How to choose a good lens?

Myopia is very damaging to the eyes, many people choose to match glasses to control the degree. But a good pair of glasses cannot be separated from good lenses, so, how to choose good lenses? Let's look at it in detail.

How to choose a good lens?

1, visible light transmittance, the higher the transmittance, the clearer the object;

2. Abbe number, the larger the Abbe number, the better. The smaller the Abbe number, the greater the dispersion, and the larger the dispersion, the easier to produce rainbow effect;

3, safety, the lens should be strong and durable, not easy to break, otherwise the lens broken easy to hurt the eyes;

4, anti-ultraviolet ability, the stronger the anti-ultraviolet ability, the more good for the eyes;

5, light, light, the ear and nose caused by the pressure is smaller;

6, refractive index, the same degree of lens, the greater the refractive index, the thinner the lens;

7, chemical stability, good chemical stability, to cope with the external acid, alkali, salt and air, water vapor corrosion resistance;

8, good wear resistance, poor wear resistance of the lens is easy to scratch, scratch, reduce the service life;

9, others, whether to add anti-reflection film, coating quality, solid resistance, etc., all affect the evaluation of the lens.

Select lenses must choose coated lenses, coated lenses can increase the light transmittance, up to more than 99%, can eliminate the lens before and after repeated reflection of the surface of the multiple rings, can eliminate the lens surface repeated reflection of the shadow, make the eyes more comfortable, coated lenses are generally added with ultraviolet absorbent, can absorb ultraviolet rays, to protect the eyes.

When a lens is selected, we should first understand which categories, what are the main performance characteristics of the lens, in the performance of the lens, the focus is the optical performance of the lens, such as light transmittance, refractive index of the lens, Abbe number of the lens, lens processing quality, lens surface treatment, etc. Know the above things, and then choose lenses according to the situation and requirements.