Myopia sunglasses to choose in what ways have you can consider?
In order to prevent eye injury by summer summer sun must choose a pair of appropriate sunglasses. Especially if myopia wear sunglasses quality is bad, not only protect the eyes, and the harm of eyes bigger, so must be careful when buying. Recommended reading: how to choose the best sunglasses now myopia want to wear sunglasses has the following several ways: contact lenses + sunglasses: this is not much said, the question is not applicable to the condition of the Lord. Polarized clip: clip is convenient, but not beautiful. And with a torque, easy to loose. Dye dyeing myopia sunglasses: general stores lens easy to become angry, life is not long. Professional lens factory dyed in advance, the color is stable, but the price is more expensive. Chip set of mirrors: absorption is more stable than clamp, but relatively heavy, and often wear, easy to wear. Myopia polarized sunglasses: function is very powerful. Sunshine, snow, road surface is formed on the surface of reflected glare, often cause eye discomfort and fatigue, polarized sunglasses these irregular reflect light, can be effectively filter, the surrounding scenery looks soft and not dazzling. Especially for driving, fishing, love sports, suggest it is better to match myopia polarized sunglasses. Even if they don't exercise regularly, buy also it's a good deal, light than the other way, fashion, and longer life. The disadvantage is that if myopic degree deep lens will be thick, can still within 800 degree. Of course can also with refractive index of 1. MR - 6 Eight lenses, will thin a lot, but the price a little expensive. Spread some glasses of common sense. Diopter: lens dioptre, the number of degrees is what we say at ordinary times, lens is one of the most important parameters. Thickness is basically is proportional to the diopter, but also can reduce the thickness of the lens. Refractive index, index of refraction is the speed of light in a vacuum and the ratio of the speed of light in the material. Under the condition of the same degree, the greater the refractive index lens the thinner, the lens is more light and more beautiful, the price also is higher, but the refractive index is not the bigger the better, it involves the abbe number of lens. Abbe number: different colors of light in the medium the refractive index is different, when after lens refraction, will be different, in the direction of propagation of light caused by the polychromatic light scattered sunlight in different color, this kind of phenomenon is the dispersion. The dispersion can affect vision clarity. Abbe number is used to measure the degree of dispersion, the greater the abbe number dispersion is smaller, conversely, the greater the dispersion. In general the refractive index, the greater the abbe number is smaller, the more serious the dispersion. So when choosing the lens can not blindly to pursue the large refractive index, driving up prices, reduced vision clarity. In general according to the degree of the lens to choose the refractive index, low degree of can choose refractive index is not big, can choose refractive index bigger degree high. High myopia can only choose high refractive index, otherwise the lens into the bottom of the bottle. Basically can choose refractive index according to the following method: choose 1 of 200 degrees. Option 1 50200 ~ 400 degrees. 50 or 1. Option 1 56400 ~ 600 degrees. Option 1 60600 ~ 800 degrees. More than 67800 degrees of option 1. 74