The lenses used in sunglasses are very important for providing proper protection for the eyes. With the advancements in the glass manufacturing technology, different types of lenses are used in glasses. Each and every type caters to different needs. You have to know about the lenses to choose the glass for your purpose.

Lenses are made of plastic or glass. Plastic lenses are light weight made of plastic material that can be tinted with different colors of your choice. They block 80% of UV rays thus providing good protection from the sun. Glass lenses are more prone to scratches but they have excellent inherent optical quality.

Polycarbonate lenses are widely used in sunglasses these days. They provide 100% sun blocking. They are very light and they don’t shatter very easily. Polycarbonate lenses are perfect for sporty glasses and children sunglasses as they are scratch resistant.

High index lenses are made of high index plastic material. They are widely used for cosmetic purposes as they are very thin. Like polycarbonate lenses, the high index lenses provide 100% protection from the harmful rays of the sun. High index lenses must have anti reflective coating because the surface reflections increase with the increase in the index of the lens.

Aspheric lenses are best suitable for people who need to wear high prescription glasses. In this type of lens the thickness of the lens is evenly distributed compared to the conventional lenses. Thus they provide very clear vision and also give you a stylish look. For light weight glasses, aspheric lenses are made with the high index material.

Photochromic lenses have the property to control the light entering the eye irrespective of the conditions prevailing outside. When you alternate between indoor and outdoor you have to choose these lenses to reduce the strain on the pupil of the eyes.

Polarized lenses are perfect for an outdoor aficionado. They greatly reduce the glare by canceling the rays due to reflection from the flat surface. These lenses can be used when you are engaged in driving, golfing, skiing, and so on.

Any glass must provide you protection from the harmful UVA and UVB rays of the sun. When you go out your eyes are exposed to the hard sun. So ensure that your lenses have proper UV coating. If your lens is made of polycarbonate or high index plastic, then you need not worry about UV protection as these materials inherently block the sun.

When you want your conventional prescription glasses to look thin and light weight you may consider the use of aspheric lenses or high index plastic lenses. Use of smaller frames may also add to the style.

Scratch resistant coating (SRC) is essential for all lenses to prevent the lenses from getting scratches very often. Polycarbonate and high index lenses come with this SRC coating by default.

Anti reflective coating (ARC) is essential for certain type of lenses like high index plastic to reduce the reflective rays. Glasses with this coating eliminated glare caused during driving in the night and staring at the computer. But glasses that have this ARC are prone to scratch and hence ARC and SRC are mutually exclusive. You cannot have both coatings on the same lens.

To improve the look and to see the world in your favorite color, you can add tints to your lenses. Many adults are now tinting their lenses with their favorite colors. Tints can be effectively applied to plastic lenses. The tints will be absorbed uniformly in plastic lenses. Glass lenses cannot be tinted uniformly and are more difficult to tint. High index plastic lenses are easier to tint than polycarbonate lenses. Lenses that have coatings such as ARC and SRC cannot be tinted as the color will not apply uniformly on the coating. If you want to tint, then you must remove the coatings, tint the lens and then reapply the coating. Tints may add style to your glass but you must ensure that your lenses are provided UV coating to protect your eyes. More than a fashion eyewear, the glass you wear must provide clear vision and proper protection for your eyes.

Author : Aakash Shah

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With the advancements in the lens making technology lenses that are lighter in weight are very common these days. The glass lenses were heavy and they have the problem of shattering. The plastic lenses were then introduced as they are shatter proof. The optical quality of plastic lenses was also good.

People who wear prescription glasses for vision correction used glass lenses. The vision correction is obtained by bending the light rays to the required extent. This bending depends on the index of refraction (IOR) of the lenses. To bend the rays, higher IOR is needed and the glass lenses were thick enough to bend the rays. But people wearing thick correction glasses started feeling being pushed out of the fashion world.

Then plastic lenses were used as corrective lenses but it was suitable for weak prescription. For a strong prescription thicker lenses were only used to reach a high index of refraction. Depending on the eyesight problem such as myopia or hypermetropia the lenses were thick either in the middle or at the edges. These people were waiting to wear the trendy flat thin glasses that can correct their vision too. The high index plastic material was used to make lenses keeping the thirst of these people in mind.

High index plastic lenses have a higher index of refraction and hence lesser material is sufficient to reach the required bending of light rays. The curves in the lenses were flat and they provide corrective vision.

