Sunglasses

The history of
sunglasses
When were sunglasses invented?
The first records of the invention of sunglasses come from the Inuit and the ancient Chinese. In prehistoric times, the Inuit wore flattened "spectacles" made of walrus ivory, consisting of narrow slits through which they could see and keep out the sun's harmful reflected rays. A primitive form of sunglasses originated in China in the 12th century, when plates of smoky quartz were made to protect the eyes from the glare of the sun but had no corrective effect. In the 18th century, James Ayscough began experimenting with tinted lenses in eyeglasses, hoping to improve vision as eyesight declined. He believed that it was possible to correct poor vision by changing the colour of the lenses to a blue or green tint.
However, the sunglasses we know and love today can be traced back to English optician Sam Foster in 1929. Foster developed the first "modern" affordable sunglasses for mass production, which only became possible with the introduction of injection moulding technology. He began selling them on the Atlantic City Boardwalk, and his products soon gained great popularity in America. By the mid to late 1900s, sunglasses were becoming increasingly popular. Politicians, movie stars, and musicians all wore sunglasses as a daily accessory. The science of sunglass technology continued to evolve from then on, as other features of mass production came into play and encouraged the development of anti-reflective, anti-scratch, anti-fog and polarised lenses.
Benefits of
wearing Sunglasses
There is no doubt that besides being a super stylish accessory a pair of sunglasses do provide benefits to our eyes. Some even refer to them as sunscreen for our eyes. Why is this the case?

The main reason for sunglasses is to protect our eyes from ultraviolet light. This mainly stems from the sun’s rays. There are three types of ultraviolet (UV) light or radiation: UV A, UV B and UV C.

UVC is largely absorbed by the ozone layer hence it does not pose much of a threat. UV A and UV B have the protentional to cause our eyes damage. UV A accounts for 95% of the UV radiation reaching the earth yet they are less intense than UV B. However, UV A may cause skin cancer, photoaging and certain types of cataracts. Despite UV B rays being less prevalent than UV A rays they are far more intense especially during summer between 10am and 4pm. UV B rays cause cancer, sunburn and damaged eyes. UV B rays are also exacerbated in the snow hence the need to wear eyeglasses when doing snow related sports.
Due to this it is a widely held view that when purchasing sunglasses, one should purchase 100% UV protected glasses. UV protection is a thin film embedded on sunglasses to block 99% of the sun’s rays. If it is not specified that a pair of sunglasses offer UV ray protection look for ‘UV absorption up to 400nm. This is equivalent to 100% UV absorption. There is a myth that a dark lens indicates UV protection, this not the case. Darker lenses protect against glare.

