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Single Vision Stock / Grind
</h1>
<p>
<a href="http://www.evergrow-optical.com/single-vision-lens/" target="_self">Single
vision lenses</a> are those that have the same focal power throughout the lens. They
can be used to treat short-sightedness, far-sightedness or astigmatism.
</p>
<p>
The conventional stock lenses provide sharp view at the center of the lens, with
some distortion in the peripheral areas. The lenses are fitted to the particular wearer
and optimised for clear vision. Stock lenses are available in restricted power range
only and are limited to frame sizes. While these lenses can be ideal for people that
are short-sighted (minus powers), we recommend grind lenses for people that are long-
sighted (especially high plus powers), that result in a thinner and lighter product.
</p>
<p>
Grind lenses are made with advanced optical design technology and are specially
surfaced to the correct thickness for the dimensions of the frame. These lenses provide
sharp view and minimal distortion in the peripheral areas. There are different lens
technologies available to grind single vision lenses. Besides the standard grind
lenses, CR Surfacing offers Digital and Digital Accuracy lens designs, that
take single vision performance to the next level.
</p>
<p>
For general purpose, everyday wear, we recommend using Satin UV Anti-Reflecting
Coating. Our Satin UV Anti-reflective coating is developed to improve vision by
reducing glare, eliminate eyestrain by enhanced visual performance, protect your eye
health by blocking UV rays, and enhance cosmetic appearance by cancelling out
reflections on the lens surface. This coating also helps extend the life of the lenses.
The Satin UV coating consists of layers specially formulated to create a scratch-
resistant, water and dust repellent coat, making the lenses last longer. An ideal
solution for everyday use, no matter the environment.
</p>
<p>
If you spend a lot of time on computers or digital devices, to give your eyes as
much comfort as possible, we recommend to pair these lenses with Satin Blue coating.
CR Surfacing’s special anti-reflective Satin Blue coating filters out harmful blue
light coming from digital surfaces, as well as natural and artificial lights.
Approximately one third of all visible light is blue light, a high-energy light that
has a number of biological effects, including on the eye. Blue light penetrates all the
way to the retina and can damage the light-sensitive cells and can increase the risk of
age-related macular degeneration. Although not all blue light is bad, as it helps boost
alertness, memory and cognitive function, the harmful wavelengths can be filtered out
with Satin Blue coating, providing maximum comfort, enhanced visual performance and
protection for your eyes.
</p>
<h2>
Progressive lenses and the advantages of having them
</h2>
<p>
<a href="http://www.evergrow-optical.com/bifocal-progressive-lens/"
target="_self">Progressive lenses</a> are no-line multifocal eyeglass lenses that look
exactly the same as single vision lenses. In other words, progressive lenses will help
you see clearly at all distances without those annoying (and age-defining)
"bifocal lines" that are visible bifocals and trifocals.
</p>
<p>
Progressive lenses are line-free multifocals that have a seamless progression of
added magnifying power for intermediate and near vision.
</p>
<p>
The power of progressive lenses changes gradually from point to point on the lens
surface, providing the correct lens power for seeing objects clearly at virtually any
distance.
</p>
<p>
Bifocals, on the other hand, have only two lens powers — one for seeing distant
objects clearly and a second power in the lower half of the lens for seeing clearly at
a specified reading distance. The junction between these distinctly different power
zones is defined by a visible "bifocal line" that cuts across the center of
the lens.
</p>
<p>
Progressive lenses sometimes are called "no-line bifocals" because they
don't have this visible bifocal line. They have a significantly more advanced
multifocal design than bifocals or trifocals.
</p>
<p>
Most people start needing multifocal eyeglasses sometime after age 40. This is when
a normal aging change in the eye called presbyopia reduces our ability to see
close objects clearly.
</p>
<p>
Progressive lenses also are the lens of choice for anyone who needs corrective
lenses to see distant objects clearly (due to nearsightedness, farsightedness
and/or astigmatism) and for those who are presbyopic.
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