Sunglasses how to choose the best lenses

2/19/2020 Sunglasses: How to Choose The Best Lenses
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Sunglasses: How to Choose The Best
Lenses
govisionusa.com (https://www.govisionusa.com/sunglasses-how-to-choose-the-best-
lenses/) · by Meghana B · January 31, 2020
Sunglasses are not only an indispensable summer fashion accessory, but they are
also essential for protecting your eyes from the harmful sun rays.
Especially in summer, when the opportunities to spend a very long time
outdoors are greater and exposure to reﬂective surfaces (beaches, sea or
meadows) is more likely, the eyes are strongly stressed and need special
attention, like the skin in the sun.
What are Sunglasses?
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The ANSI classifies sunglasses as an “individual protective device” (DPI).
Ophthalmic lenses equipped with selective filters for ultraviolet (UV) rays, in
fact, they have the function of protecting eye structures from the risks of solar
radiation.
For this reason, sunglasses must be manufactured to perfection and meet pre-
established safety and quality standards.
Why Do We Need Sunglasses?
Sunglasses provide essential protection to avoid compromising vision, as they
shield ultraviolet (UV) radiation from the sun and reduce intense brightness,
which is responsible for reduced visibility and various disorders such as eye
irritation, eyelid dermatitis, conjunctivitis, and keratitis.
Ultraviolet rays also trigger excessive production of free radicals, responsible for
aging cells and tissues (including eyes). Over time, this phenomenon can
promote the progressive opacity of the lens (the structure that filters and projects
light on the retina) from which cataract development can be achieved. Blue
light-in the spectrum of the visible, bordering on UV rays-increases the risk of
macular degeneration.
Things you should know about Ultraviolet radiation
The sunglasses are equipped with an anti-UV filter, capable of absorbing
radiation of type A and B (UVA and UVB), which are more harmful to the eye
than those of visible light.
Ultraviolet rays derive largely from the sun and include the portion of the
electromagnetic spectrum with a wavelength of between 100 and 400
nanometers (nm).
UVA (315–400 nm): It is ultraviolet radiation that penetrates deep into the skin,
promotes the release of the melanin from melanocytes and tan.

UVA poses a subtle threat: they are also present on days with overcast and
cloudy skies and, unlike sunburn caused by UVBs, do not create particular
discomfort and their impact can manifest itself even after years.
As for the eye, UVA can help determine the opacity of the crystalline (cataract),
eyelid dermatitis, pterygia, conjunctivitis, and keratitis, while damage to the
retina seems to be limited. The appearance of these issues is directly
proportional to the frequency of exposure. The effect of UVA is reduced by
sunglasses and is hampered by protective clothing and filters to be applied to the
skin.
UVB (280–315 nm): They are potentially more harmful and carcinogenic than
UVA, but they produce a stimulating action the neo synthesis of melanin and
activate the metabolism of vitamin D. As with UVA, exposure to this type of
solar radiation can predispose to the onset of various eye problems.
UVC (100–280 nm): These are the most dangerous radiations; Ortuunaly,
however, this type of solar radiation is shielded from the ozone layer in the
Earth’s atmosphere, so they do not generally reach the soil (most ultraviolet rays
that reach the Earth’s surface are, in fact, UVA and, to a small extent, UVB).
If the eye were exposed to UVCs for too long, there would be problems
concerning mostly and conjunctive.
UV: Factors that influence its threat
In general, the penetration capacity of UV, therefore their “dangerousness”
increases as the wavelength decreases and, consequently, as the frequency
increases.
Another detail not to be underestimated is that UV radiation is more intense:
As the altitude rises (every 1000 meters high, UV levels increase by 10–12%);
When the sun is close to astronomical noon, that is, it reaches the maximum
height for the latitude at which you are;