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What is glare and what is a polarized lens?
Glare-or the scientific name Brewster’s angle- is the light that reflects off flat surfaces such as snow, glass, sand or pavement at a perpendicular angle. It can cause eye irritation, eye fatigue and even restricted vision. To solve this, we people are encouraged to buy polarized lenses. They are horizontally aligned polarizing micro crystals that block all vertical light and protect your eyes from glare. These lenses are often used for water sports, cycling and driving. All dark lenses come with glare protection as it blocks or reduces part of the visible light. The difference between polarized and UV protected lenses is that polarized lenses protect against sunlight we can see but UV protection deals with the invisible part.
Other types of Sunglass lenses:
Photochromic sunglasses:
Glare-or the scientific name Brewster’s angle- is the light that reflects off flat surfaces such as snow, glass, sand or pavement at a perpendicular angle. It can cause eye irritation, eye fatigue and even restricted vision. To solve this, we people are encouraged to buy polarized lenses. They are horizontally aligned polarizing micro crystals that block all vertical light and protect your eyes from glare. These lenses are often used for water sports, cycling and driving. All dark lenses come with glare protection as it blocks or reduces part of the visible light. The difference between polarized and UV protected lenses is that polarized lenses protect against sunlight we can see but UV protection deals with the invisible part.
Gradient Sunglasses:
These are tinted from the top down. The top of the lens is darkest. These aissit in driving as the top of the lens blocks sunlight and the bottom of the lens can be used to see the dashboard.
Double Gradient:
These are lenses where the bottom and the top are darkest while the middle is light. They are great if you want sunglasses that are not too dark but shield your eyes against bright overhead sunlight and light reflecting off sand, water and other reflective surfaces at your feet. Hence, they are great for water sport.
Anti-reflective coating
is a special coating that minimizes glare and reflections off the surface of a lens to get more light through the lens. For sunglasses it is good to have on the backside of your lenses to prevent light from bouncing off the backside of the lens. Without it you may see your own eye reflected in the lens.
Mirror coated lenses
highly reflective coatings applied to the front surface of sunglass lenses to reduce the amount of light entering the eye. This makes them especially beneficial for activities in very bright conditions, such as snow skiing on a sunny day.
Multifocal sunglasses (progressive):
consist of different prescriptions in the same lens. For example, having distance, intermediate and near prescriptions in one pair of sunglasses.
Does size matter?
Yes, it does! Sunglasses frame size should mirror face size ad frame size refers to the fit of the glasses. Therefore, a small face should go with small face size. To find accurately sized glasses look for three consecutive numbers when it comes to sunglasses. The first represents Eye size, the second bridge size and the third temple size.
• As illustrated above eye size refers to the size of each lens, from outside edge to the inside edge of a lens. The typical width is between 40-62mm.

• Bridge size refers the area that hangs on the nose or the distance between the lenes. The typical width of the bridge is 14-24mm.

• The temple size refers to the length of the temple piece. It is also known as the arm piece or earpiece. The typical length is 120-150mm.
Having established the above, one should contemplate the following to ensure the perfect fit.

1. The width of your frames should not be wider than the width of your face at the temples.
2. The top of your frames should be no higher than the line of your eyebrows
3. The lower edge of the frames shouldn’t sit on your cheeks otherwise they will start to rub against your skin and cause irritation.

When buying online a way to ensure that the frames fit your perfectly is to use a ruler then stand in front of the mirror holding the ruler in line with each temple. Thereafter measure the distance from one temple to another in centimetres. The frame size should be +/- 3mm from your measurement.

Generally, a measurement below 129mm is for narrower faces. A medium size face has a width of 130-139mm, and a wide face will have frame width of over 139mm.
Sunglasses lens tints and colour:
Lens colours add to the performance of the lens for different lighting conditions but do not increase UV protection. In other words, they add heightened performance for certain conditions but not overall like UV protection. Furthermore, lens colour provides a different look or accessorize differently and cause your eyes to act differently thus making certain colours more suitable for certain activities as opposed to others.
Grey/ Green Sunglass lenses: this is a neutral colour. It reduces the intensity of light without changing colours. The darker the tint the more it reduces glare and eye strain when one is in a bright environment. This enhances depth perceptions making this tint ideal for where colour is important like driving.
Brown Sunglass lenses: reduce glare and block blue light. They brighten vision on cloudy or overcast days. They also increase contrast and visual acuity. They help most in green and blue background hence they are useful for fishing, baseball and golf.
Yellow/Gold/Amber Sunglass lenses: are great for moderate to low light conditions. These tints make objects appear sharper both indoors and outdoors, but they also create colour distortion. They are perfect for snow-related activities, indoor ball sports, night use and driving in fog.
Rose/Vermilion Sunglass lenses: increase contrast by blocking blue light. They have a reputation for soothing the eyes. They are also fantastic to wear for long periods of time. Furthermore, they offer good visibility while driving and reduce screen glare and eyestrain.
Blue/Purple sunglass lenses: provide stunning and enhanced colour perception. They help you see contours around objects clearly, additionally they offer protection from reflective surfaces like snow. They also work well in foggy and misty weather. An added bonus is that they look amazing on any skin tone.
Sunglass
Lens Material:
Polycarbonate: are best for those who will be moving around. It is light and scratch resistant; it also offers a high level of optical clarity and is 50 times more impact resistant than optical glass.

