Types and terms of magnifying glasses
Some people need magnifying glasses in certain circumstances, such as reading a newspaper, a book, the fine print on a map, a menu as well as examining a diamond or gemstone. Currently, there are various kinds of magnifiers, including Head Visor magnifiers and pendant necklace magnifying glasses. The first criterion is that the type of magnifying one chooses should match the use of it.
Magnifying glasses are now provided in different styles and designs. And different people need specific magnifying power. For instance, ordinary people may use a 5x hand held magnifier to examine windshield for defects. A pocket 10x folding magnifying glass is helpful for a border protection department as well as a police department. In addition, 20x jeweler loupes can be used by a county department of agriculture to examine crops for insect and blight problems.
For general reading, hand held magnifiers are convenient and helpful. For newspapers or books, people always use a magnifier with 3x or 6x magnification and 3 or 4 inch diameter. And for finer print materials, magnifiers with 8x or 20x magnification are needed. For people with low vision, magnifying glasses in standard design are not competent and they may resort to electronic vision aids which can offer greater magnification.
The following is the explanation of several terms of magnifying glasses. Magnifying power means the ability of a magnifying glass to increase the visual size of an object. A magnifying lens simply bends light in a special way and makes an image looks larger than an actual object. The X indicates the magnifying power. For instance, a 3x glass triples an image and 4x magnifiers magnify an object 4 times.
Focal length or working distance is another way to classify magnifying glasses. This element represents the distance that should be set between the magnifier and an object in order to get the optimal magnification effect. For example, a lens with 2x magnification and 5” focal length means that the lens can provide double magnification when it is held at a distance of 5” from the object.
Field of view simply indicates the size of the area that a person sees through the glasses. Depth of field is the distance that a magnifier can be moved above an object and still maintains focus ability. In general, depth field decreases as magnification power increases.
Reading eyeglasses for computer work
With the spread of computer use, more and more people are bothered by computer vision syndrome (CVS), symptoms of which include blurry vision, severe headaches and dry eye. In fact, CVS is a cumulative result of long-term of computer work. During the lasting computer tasks, some people are forced to strain their eyes.
Symptoms of CVS are actually common among regular computer users. And this group is still continually increasing so that protection against CVS is quite necessary. Currently, there are special computer eyeglasses particularly designed for performing computer tasks. Computer screen reading requires an intermediate vision zone, which is different from both distance vision and near vision. As a result, common prescription eyeglasses for myopia or hyperopia correction can not help in computer work.
Computer reading glasses are meant to decrease eye strain. These glasses are manufactured with a slight power that can bring down the focal length to a particular level. The power of computer glasses can be + 0.25, which is the lower limit. Properly maintaining focal length between the lens and the computer screen, most computer eyeglass lenses are produced with a powers ranging between + 0.25 and + 0.75.
In addition, computer reading eyeglasses are sold in ordinary eye stores without a prescription from the doctor. But customers are better to buy non-prescription computer eyeglasses from recognized stores. Of course, customers can get their computer eyeglasses customized in order to make them suit personal requirements and working environment.
Computer glasses also involve different styles with a wide selection of frames and designs. Most computer reading glasses are made of stainless steel that they feature lightweight. In addition to low weight ones, there are also rimless computer eyeglasses. Well-fitted computer eyeglasses can also block out harmful ultraviolet rays. In addition, computer reading glasses can also be applied with anti-glare coating, which can resist glare from the computer screen. Most computer eyeglasses are inexpensive.
Aspects of reading glasses
In the past, reading glasses were usually made of cheap plastic frames. There were only a few of styles for customers’ selection. However, these painted reading glasses had gained a great popularity among the public. Those glasses were quite similar so that a person might easily mingle with the crowd. The reason was that many people had a similar taste.
The situation has profoundly changed after several decades’ development of reading glasses. Nowadays, most people want to be distinctive from others. They are reluctant to follow the set trend. Reading glasses in special style or color enable a wearer to greatly change the appearance.
