Classification of the lenses
The lenses can be mainly divided into glasses lens, resin lens, PC lens and so on according to the different materials. The lenses can be divided into daily use lens, protective lens and multi-focal lens according to the functions of usage.
How to clean the glasses
Clean with water by yourself The glasses lean on the nose, and the substances secreted by nose are greasy and acid, so you couldn’t wash them with clean water only.
Difference between single vision, bifocal and progressive
1. Bifocals help you get far and near vision only, and will generate image jumps when you look near after you see distance. 2. You will get continuous vision at distant, middle, and near focal ranges with progressive lens, and with no lines, no annoying image jumps. 3. progressive lens will be more expensive than bifocals. But the extra price is worthy of its value.
What is blue light
In 1958, J. Woodland Hastings and Beatrice M. Sweeney tested the ability of different wavelengths of light - corresponding to different colors -to shift the circadian rhythm in the photosynthetic marine dinoflagellate Gonyaulax polyedra. The greatest power to reset the organism’s daily meter lay in the blues, with a precipitous decline into the greens and a modest boost in the reds.
What are Bifocals
Bifocals are dual-version glasses, you can see two different fields of vision through one pair of bifocal glasses. Bifocals are designed with two prescirptions on the lenses, so you can see far through the top part of the lenses, and reading book or use computer through the bottom part of the lenses.