What is the progressive multifocal lens?
The lens of progressive multifocal glasses can change the refraction of the lens at the upper part of the central channel of the line of sight, which can effectively solve the difference of refraction when people view objects at different distances from long, medium, and short distances. Depending on demand, people have the flexibility to change or compensate vision according to visual distance, making it easier to help to adjust your vision in a variety of situations.
Advantages of progressive multifocal lenses
The progressive multi-focal lens has a number of different focal points from top to bottom. There's a smooth transition between seeing far and seeing close. There is no clear dividing line in the middle, like the myopia glasses, quite beautiful, and it is not dangerous. Because the added value is continuously and slowly increased in the gradient area, the wearer can get a continuous clear vision from the far point to the near point through the progressive lenses with the appropriate head position. In line with physiological optics, They help a better adaptation. Since the lens degree changes little by little, there is no phenomenon like jumping. Because the degree of the lens is gradual, so the vision from far to near changes slowly increase, which will not produce the adjustment of the eye fluctuation. It is not easy to cause visual fatigue. Without a degree line, the appearance will be more beautiful. Clear vision can be obtained at all distances within the visual scope. A pair of glasses satisfies both close and middle distances.
How to buy prescription glasses online?
To buy prescription glasses online, you should get a prescription and visit your local optician for an eye test. This test can be used not only to provide a prescription but also as a regular health check. Ask the optometrist for this data if you have had an eye exam and the optometrist provides a prescription. If you have an extra pair of glasses, send them to an online eyewear retailer to make sure the lenses have the correct 'visual center.' Measure the pupil distance. Ask your optometrist for this number, or get it from old glasses. Choose the right frame style to suit your face shape. Understand the frame measurements. Choose a suitable lens and its different lens film layer. Then place an order for glasses.
Points To Note When Choosing Frames
Choose a frame with lightweight, good elasticity, and stable structure. The lens frame with poor quality tends to deform in use, which affects the optical properties of the glasses. Pay attention to whether the two sides of the frame are symmetrical and whether it is fixed and safe enough. Pay attention to whether there are scratches on the surface of the frame. Just put on the glasses to feel if it is very tight or very loose, and they must be tight to reach the saturation condition. Pay attention to distinguish the advantages and disadvantages of the coating. The better coating frame has a uniform color, smooth surface, and clear identification. After using the frame with poor coating quality, the frame will soon rust and fall off, affecting the life of the frame, and even causing skin discomfort or allergy.
What is the best lens material?
Trivex is a special material from PPG. Compared with PC lenses, the refractive index is lower (only 1.53) but the Abbe number is higher (up to 45), which results in smaller dispersion and better image quality. At the same time, the impact resistance of the Trivex lens is 10 times higher than that of the PC. It is the only explosion-proof safety lens that can withstand external force twists and turns in the market at present.
The cost of an eye exam
If you have a Walmart Vision Center near you and you need a new or updated prescription, you can schedule your eye exam there. Some vision centers have independent optometrists who work in offices next to Walmart. An eye exam at Walmart costs about $73, depending on where you live. Call your nearest Walmart Vision Center to get the exact price of an eye exam.
Is there any relation between lens refractive index and lens definition?
First of all, in reality, from the point of view of the immediate situation, there seems to be no correlation. The refractive index is mainly related to the speed of light transmission into the lens. High refractive index lenses can be made thinner, lighter, and the technology required to do this is more sophisticated, so high refractive index lenses are more expensive. But does a high refractive index make the lens clearer? The higher the refractive index of the lens, the lower the Abbe number. The Abbe number is a very important parameter we use to measure the sharpness of the lens, which means that if the refractive index of the lens is high, that is to say, the sharpness of the lens is lower. If you have higher degrees, you can prioritize thinness and choose a lens with a higher refractive index, but don't overdo it.
