eyeglasses
Vision Problems
Contact Lenses
Sunglasses
Eyeglasses
Eyeglasses have come a long way
since the first appearance of a magnifying glass around 1000
BCE. Today, eyeglasses have moved from the realm of vision to
the world of style and fashion. This is good news for those
with vision problems, as they now have great choice when
selecting the eyeglasses that are right for them.
Eyeglasses are the number one vision accessory in use today.
Having said that, contact lenses are becoming increasingly
popular. Even those people who select contact lenses as their
primary vision aid will usually have a pair of eyeglasses on
hand for those times they chose to remove their contacts.
Some people experience complications with eyeglasses. The
usual culprit is a reaction to the frames being worn. This is
most often the result of a reaction to the nickel alloy used
in making the frames. There are now several alternate options
available, including frames made from titanium, gold, silver
or stainless steel. As well, plastics such as polyamide, nylon
and polycarbonate are usually hypoallergenic. A less frequent
problem experienced by those wearing eyeglasses is an allergy
to the nose pads on metal frames. In these cases, PVC or
titanium can be used to manufacture the nose pads. These
products are usually hypoallergenic.
Types of Lenses
High Index Lenses
High Index lenses are ideal for those who have strong
prescriptions, but do not want to wear the "coke bottle"
glasses of the past. These lenses are made with materials that
are lighter in weight and thinner than their regular glass or
plastic counterparts. The term high index is used because the
materials used in making these lenses have a higher index of
refraction. The index of refraction is the speed that light
travels as it passes through the lens material.
Bifocals/Multifocals
Bifocals or multifocals no longer need to have a line through
the middle of the lens. These glasses have come a long way and
special glasses are now available for computer users and for
other unique work situations.
These eyeglasses enable the wearer to see or focus at various
distances through the same lens. There are a variety of
reasons why people need to focus differently at different
distances, but bifocals or multifocals offer an effective
solution.
Near vision correction works by having a small portion
of the lens used specifically for this purpose. This portion
of the lens can be many shapes, including round, rectangular
or half moon. The remaining part of the lens usually provides
vision correction for distance, but can also provide no
correction at all.
Trifocals
These lenses provide three different points of focus, most
often for near, intermediate and far distances.
Progressive lenses
These lenses are often called no-line bifocals. They enable
vision correction at distances that most bifocals do not, at
the same time as providing near vision correction. They are a
near and distance correction lens in one and provide a smooth
transition from seeing at far distances, to intermediate
distances, to close up - and everything in between.
The National Eye Institute (A
Division of the National Institutes of Health) offers
excellent resources about
vision, eye
care and contact lenses. This site is available in
both English and Spanish. The Optometrists Network
provides detailed information for parents about
children and vision care. |
