| The primary aim of spectacles is to help enhance
a person's vision and aid the correction of visual impairments,
if any, though the recent times have seen a swelling list of
its functions. To this end, corrective lenses are used. These
lenses come with different specifications corresponding to individual
requirements. Lens is dubbed as the all inclusive medicine for
optical sickness. it varies for different optical needs. For
corrective purposes,specific optical requirements are to be
met otherwise plain lenses can be used. |
| Lenses can be clear (indoor) or dark (outdoor)
or photochromatic lenses that darken when exposed to sun. These
lens specifications can be integrated into plastic, glass etc.
The lenses can be embodied in different materials like glasses,
plastics and poly carbonate materials. |
|
| Glasses |
| Are known for their scratch resistance and hardness
prowess, but are easily breakable and guarantees very Iittle
protection from Ultra Violet rays. The glasses are also too
heavy for comfort. |
| |
| plastic |
| The plastic lens, on the other hand, is lighter
shatter resistant and ensures greater protection from UV rays
though at the cost of inherent softness and scratch proneness. |
| |
| Poly Carbonate |
| The Poly Carbonate, a synthetic plastic material,
is known for its high impact resistance, almost bullet proof
resistant at point blank range. The impact resistance makes
this lens highly preferred for sports wear, children's wear
and safety wear. Polycarbonate lenses are used for astronaut
helmet shields and space shuttle windshields. Weighing only
35 percent of the plastic lens, it is one of the lightest ophthalmic
materials. The in built protection properties offer 100% ultra
violet blocking to about 400 nanometers. |
| |
| Airwear |
| Airwear is one of the new additions to the optical
family. A material made from pure polycarbonate resin, Airwear
is 43% lighter than ordinary plastics. The lightness does not
in any way compromise on the impact resistance. Airwear lenses
can also be made 35% thinner and 45% flatter than ordinary plastic
lenses with no loss in optical performance. Airwear lenses provide
anti reflective coating and promises 100% UV protection. To
top it all, these perks can be availed of at a throwaway price. |
| |
| Aspheric |
| Aspheric lenses have arrived and they are here
to stay, These models have emerged as a credible alternative
to the traditional spherical lenses. With its advent, optical
distortions are a thing of the past. As aspheric lenses do not
bulge out of the frame as much as regular lenses, they are much
more appealing to eyes. The fact that they lessen the magnification
or minification of eyes, a problem for patients requiring strong
correction, draw customers to this variety. Most lens designs
can now be ordered in aspheric form. |
| |
| High index |
| High index lenses have been introduced as a replacement
for the cumbersome thick edged lenses. These are a variety of
plastic materials that bend light more than conventional plastic.
As a result, the high index lenses are lighter, thinner and
flatter. . Highindex materials are available in hard resin plastic
and extra impact resistant polycarbonate material. |
| |
| Progressive |
| Progressive lenses offer greater visual correction
than ordinary reading glasses and bifocals. These lenses have
taken optical assistance closer to natural vision than ever
before. They pull off an amazing feat by allowing good vision
near, far and everywhere in between without annoying, distracting
lines. This is why they are sometimes called no-line bifocals.
Progressives provide a smooth transition from distance through
intermediate to near, with all the in-between corrections included
as well. This continuum of lens power provides a natural range
of vision for patients. Unlike other lenses, progressives provide
quality vision in the periphery. Introduction of compact lenses
has added that dash of fashion to the exquisite line up. Progressive
lens has, today, evolved to be the best product for those above
40, principally because the age group depends on glasses for
all the practical needs of daily life. Progressives can double
up as reading glasses as well as bifocals or trifocals, with
enhanced clarity as the add on. Varilux Comfort, Varilux Panamic,
Nikon Presio, Kodak, Kodak Precise, Kodak Concise are some of
the major brands in this category. Nikon Web Lens, which offer
a much large usable area for reading and computer work,is also
a popular option today. |
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