As the cloudiness decreases.
Other environmental factors influencing UV levels are the ozone layer and the
reflective capacity of the Earth’s surface.
How do Sunglasses work?
An ophthalmic lens works by essentially modifying the divergence of a beam of
radiation; the filters with which they are made alter the energy composition
preventing the passage of certain wavelengths or limiting the energy of them.
Sunglasses lenses are equipped with anti-UV filters that act to change the energy
characteristics of ultraviolet radiation. These filters are sometimes added to UV
protection coatings to block all radiation up to 400 nm.
The treatment does not result in loss of brightness: an absolutely transparent
material can be “filtering” while acting on invisible wavelengths.
It should be known, in fact, that the screen against ultraviolet is not given by the
color, but by the filtering power of the sunglasses, indicated with a number from
0 to 4 and affixed in the form of a mandatory sticker on the lens.
On the other, however, it is obvious that colored sunglasses (grey, brown, green,
etc.) reduce color perception.
Risks for the Eyes
Sunglasses: Consequences of UV rays on the eyes
Conjunctiva
The conjuncture is the thin mucous membrane that covers the anterior surface
of the eyeball (except the cornea) and the inner membrane of the eyelids. This
structure can be affected by conjunctivitis, which can also be induced by
exposure to the sun, especially in conditions of strong reverberation.
Inflammation of the conjunctive involves redness, burning and swelling.
The cornea covers the front of the eye, through which you can catch a glimpse of
the iris and pupil.

Transparent and avascular, this structure represents the first “lens” that light
encounters in its path to the optical pathways. If you do not wear sunglasses, UV
exposure can predispose you to keratitis, which manifests itself with burning,
photophobia and the feeling of sand in your eyes.
Iris
The iris is a thin membrane, of variable color and of an angular shape, visible
from the front through the transparency of the cornea. The lighter this part
(blue, green or gray eyes), the greater the risk of manifesting sensitivity to
sunlight (photophobia).
The cataract resulting from this process is usually age-related, although the
causes may be different. In any case, the probability of the appearance of the
senile form of the disease is directly related to the amount of sunlight to which it
has been exposed over the course of life.
Retina
The retina is a tissue of nervous origin, covering almost the entire inner wall of
the eye and helping to perform the first processing of the visual signal.
This delicate structure contains photoreceptors, lightwave sensitive cells: sticks
and cones. The retina functions, therefore, as a photo transducer, that is, it
captures the light stimuli and converts them into bioelectric signals, which in
turn are sent to the brain through the fibers of the optic nerve.
The retina is susceptible mainly to UVA-induced damage: some scientific
research associates sun exposure with the onset of maculopathy.
In particular, solar radiation demonstrated involvement in the induction or
progression of retinal damage in cystoid macular edema, solar retinopathy (or
epitheliopathy) and age-related macular degeneration.
Eyelids and Eye Contour

The eyelids are movable muscle-cutaneous folds, able to completely cover the
front of the eyeball. Like other ancillary eye formations, they are protective by
external agents and contribute to bulb support; The frequent winking of the
eyelids also allows the continuous distribution of tear film on the eye surface.
The eyelids, as well as the skin of the eye contour, is very thin: from an aesthetic
point of view, the sun promotes the formation of wrinkles and spots. It is not to
be underestimated, then, that exposure not protected by sunglasses can increase
the risk of skin cancers in the periocular area.
Sunglasses: What requirements should they meet?
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All sunglasses must be labeled:
The filter power indication, from zero to 4: to choose sunglasses, keep in mind
that the filter categories are:
(0-1) Category (transparent filter, very clear or clear): the filtering power is
almost nil, the lens alone dims the brightness a little, so it is suitable for closed
rooms and days with little lighting;

(2) Category (average filter): for medium lighting and cloudy days;
(3) Category (dark filter): for general use in full sun;
(4) Category (very dark filter): for strong lighting, high mountain, and
reverberating surfaces.
Instructions for use, cleaning, and maintenance.
The filter power category of a lens does not provide information on the UVA and
UVB protection of sunglasses. The latter is referred to by the acronym “UV”
followed by the maximum frequency of filtered light, expressed in nanometers
(nm). For example, UV 400 means that the lens is treated to absorb all ultraviolet
frequencies up to 400 nm, hence both UVA rays and UVB rays.
The level of protection of these lenses is 99–100%. The acronym “UV” is found
as a sticker on the lens and in the information note that certifies the quality data
of the sunglasses.
The mark refers to the ANSI’s minimum standard of protection, so it is not a
guarantee of eyeglasses quality on its own. In practice, it certifies that the lenses
allow no more than 5% of UV rays to pass through. For this reason, it is also good
to refer to the information manual attached to the sunglasses.
The marking can not be affixed on the lens as a sticker, except the size and shape
of the glasses do not allow it; in that case, it must be shown on the packaging.
Types of Sunglasses