Optical (Glass): are ground and polished lenes that ensure distortion free vision. They are durable and scratch resistant however when they do crack, they tend to spider which impedes vision. Therefore, making it less attractive for sport.

Acrylic: are inexpensive and ideal for fashion or accessories. They are the least durable and optically clear.

CR 39 Plastics: These are thinner, cheaper and half as light as glass. They are widely used in sunglasses and offer great optical performance even for high prescriptions.

NXT polyurethane: This the best lens as it combines all the benefits of optical glass with all polycarbonate’s performance. These lenses are made of Trivex , an advanced polymer material that make the lenses great for extreme impact resistance, superior optical clarity and also make the lens ultralight weight.

Sunglass
Frame Material :
This is an important aspect when choosing sunglasses. This is because frame material impacts the level of comfort, safety and functionality.

1. Metal Frame: are commonly used in sunglasses. They offer malleability, corrosion resistance and ease of adjustability. This makes it ideal to tailor to many face shapes. They tend to be expensive, yet they are less durable and are not ideal for sports.

2. Nylon Frames: are resistant to stress from temperature fluctuations and are flexible while maintaining the stiffness required for safety. These characteristics make them the best for sports. Additionally, they are less expensive, lightweight and stronger in comparison to traditional frames.

3. Titanium Frames: are durable, scratch resistant and are usually found in more expensive sunglasses.

4. Polycarbonate Frames: These are versatile, tough plastic frames that are impact resistant, durable and rigid. These characteristics make them ideal for sports or for children.

5. Acetate Frames: are type of plastic frame but compared to standard plastic- think acrylic or polyurethane- they are stronger, more flexible and weigh less. They come in a variety of colours and textures. Given that the colour is embedded in the material it tends to maintain their colour.

6. Plastics Frames: These are generally cheaper, thicker and heavier than other frames. They are also more easily dyeable thus there is more scope for artistic designs.
Finally, choosing sunglasses for your face shape:

When choosing sunglasses, you will want to choose the shades that compliment your face shape. The aim is to highlight your best features and the best way to do so is to choose frames that contrast your face slightly. For example, a round face should choose angled frames.

Given that when face shape and frames are linked, they create the perfect look, one needs to decipher what their face shape is. The easiest ways to do so are to look in the mirror then trace your face shape or simply take a photo on your phone and analyse the shape.
Sunglass Face types:
Triangle Face Shape
are characterised by wide, square jawline but they have a narrow forehead thus differentiating them from square faces.
Frame Recommendation: Wider frames are advisable as they help the top of the face look broader. You may also try frames that are heavily accented with colour and details on top. This will add balance to your look. Semi-rimless frames are also advisable.
Frames to Avoid: Anything that brings attention to the bottom part of the face. This means rimless or small sunglasses as well as oversized sunglasses

List of all frame shapes to try for triangle face:
 Cat-eye
 Browline
 Aviator
 Wayfarer
 Rectangular
Sunglass Face types:
Diamond Shape Face:
they are the rarest face shape. They have full cheeks, a narrow forehead and jawline.
Frame Recommendation: Rimless or oval frame with a strong brow line. Given the scarcity of this face shape you may want to use fun and funky frames.
Frames to avoid: Square frames as they make your eyes appear narrower than they are. Oversized frames as they make your face look small or squashed. Lastly, small frames as they make your forehead narrower and cheekbones wider.

List of all frame shapes to try for diamond face:
 Browline
 Cat-eye
 Round/oval
 Aviator
Sunglass Face types
Heart Shape Face:
are widest at the forehead with a narrow chin and high cheekbones. The goal is to accentuate the top of the face and add balance to the width of your face.
Frame Recommendation: Wear round or oval shaped frames. Also, you might consider frames that are a bit wider than your forehead to add more balance to your features. A Rimless frame will soften the angular features. Think wraparound, wayfarer and floral or tortoise patterns.
Frames to avoid: Bottom heavy frames, oversized frames and those with a lot of design elements.

