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Choosing glasses. Pediatrics
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It is the spectacle lenses that compensate for the refractive errors that cause your poor vision. Therefore, choosing glasses, you must first choose the right eyeglass lenses. So, what you need to know when choosing eyeglass lenses:
Optical indicators (center distance, diopters) – this data should be given to you by a specialist in glasses selection after a complete examination of your vision. Of course, glasses should be ordered only in specialized departments of pharmacies or optics salons, where there is confidence that these indicators will be exactly met.
The refractive index (index) of a spectacle lens is the most important indicator of the class of a spectacle lens. The general rule is that the higher the index, the smaller the thickness and curvature of the lens giving the same diopters. And the stronger lenses you need, the more noticeable the difference. In practice, this means that high index lenses will be easier, they will distort your eyes and face less, and it will be easier for them to choose a thin and stylish frame. Modern lenses index varies – for optical glass in the range of 1.5 – 1.9, and for optical plastic – in the range of 1.5 – 1.7. Lenses with an index close to 1.5 are considered low index, and with an index greater than 1.6, are considered high index.
The material of a spectacle lens – currently the choice lies between glass and plastic. Definitely the advantage can not be given to either one or the other lenses. Plastic, as a material, is much softer than glass, and more vulnerable to damage. But all modern high-quality plastic lenses come with a hardening coating that makes them as scratch resistant as glass lenses.
The advantages of plastic lenses are lightness – the specific gravity of optical plastic is half the size of glass, and therefore your glasses with plastic lenses will be much lighter. Less traumatic than glass, as plastic is more resistant to splitting and its fragments are less dangerous – therefore, where to get 350mg soma pills are recommended for children, the elderly and drivers. Plastic provides great opportunities for processing, in particular for dyeing lenses.
The advantages of glass lenses – in general, the refractive index (index) of glass lenses is higher than plastic. In addition, the strength (except shock) of glass is higher than that of plastic. This means that high-quality glass lenses, with equal diopters, can be thinner and flatter than plastic.
Anti-reflective coating is a special technology that significantly improves the optical properties of a spectacle lens. Anti-reflex increases the transparency of lenses by 8-10%. Due to the greater transparency and lack of visual interference, lenses with an anti-reflex are more comfortable for the eyes and cause less fatigue during visual loads. At night, lenses with an anti-reflex allow you to see better while driving.
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Thus, the choice of glasses should start with the choice of eyeglass lenses, especially if correction of a high degree of myopia or hyperopia is required.
The frame of the glasses should adequately “straighten” your high-quality spectacle lenses. What you need to know when choosing a frame for glasses:
The frame can cause allergic reactions. When choosing a frame should pay attention to the predisposition to allergies. Cheap metal frames of unknown origin can cause severe where to get 350mg soma pills allergic reactions and irritations on the skin of the face.
The frame should be comfortable – when choosing a frame, special attention should be paid to such details as the mobility of the nose pads – hard nose pads often put pressure on the bridge of the nose and cause rapid fatigue. It is advisable to choose a frame with soft and movable (silicone) nano-pins. The size of the earbuds should strictly correspond to the distance from the rim to the bulge behind the ear. Temples should not exert pressure on the temples and the area behind the ear. When a large person, it is desirable to select a frame with a spring hinge. The frame should be comfortable and not cause fatigue even with prolonged use.
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The rim should you like. Properly chosen frame is important in creating the image and style of a person.
According to the materials of the site www.ophthalmolog.ru