The index refers to the amount of bending achieved. This can range anywhere from 1.50 to 1.74. The high index lenses with 1.74 IOR are very flat, very thin and very trendy. These lenses include the current anti reflective treatments to reflect off excess light.

These high index 1.74 lenses are perfect for fashion conscious people who want to be at the pinnacle of fashion. It is for people who want to get rid of their thick corrective glasses which hide the natural beauty of their eyes. These glasses can be used for even strong prescriptions.

The curves of high index 1.74 lenses are flat and due to the extremely flat curves off-axis vision may be blurred. To eliminate this problem aspheric lens technology is incorporated into these lenses. These extremely flat, thin light weight high index 1.74 lenses are sure to add a touch of style to your face but they cost more and they are worth it.

Author: Aakash Shah

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• The first of them are the Single Vision Lens which is mainly characterized with having the same power from the top to the bottom of the lens. People suffering from astigmatism, presbyopia and myopia can go for the use of these lenses in order to correct these vision problems. Astigmatism is a disease when enough light does not reflect on your retina and thus images are visualized distortedly.
•  Then comes the bifocal lenses which are mainly used to correct the problem of presbyopia. This disorder happens when people suffer problems of nearsightedness. This is a vision disorder which usually tends to arise after 40 years of age. When a person is diagnosed with presbyopia it is difficult for them to focus on close objects. This is when one can take the help of bifocals. It helps you to see distant objects from the top of the lens and through the bottom portion of the lens you can correct your close vision. It should be always kept in mind that people with presbyopia has to accommodate both types of focal view on their lenses.
• The third type of lenses is the trifocal lenses. These lenses have a unique feature of three focal points and are very similar to the bifocal lenses. The three focal points include the top of the lens which helps to see the distant objects, the lower part of the lens which helps in seeing the near objects and the middle part which provides the intermediate vision.
• The fourth types of lens available in the market are the multifocal lenses. These lenses also have more than one point of focus. The bifocal lenses and the trifocal lenses are types of multifocal lenses.

The other types of lenses available are the computer lenses which are specially designed to protect your eyes from harmful effect of using computers for prolonged hours. These lenses help you in viewing the computer screen and the text on the computer screen for a long time. Another type of lens available are the Double Bifocal lenses which are usually recommended to the pilots, electricians and other professionals who have to work at a close vision overhead.

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The different types of lenses are:

• Single vision lens which has the same optical correction over the entire area.
• Bifocal lenses are lenses in which the upper potion is generally for distant vision and the lower portion is for near vision. But there is a segment line between the two.
• A trifocal lens is similar to a bifocal lens. The only exception is that there are two segment lines dividing the three different correcting segments.
• Progressive lenses provide a smooth transition from distance correction to near correction eliminating the lines in between enabling a clear intermediate vision.

The most common shape of corrective lenses is ophthalmic or convex-concave. These lenses have the same radius from the back and the front. The difference in the curvature between the front and the back of the lens leads to the corrective nature of these lenses. The bifocals and the trifocals are more complex lens shape, whereas the progressive lenses eliminate the line which is there in the bifocals and the trifocals. The base curve can be changed in order to give the best optic and the cosmetic characteristics across the entire lens.

The greatest cosmetic effect that has come up in the recent years is that of reduction in lens thickness. This results in the increase in material density. The lenses are made from plastics, polycarbonates and high index plastics called the polyurethanes. The lenses can have a scratch resistant coating, an anti glare coating and a coating for protection from ultraviolet rays of the sun.

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With the great advancements in the glass manufacture technology lenses are now made using different materials. Thin lenses are now manufactured using high index plastic material. They have good optical quality and they are of light weight compared to the conventional glass and plastic lenses. The prescription lens requires two properties – the refractive index of the lens and the curvature. When the lens has a higher refractive index, it can bend more light and thus curvature can be minimum leading to a thin lens.

High index lenses are now made using glass or plastic depending on the needs. When the material has high index of refraction, it will be dense and hence lesser material is used in making lens leading to a thinner one. The higher the refractive index of the material, the thinner is the lens made out of it.

People who suffer from myopia mostly use high index lenses for their eyeglass. High index lenses have great advantages for people who wear minus power. The thinning in these types of lenses is uniform and hence gives you a trendy look. For people who have power in the plus region, the thinning of lenses is at the center and it will not be visible. To avoid this problem, aspheric lenses are used. Aspheric lenses are mostly made of high index material and they serve the cosmetic purpose. They also give clear vision which is the main purpose of wearing the eyeglass.