List of all frame shapes to try for heart face:
 Oval and circular
 Rectangular
 Rimless and semi-rimless
 Wayfarers
 Cat-eye
 Aviators
Sunglass Face types
Round Face Shape:
Round Face Shape: This face shape is proportionately equal in width and length. Wide forehead, full cheeks and rounded chin.
Frame Recommendation: Angular frames are especially flattering. Sharp angled frames add extra definition and depth. Think rectangle and wayfarer frames. The benefit if these frames is that they add length to your face. Full-rim and semi-rimless are also worth considering. You may want to try bright colour and prints.
Frames to avoid: Small and round frames as your features will be drowned out.

List of all frame shapes to try for round face:
 Rectangular
 Square
 Cat-eye
 Wayfarer
 Oversized
 Aviators/Navigators
 Geometric
Sunglass Face types
Square Face Shape:
Square Face Shape: They are widest along the jaw- which is usually pronounced- and forehead. They also have strong cheekbones.
Frame Recommendation: Frames that sit high on the nose add length that flatters the face. To draw extra focus to your features, consider dark and rounded rather than angular frames. Round frames soften and add contrast to your angular features. Rimless and semi-rimless are also advisable.
Frames to Avoid: Angular frame

List of all frame shapes to try for square face:
 Round or oval
 Browline
 Cat-eye
 Aviators
Sunglass Face types
Oval Face Shape:
A long-rounded face with higher and slightly wider cheekbones that are narrower toward the forehead as well as a narrow chin.
Frame Recommendation: Square, rectangular, aviators and cat eye frames. Try and be bold with a funky colour, texture or frame shape. You can try almost all frame shapes.
Frames to Avoid: narrow frames and frames with heavy design elements

List of all frame shapes to try for oval face:
 Square
 Rectangle
 Aviator
 Cat-eye
Style of Sunglasses:
Aviator Sunglasses:
Popularised by pilots and arguably Tom Cruise. The features of the frame are clean and simple colours, metal frames and teardrop shaped lenses. Style with a white t-shirt. This is suitable for oval, heart, square and diamond shaped faces.
Butterfly or Cat Eye Sunglasses:
These are generally oversized frames. They serve to cover the face from the sun and can be used to hide a wild night. In a fashion sense they draw attention away from those with larger noses. These are best suited for triangular face shapes.
Rectangle Sunglasses:
are wider than they are all tall. Angular rectangle frames work well on round faces and they have the benefit of adding length to a short face. Oval faces can benefit from rectangular frames with softer edges.
Round/Semi-Rimless Sunglasses:
The round semi rimless, browline clubman is a popular example of this type of frame. The clubman was created in 1947 and for a visual representation think Malcom X. These frames draw attention to the top of your face and add breath to the top part of it. Hence, the best face shape for them are diamond and triangle
Square Sunglasses:
These frames are the best for narrow or a round face as they contrast the face.
Shield Sunglasses:
have a single large lens. They offer protection from the sun as they cover the entire eye. They are great for long day in the sun and badminton. Angular shield frames are good for a round face while rimless shield frames complement a square face.
Wayfarer Sunglasses:
a classic sunglass frame that has been worn since the 1950s. Think of James Dean. They are versatile and timeless and look good on any face shape.
Wrap Sunglasses
are great for athletes or those who want to mimic athletes. Their stream-lined design increases the aerodynamic properties of the face and the lightweight frame feels like you are without sunglasses. The lenses cover most of your eyes thus not allowing UV rays to sneak through the side. This makes them great for snow related activities. Some of the frames are spring loaded which means they help them stay on your face during activities. They are ideal for square shaped faces.
Double bridge sunglasses
found on aviator wireframe style sunglasses. The double bridge adds some extra interest to your eyewear. They are usually found on smaller round frames and oversized rectangular and square shaped sunglasses.