What kind of glasses are bifocals?
Bifocals are mainly used in presbyopia correction, providing presbyopic opticians with a clear vision for both near and far use in one pair of glasses. The bifocal lens can be divided into two separate areas, with the upper part of the lens providing clear distance vision and the lower part providing clear near vision. The two regions of the bifocal lens provide different refractive forces, and the difference between these two refractive forces is the reading proximal addition, which compensates for adjustment during presbyopic reading.
What is blue light?
Blue light is an important part of natural light, and it is visible light with a wavelength of 400nm-500nm in the spectrum. Blue light can be divided into short-wave blue light (harmful blue light) and long-wave blue light (beneficial blue light). Short-wave blue light harms people’s vision and causes specific diseases, while long-wave blue light helps people maintain normal physiological functions, regulate biological rhythms, and treat specific diseases.
Blue light can be seen everywhere in daily life. In addition to blue light in the sun, electronic products such as TVs, computers, mobile phones, ipads, and LED lights also produce blue light in our daily.
How to Choose Glasses for Square Face?
Cat-eye glasses: cat-eye glasses are currently a very popular fashion trend. The upswept browlines provide curves and movement that are suited for any face shape. So, if you have a square face, you can try cat-eye glasses.
Oval glasses: oval glasses can soften your strong angles and balance your face and minimize your strong features. So, if you have a square face, you can try the oval glasses.
How to choose the best glasses for square faces? After reading this post, you may have some ideas. If you want to choose sunglasses for square faces, you can also follow the above suggestions. If you want to choose a new pair of glasses or sunglasses, Koalaeye glasses are recommended, which are stylish and at a cheap price.
The frame materials
You should choose the driver's glasses with alloy materials. The glasses made of this material are light and strong, so your ears won't be uncomfortable when you wear them for a long time.
What is a photochromic lens?
Photochromic lenses are lenses that become dark when exposed to a particular wavelength of light (usually ultraviolet light), but return to their original transmittance and become clear when no longer illuminated by the light source. Photochromic lenses can be made of glass or resin. The discoloration effect is caused by silver chloride or other halides added to the lens, which are transparent to visible light when not irradiated by ultraviolet light. When irradiated by ultraviolet light, chemical reactions will occur, which will absorb part of the visible light and make the lens show dark. The chemical reaction is reversible, so the lens returns to its original transparent state when it is no longer exposed to UV light.
Glasses may have different functional priorities.
Children's glasses focus on the treatment of eye disease, adult glasses focus on improving vision. To children with myopia, matching glasses is to improve vision really, eliminate fatigue, coordinate the muscles inside and outside of the eye, and can prevent myopia to deepen. For children, when they suffer from hyperopia, anisometropia, strabismus, amblyopia, and so on, sometimes they wear glasses to treat eye disease. It is the prerequisite for future vision improvement.
Who are suitable for progressive lenses?
A progressive piece is suitable for most old people to wear. The proper person is the one who has the visual needs of the long, medium and short distance cares about beauty, and is willing to accept new things. In order to avoid binocular vertical prism differences, for the wearer whose equivalent spherical lens with anisometropia is more than 2D, especially if the difference in refractive power of the vertical meridian is more than 2D, it should be checked with caution. Opticians whose vision needs do not match the progressive lens design, like dentists, often experience blurred vision when working with the far side of the lens to look closer.