The high index lenses have certain advantages and disadvantages over conventional lenses. On the positive side, these lenses are very flat and thin, giving the wearer the look of an elegant chic. They are also shatter proof and are robust. They can be curved and fitted to frames to give a trendy look. On the negative side, the eyeglasses that use high index lenses are expensive. A separate scratch resistant coating is to be given on the lenses to prevent scratches.

The new advancement in the lens manufacture technology is the use of ultra high index material. These materials provide the ability to manufacture very thin and flat prescription lenses for people who wish to be at the height of fashion. People with higher prescriptions like +/-10.00D can make use of ultra high index lenses for a very thin and flat eyeglass. The cost of the lenses increases with the decrease in their thickness. Thinner and flatter lenses are made out of high index material as these lenses have flat front curves. The aspheric curves deployed in these lenses provide distortion free clear vision with flat and thin structure.

We at Status Eye Care , Mumbai , India are expert in Dispensing Ultra Thin Hi-Index Lenses. Email us at info@statuseyecare.com or Contact us at +919322679910. We will be glad to assist you with your queries regarding Hi-Index Lenses.

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To achieve this fashionable look, you may use high index plastic lenses in your eyeglass. These lenses will have a higher index of refraction. The conventional prescription lenses are determined by the index of refraction and the curvature of the lens. The index of refraction refers to the ability of the lens material to bend the light ray. If the rays are bent by the lens, then curvature will be less. When the curvature is less, thin lenses can be made. Since high index plastic lenses bend light rays, their curvature is less and hence they can be made thin.

High index lenses are available with different indices as 1.70, 1.66, 1.60 and so on. When the number is large, the lens will be thin. Their tensile strength is also high and they can be used in drill mounted eyeglasses.

Every coin has two sides. They are certain disadvantages with the high index lenses. When the index is high more and more light is reflected off the surfaces. This leads to the decrease in the amount of light that is transmitted to the lenses. An ordinary plastic lens whose index is 1.498 reflects 8% of the light and allows the rest to pass through the lens. A high index lens whose index is 1.70 reflects 13.6% thus offering more resistance to the light that is transmitted through the lens.

Lenses that are made up of high index plastic tend to cause dispersion of light. When white light is passed through a high index lens, then it will break into its component colors. Due to this property you may find a color hue around certain images when you use eyeglasses made of high index plastic. This phenomenon is called chromatic aberration. This color hue tends to increase as you move your eyeballs away from the center of the lens. This effect can be avoided by the use of frames which are smaller in size. You will need one day to get your eyes adapted to eyeglasses with high index lenses.

Apart from minor flaws, the high index lenses are sure to offer you a trendy look. Seek the advise from your optician to carefully choose the index of the lens for a clear vision.

We at Status Eye Care , Mumbai , India are expert in Dispensing Ultra Thin Hi-Index Lenses. Email us at info@statuseyecare.com or Contact us at +919322679910. We will be glad to assist you with your queries regarding Hi-Index Lenses.

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The eyesight problem is corrected by eyeglasses by bending the light that is incident on them. For higher prescriptions the light has to be bent more. Thick conventional glasses were used for bending. But the high index plastic material is dense and lesser amount of material is enough for achieving the required bending. Thus eyeglasses made with high index plastic lenses are light in weight, extremely flat and ultra thin.

To correct myopia, the conventional glasses were thick at the edges. Thick frames are to be used to match the thickness at the edges. When you look at the eyes of people wearing such types of glasses, the eyes will look small.

To correct hypermetropia, the conventional lenses were thick at the middle. The eyes will look large for us. The glasses will also be heavy and uncomfortable to wear.

Each lens differs with its index of refraction which specifies the amount of light it can bend. This is a ratio of the speed of light in air to the speed of light in the material. Conventional glasses have a refractive index of 1.52 and plastic has 1.50. High index plastic material have this index of refraction lying somewhere between 1.53 and 1.71.

As the index number increases, the lenses become denser and thinner leading to a light weight eyeglass. High index plastic lenses are lighter in weight. As the glass becomes more and more thin, it becomes more and more expensive. When very high index plastic is used, the material is very dense and hence increases the weight of the sunglass.

Astigmatism can also be corrected using high index plastic lenses. Bifocal and trifocal lenses are also made with the use of high index plastic material. These lenses are very thin and perfectly fit in wired frames which are very trendy. Even frameless frames can be used with high index plastic lenses. People who wear prescription eyeglasses can also now have the look of an elegant chic with this high index plastic material.

