What is round seg bifocal? | KOALAEYE OPTICAL

What is round seg bifocal?

What are bifocals?

A bifocal lens is a lens with two focal points. Because of the imaging principle of the lens, even half of the lens can still present a complete image, and the two images do not interfere with each other. In the past, both short-sighted glasses and presbyopia glasses were called single-focal lenses, which had only one focus. Later it developed to the bifocal lens, and the same lens is divided into upper and lower two parts. The upper part of that lens is used when seeing far, and you look down when seeing close objects, just the reading distance, naturally used the second half.


The fabric of eyeglasses cloth

Ordinary fabric: They are only applicable to the surface that has been cleaned.Because the ordinary fabric has no space to accommodate dirt, the surface of the cloth will be very dirty, and difficult to wash clean.

Microfiber fabrics: They are used wet to emulsify dirt and oil, and the microfiber is easier to wipe off. It is highly absorbent, making it very quick to clean the spilled liquid.

Fine fiber double velvet fabric: It feels soft, gentle, with the plump texture, but more single velvet.

Suede fabric: The feel and appearance are quite like natural suede, fine and smooth, soft and plump, used to wipe glasses. It will be clean and won't scratch the lens.



Why do glasses with the same prescription feel different?

The style of the frame has changed. The structure of the new glasses and the old glasses (half-frame, rimless, full-frame) may be different, and the angle of the glasses may also be different, which will cause visual differences and the symptoms of dizziness after wearing the new glasses. If you used to wear rimless glasses or half-rim glasses before and switch to full-frame glasses, you will feel that his field of view is limited and you will feel a little uncomfortable when you see the edge of the frame. If you wear full-frame glasses before, you will feel the edge of the lens when you change to half-rim glasses. It's too bright to adapt. There is another situation, changing from a frame with a nose pad to a frame without nose pads. Because the distance between the lens and the eye has changed, the position of the nose pad has also changed, which directly affects the relative position of the optical center and the pupil, as well as the distance from the back vertex of the lens to the cornea, which naturally affects the visual difference. In this case, you can fine-tune the nose pads, or after a short-term adaptation, you can generally return to normal.


What does vision insurance cover?

Vision insurance and vision benefit plans usually cover the cost of annual eye exams, prescription glasses, and/or contact lenses. Vision insurance includes traditional health/medical policies and health/discount plans that provide vision benefits and cover most. Coverage will vary depending on the type of vision insurance or vision benefit plan you choose. Group vision insurance is usually provided through an employer, an organization, or a government plan like Medicare or Medicaid. If you don't qualify for any of these options, you can purchase a personal vision care plan from a vision insurance provider.



Are the glasses purchased online of good quality?

Always, there are some people who question online shopping, whether the quality of the glasses purchased online is up to standard. Then I have to ask, is the quality of the glasses bought in the physical store good? Most people do not have the ability to judge the quality of glasses. It can be said that they decide which to buy based on an inexplicable idea. Therefore, for those who do not understand glasses, the quality of the glasses purchased online is not a question we should consider. In my personal experience, there has been no quality problem with the glasses purchased online, and for the same price, the glasses purchased in physical stores are much worse than those purchased online.


Design principle of aspheric lens

Early optical lenses use spherical lenses. Because the glasses were small round frames, the problem of lens edge aberration was not paid attention to. It wasn't until large frames became popular that the problem became apparent. For the spherical lenses, aberration cannot be corrected with the combined lens. Only a few variables of the lens can be found to reduce aberration and improve clarity. Aspheric lenses are designed to reduce the aberration of optical correction lenses and to make lenses flatter and reduce lens magnification. We can get clearer, thinner, lighter-quality lenses. Thus, aspheric lenses are used to reduce aberration and astigmatism to a minimum, close to the natural vision of the naked eye. The spherical aberration can be reduced by changing the curvature of the edge. The refraction in the central region is high and decreases evenly toward the edges.


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What Are Anti-Glare Glasses?

Anti-glare glasses are made with lenses that have an anti-glare coating or anti-reflective coating. This is an extremely thin layer placed on the lens itself so as to remove any reflections you might see from the surface of the glasses. This improves your vision by reducing the amount of glare that reflects off of your lenses.

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