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Camera Sunglasses
Polarized sunglasses
Polarized sunglasses are lenses equipped with polarizing (or polarizing filter) and
sunscreens.
Polarizing filters act on visible radiation, modulating brightness and neutralizing
reflections from smooth, shiny surfaces such as water, sand, snow, grass or
asphalt. In addition to limiting the phenomenon of glare, polarized sunglasses
protect eye structures from UV radiation.
Photochromatic sunglasses
Photochromatic sunglasses have the ability to darken in the sun and lighten in
the dark, best adapting to different lighting conditions.
Degrading sunglasses

Degrading sunglasses are characterized by a progression of hue that allows
modulating the light intensity, making them particularly suitable in the presence
of certain retinal pathologies.
Camera sunglasses
Camera Sunglasses (https://www.govisionusa.com/product-category/hd-video-
recording-sunglasses/)are equipped with a camera to shoot video and
photograph with the touch of a button. These have a built-in HD microphone
and records sounds up to 20ft.
What kind of glasses matches your face?
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Oval shape
The oval face is considered an ideal shape because it has balanced proportions.
To maintain an oval natural balance, select frames that are as wide (or wider) as
the widest part of the face, and are also good walnut-shaped frames that are not
too deep or wide.

Triangular shape with base upwards
With this shape of the face, the upper part of the face is very wide, while the
lower part is very narrow. To reduce the width of the upper face, try the frames
that are spread to the bottom, lightweight or unframed glasses (which have a
lightweight, airy eﬀect).
Oblong form
An oblong face is longer with a pronounced beard line, sometimes a longer nose.
To make an oblong face shorter and more harmonious, try the frames that go
higher in-depth than in the width or low bridge of the glasses to shorten the
nose.
Square shape
A square face has a strong line of beard and a wide forehead that is the width and
length of the same proportions. To make a square face look longer and softer, try
the long frames, the frames that go more into the width than in the depth of the
oval framework of the narrow proportions.
Diamond shape
The diamond shapes of the face are narrow in the eye and beard line and have
pronounced cheekbones that can look high and dramatic. This is the rarest form
of a face. To highlight your eyes and soften your cheekbones, try out frames that
have a pronounced line of eyebrows, spectacles without frames, oval or cat
frames.
Round shape
The round face has a rounded line of equal proportions of length and width, with
no corners. To make the round face longer and narrowest, try the narrow square
frames to lengthen the face, a clear bridge to highlight your eyes, and frames that
are wider than longer, like rectangular shapes.

Triangular shape with base down
This shape of the face has a narrow forehead and spreads towards the cheeks
and the area of the beard. To add width and emphasize the lower upper part of
the head, try the frames that are quite pronounced, whether in color or detail, on
the top half of the frame, and the macho shapes are also recommended.
What are the advantages of Sunglasses?
Improving vision
Sunglasses attenuate the effects of diffuse and often annoying radiation. As a
result, the vision with sunglasses is clear and comfortable, especially in very
bright outdoors. This feature is to be taken into account in the practice of
recreational or outdoor sports activities (fishing, cycling, winter skiing, water
sports, etc.) and in situations where it is necessary to protect yourself from the
very intense sunlight or its reflection (sea, lake, snow, ice, sand, lawn and rivers).
Protect your eyes from UVA and UVB rays with the skin, excessive or
unregulated exposure to sunlight can be harmful to vision. Glasses with
sunglasses limit and prevent the harmful effects of this radiation.
The most exposed to the damage of the sun’s rays are children and the elderly,
for whom it is necessary to choose glasses capable of breaking down both UV
rays, and the so-called “blue light”, less known, but equally dangerous, co-
responsible in determining both the opacity of the lens and maculopathy.
Increase in visual comfort
Uv filter lenses make vision more comfortable in environmental conditions
where brightness is very intense. In sunny weather conditions, the result is a
sharper and less tiring view for the eye. Sunglasses reduce eye fatigue, as sight is
not forced to compensate for reflection and other phenomena resulting from
bright light.
Sunglasses are essential for the well-being of the eyes in the city, high mountain,