You have to be careful while buying your high index plastic eyeglass. Thin glasses are now available in optical centers for those with high prescription too. You must consult your optometrist before deciding the index of the lens you need.  When you choose the correct one then you will also have the most wanted style and trendy look and I am sure you can make heads turn.

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Chances are, if you saw clearly up until you reached your early forties you are noticing a condition called presbyopia. Do not worry; everybody experiences presbyopia at some point. Let us skip all the scientific reasoning presbyopia is doing this to you and just accept that it is natural, it happens, and this is reality. Easiest thing you can do is get glasses to correct for your new found fuzzy reading vision.

There are three general styles of eyeglasses you might be interested in using.

1) Single vision reading glasses are easy to use and are easily available. Readers have your reading correction covering the entire lens. This means that they are to be used only for near vision. If you look off in the distance through your reading glasses it will be blurry. If you see better in the distance through your reading glasses, go visit the eye doctor. Chances are you need a prescription pair of glasses or contact lenses.

2) Bifocal reading glasses are split lenses with no correction through the upper portion and your reading correction throughout the lower portion of the lens. Commonly referred to as Ben Franklin Glasses, these eyeglasses are perfect the reader who wants to leave glasses on for an extended period of time and still be able to see clearly in the distance.

3) Progressive reading glasses have the same benefit as bifocals, except rather than having a split style lens; they have a gradual channel of increasing reading add. To achieve an optimal graduated effect with your progressive readers, you may want to pick out a nice frame and bring them to a qualified optician to have the progressive lenses added in your correction.

For most presbyopic readers, either single vision or bifocal reading glasses makes the most sense. Remember that your new vision is natural, but that does not mean you can skip the visit to the eye doctor. Consider presbyopia a wake up call that you should have your eyes checked and get yourself a nice pair of readers that you will be proud to wear.

Suzanne Hughes writes quality information to help you navigate through the vision maze of life. She recently added a custom line of bifocal reading glasses to the existing line of reading glasses available at the online reading glasses boutique http://www.ReadinStyle.com

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Types of prescription eyewear lens

Single vision lenses

Your eyes might require vision improvement only for distance, only for reading purpose, or even for both. If you require correction only for distance vision, then you probably only want single vision lenses. With single vision lenses, you could look through all areas of the lens and it is visible clearly. If you desire vision improvement only for reading and in case you do not have astigmatism, then you could even purchase non-prescription reading glasses. If you do have astigmatism, you should go for prescription reading glasses. In either case, these are only considered single vision lenses.

Progressive lenses

Progressive lenses are sometimes as well recognizedas no-line bifocals, which are in fact trifocal lenses without the visible lines. Progressive lenses were urbanized as many people required the convenience of not having to change their prescription glasses for reading purpose, but they did not like other people to see the visible line. Progressive lenses do have an additional benefit however, which is that you sense a soft transition when you move your eyes from far away objects to close up objects. With a lined bifocal, the transition among viewing areas could even be somewhat uncomfortable.

Multifocal lenses

If you require vision adjustment for both distance and for reading purpose, then you could use two pairs of glasses, and swap depending on what you require to see. Or, you could even choose multifocal lenses (bifocal lenses, trifocal lenses, or progressive lenses). Many people find it not convenient to swap every now and then to another pair in order to read something.

Multifocal lenses divide the lens, so that part of the lens is kept for reading and another part of the lens is kept for distance vision. Bifocal (two areas) and trifocal (three areas) lenses have visible lines, which separate the diverse areas of the lens.

Prescription reading glasses

Non-prescription reading glasses just enlarge objects that are close to us, like the letters in a book. Your eye doctor could only decide the magnification power, which is most excellent for you, or you could figure it out by yourself through test and error. A doctor’s prescription is not sometime necessary in order to choose a reading lens. Drugstore reading glasses are just eyeglasses frames with enlarging lenses pre-loaded in a range of powers with stock lens powers. It is typically less costly to buy reading eyeglasses this way, but stock lens powers hardly ever offer an optimal vision correction. For best results, reading lenses with magnification customized to your requirements could be installed in any pair of eyeglasses frames.

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We are Specialised In Dispensing Progressive / Multifocal / Varifocal Lenses , Ultra Thin Hi-Index Lenses ( 1.9 Index Glass Lenses for Power as High As -24.00) , Anti Glare Lenses Like Crizal from Essilor etc, Photochromatic Lenses Like : Transition Lenses & Sunsensors ,Prescription Sunglasses

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