Currently, there are various designer reading glasses, which are widely used to do all the talking for wearers. These designer reading glasses can always meet personal needs of varying customers. Colorful frames and textures are all available now. Some people may choose chic glasses while some others prefer bold ones.
Moreover, simple slim reading glasses usually look very elegant and round frame glasses are classic. Both rimless and semi-rimless styles are there for selection. Some reading glasses are made of metal frames and spring hinges. It is commonly said that reading glasses would add a new dimension to one’s personality.
Reading glasses come in mainly two types: ready-made glasses and custom-made ones. Always in bulk styles, ready-made reading glasses are more likely to have some kinds of defects and the like. The most common defect is tiny bubbles inside the glass, resulting in visual distortion. One benefit is that these ready-made glasses are often quite cheap. A pair of this type typically costs $5 to $20. Due to this feature, many people keep more than one pair.
Reading glasses that are ready-made also come in lots of sizes. Some of them can be carried in small case. Foldable reading glasses have been created to minimize the space that is occupied. With a matching necklace, a pair of reading glasses in proper size and attractive style is surely to offer a satisfying look.
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Differences between Trifocals and Bifocals
Trifocals are a new group of special reading glasses which have three divisions on the lenses for correcting vision. It is different from traditional bifocals which have only two such divisions. The lower sections of the lens of trifocals are demarcated by a thin line which is a semi circular arc. One area is for near and the other for intermediate vision correction. And the part for intermediate rectification lies above the nearsighted correction area which is near the bottom of the lens. For those who used to wear bifocals may think it is strange to reading with glasses having three lines etched on it. As trifocals are new to most of people, it actually did need time for patient who uses this type of glasses to adjust to them. However, once you used to wear them, you will find it pretty easy to use and it is more convenient than bifocals.
After eye exam by the eye doctor, those people with extreme presbyopia, which means their net optical power with a special unit of diopter is very high, will be recommended to use trifocals. Because, unlike bifocals, trifocals can correct all ranges of vision, from nearby, intermediary to far distance, when bifocals can correct only two of them, either near vision or distance vision. Since trifocals can offer three levels of correction, it can give you a better vision. So, if you are one of the extreme presbyopia, you will get the better and more clarified vision when you use trifocals.
Trifocals are not only for those who have extreme presbyopia, it can also correct intermediate distance which can’t be provided by bifocals. For example, if your have a vision of -4 diopters, usually you will be recommended to use a glasses with a correction of 3 units, which means you vision is -1 diopter when you wear your reading glasses. The intermediate correction for such situation may be end up with a power of -2.5, which may take patients a little time to get used to it.
So with a single pair of trifocals, you can solve all problems that are related to presbyopia.
Description of black reading glassesDescription of black reading glasses
Reading glasses have evolved from those granny black reading glasses to the colorful ones today. However, black reading glasses nowadays have no longer been the old ones. They are also the fashions of our time and meet many personalities of their wearers.
When we talk about black reading glasses, we really mean the black framed reading glasses. If the lenses of reading glasses are black, you will never see close things with a clear vision, whether a map or just a book. The lenses of black reading glasses are usually non-tinted. However, the temples of Black reading glasses may be made with different colors, such as green, blue and yellow. Some people may think that the temple color should match the frame color. When it comes to reading glasses, this is not always the case. Sometimes, black framed reading glasses look more charming when equipped with green temples.
Black reading glasses do have certain variations. Rimless reading glasses usually have black temples. This kind of black reading glasses accent the simplicity of the lenses. The classic Trendies black reading glasses are just of this kind. In another case, black framed reading glasses may not be completely black. They can be a mix of other color but appear in dark effects. Betsey Johnson Rhinestone black reading glasses are the example.
Black reading glasses are available in different magnifying powers. When you search for them online, you can just select your proper power according to your reading prescription. The common power is +2.0.