The article "Contact Lenses And Why We Wear Them" is about fitness, it was released by J Schipper.
We wear contact lenses mainly because we are vain.
But, they come in handy for any kind of sports, human being even wear
them while swimming although you have to wtach they don't float
out.
The Inventor of the contact lens concept was Leonardo da Vinci
in 1508,who sketched and described several forms of contact
lenses.
Hard contact lenses
Hard contact lenses are manufactured from a rigid material,
PolyMethylMethacrylate (PMMA). This substance is also combined
with other plastics to inrcease the oxygen permeability.
Visual
acuity is fantastic.
In 1632 Rene Descartes of France suggests the first hard contact
lens, which idea was actually developed in 1801 by Thomas Young;
resulting in a quarter-inch-long, water-filled glass tube, the
outer end having a microscopic lens,and he is the first user.
In 1887 a German Glassblower, F.E. Muller of
Wiesbaden,fabricates the first piece of glass acting as a
contact lens which could be seen through seen through and
tolerated.
Soft daily wear lenses have the main adavntage that they allow
the eyes to be oxygenated through the lens.
They're also fast to adapt to and difficult to lose.
You can get
them in all kinds of coolurs. Fantastic for wearing in sport
activities.
Not a panacea for all vision troubles and they have to be
thoroughly cleaned. Maximum lifespan 1 year.
In 1936 William Feinbloom, a New York optometrist, manufactures
the first American- made plastic contact lenses. These were
still hard lenses.
The first soft, water-absorbing plastic lenses were developed in
1960 by Otto Wichterle and Drahoslav Lim .
Disposable lenses
1.Extended-wear disposable
Soft lesnes that you are able to wear for an extended period of
time, up to six nights, and then you can throw them away.
They
hardly require any cleaning and have virtually no chance of
causing eye infection if user instructions are followed...
You can get them tinted and as bifocals.
Your Vision may not be
as sharp as with other lenses and they do not correct all vision
problems.
More difficult to handle.
2.
Planned soft daily replacement lenses
Soft daily wear lenses that you replace on a planned schedule,
either every two weeks, monthly or quarterly. Require thorough
cleaning and disinfection.
all vision troubles. Not fast to
handle.
Colored lenses
There are 4 types of colored contact lenses:
visible tints, tints to enhance, color opaque tints and tints
that filter light Most of these colored contact lenses are
available in plano form (without visual correction), as well as
for astigmatism, who need bifocal correction, or who want a
disposable or frequent replacement lens.
Astigmatic lenses (toric) were first introduced in 1978 and
approved for distribution in the United States.
These lenses contain both a spherical and cylinder component to
correct prescriptions which have astigmatism. Lenses may be
thicker in one meridian or have modified thickness profiles to
enable the lens to maintain the crorect orientation on the eye.
Bifocal contacts became available in 1982 for commercial
distribution.
There are a variety of designs in bifocals, essentially all
trying to provide a transition or reading zone for use at near
distances. The different designs include; + aspheric multifocal
- + simultaneous vision concentric - has either a central near
or distance zone with surrounding zone of opposite type to
centre (eg, centre near,distance surround) +
diffraction/holographic - based on diffraction grating
principles.
Eye exercises There seems to be a natural alternative to
eyeglasses, contacts, intacs, and even Lasik surgery, which is a
series of eye muscle exercises over a period of 30 days that
supposedly corrects your vision to quite an extent.
The validity of that method of vision correction has not been
fully proven.
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