sea or, more generally, when practicing outdoor activities, where the reflection
of light is very intense. Just think that the snow can reflect up to 85% of the light
rays, the water 20% and the dry sand of the beach about 10%.
How to Choose the best pair of sunglasses?
Before buying a pair of sunglasses, the first rule not to forget is to always ask the
opinion of your eye doctor. The specialist can indicate the type of lenses that are
best suited for your needs, as well as provide practical and personalized advice
about the correct ways of use and the occasions when it is contraindicated to
wear them.
Details to watch out for in Sunglasses
Lenses with a filtered power of 0 absorb up to 20% of the radiation, so they are
fine when the sky is overcast. 4-filter sunglasses absorb up to 97% of the light
and are great on summer days and when you are at sea or in the mountains.
Those with light eyes (green, blue or gray) absorb more light radiation, so they
should opt for lenses with a more filtering power than those with dark eyes (2 to
4).
When considering the purchase of sunglasses it is always good to take into
account that the frame must be comfortable and compatible with the type of
lenses chosen.
In addition, you should choose according to your needs and the use you intend
to make: there are suitable sunglasses for the city and those most suitable for
driving, for the sea and so on.
The general advice for the purchase of any type of eye care (from glasses to
contact lenses) is to turn to a specialized optical center.
Sunglasses: How to choose a frame that fits your
face?

Frame design
One factor that has a big impact on the purchase of sunglasses is the design of
the frame. In addition to personal aesthetic taste, however, it is good to keep in
mind that the wide models, protect more, also covering the periocular area.
Generally speaking, it is advisable to opt for more covering frames on days of
intense sun, while the less extensive ones may be intended for the conditions of
less radiation.
For sports practice (skiing, running, ﬁshing, etc.) and activities that require
maximum protection (e.g. hiking on a glacier) are indicated models of
wraparound sunglasses.
What are sunglasses made of?
The frames are made from the most varied materials (metal, acetate, wood,
etc.). Again, in addition to aesthetics, the practicality should be considered: in
general, it is better to opt for light and durable sunglasses, which do not bother to
carry them (which, among other things, would discourage its use of habitude).
As for lenses, the choice should be made according to the use to which the
sunglasses are intended: glass glasses are heavier and more delicate, while the
polycarbonate ones are light and easily portable. In the presence of a refractive
vice (myopia, hyperopia, and astigmatism), it is possible to equip the correction
lenses.
Don’t forget to protect children’s eyes from the sun: for them, there are frames
and unbreakable ﬁber lenses.
How to protect your eyes from the sun?

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GoVision Royale
The best strategy to protect your eyes is to avoid direct exposure as much as
possible and always wear sunglasses when outdoors.
Wearing eye sunscreen throughout the year is a good habit. Although the sky is
cloudy, the radiation is widespread and often annoying.
How to clean sunglasses?
To clean the lenses of the sunglasses you can opt for the use of microﬁber cloths
(https://www.buysimplynatural.com/product/100-all-natural-wood-ﬁber-
cleaning-cloth/). These remove dust and moisture without scratching glasses or
leaving halos.
However, avoid using handkerchiefs or shirt sleeves or paper for cleaning
sunglasses because these will damage sunglasses by scratching them.
Conclusion
If sunglasses are among your favorite accessories, they require a minimum of
thought before you go on the purchase.

The best way to ﬁnd the glasses that ﬁt you best is simply to try, so go for it! And
have fun.
govisionusa.com (https://www.govisionusa.com/sunglasses-how-to-choose-the-best-
lenses/) · by Meghana B · January 31, 2020

Sunglasses how to choose the best lenses

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