Lenses Is More Expensive Is Better?
In our concept, a price is a price, the more expensive means the better, but for the glasses we matched, expensive does not equal good, suitable is the most important.
For example, Li chose a pair of very expensive glasses, but the size did not look, just look at the expensive, then the odds of inappropriate will be high, it is possible to wear a few uncomfortable, put up "collection", so the glasses are not the more expensive the better, the right is the most important.
Lens selection:
Generally speaking, the higher the refractive index of the wrong piece, the better the transmittance, and the refractive index of the wrong piece determines the thickness of the lens. Under the same degree, the higher the refractive index, the higher the lens will be (the higher the refractive index, the more expensive the lens will be). But this does not mean that the higher the transmittance, the better, or to choose the refractive index suitable for their own degree. The general choices are as follows.
If you are nearsighted below 300 degrees, normal refractive index lenses will not be thick after processing, so there is no need to spend a lot of money with a pair of ultra-thin lenses. Generally, 1.50 or 1.56 can be selected within 300 degrees, 1.56- or 1.60 can be selected from 300-500 degrees, 1.67 can be selected from 500-800 degrees, and 170,1.74 can be selected from above 800 degrees.
In our philosophy, a price is a price, the more expensive means the better, but for the glasses we match, the expensive is not the same as the good, the right is the most important.
Lenses are divided into three categories: glass, resin and space lenses, each with its own characteristics.
Glass: superior optical properties, not easy to scratch, the higher the refractive index, the thinner the lens. But the glass is fragile and the material is heavy.
Space lenses: Also known as PC lenses, are more impact-resistant than resin lenses, thinner and lighter, and can protect against ultraviolet rays below 380 nanometers. Generally, it is recommended for people who like sports or outdoor activities.
The LENS HARDNESS OF CRYSTAL MATERIAL IS BIG, NOT EASY TO WEAR, BUT THERE are impurities in natural crystal, easy to appear stripe and bubble, when the light passes through, double refraction will be produced, resulting in overlapping. And the purple .
External and infrared transmission rate is high, the eye protection is not as good as ordinary optical lenses. Visible, crystal is not suitable for lens.
Therefore, glass lenses are gradually being eliminated because of their fragile and heavy wearing. Resin lenses occupy the market rapidly with their absolute advantages, so the thinner the lens is, the thinner the lens is
Good, is not the more expensive the material is better, according to the degree, and the required function of peach lens selection.
