Bifocal lens can be used to correct both far and near vision, mainly for presbyopia. The general distribution of bifocal lens is: the upper part of the lens is to see the distance, the lower part of the lens is used to watch the use of the near point, as for the size of the near norm, the nature of the near work to set.
Generally flat top dual lights are used most frequently, they only have a small area at the bottom of the lens for close-up work, while the periphery and top of the lens are used to look into the distance and provide a good peripheral view. Traditional double lens for a line of double light lens, the lens from the middle into two groups, which is less than half of the lens as nearly all point distance is used, they provide a good wide near point of view, for a long time in the near point workers has a better effect, architects, accountants, artists and other properties to work, This kind of lens can reduce the chance that the head moves. The urn-shaped double light is more suitable for children and young students to use, which can not only meet the wide vision of looking at the close, but also meet the need of frequent rearview transformation of the far vision of looking at the blackboard. Bifocal lenses can also be used, but only for people who need to read orthotics in close proximity, but it is not easy to take the glasses on and off when working in close proximity.
What Is Blue Light?
Sunlight contains red, orange, yellow, green and blue light rays and many shades of each of these colors, depending on the energy and wavelength of the individual rays (also called electromagnetic radiation). Combined, this spectrum of colored light rays creates what we call "white light" or sunlight.
Without getting into complicated physics, there is an inverse relationship between the wavelength of light rays and the amount of energy they contain. Light rays that have relatively long wavelengths contain less energy, and those with short wavelengths have more energy.
Rays on the red end of the visible light spectrum have longer wavelengths and, therefore, less energy. Rays on the blue end of the spectrum have shorter wavelengths and more energy.
The electromagnetic rays just beyond the red end of the visible light spectrum are called infrared - they are warming, but invisible. (The "warming lamps" you see keeping food warm at your local eatery emit infrared radiation. But these lamps also emit visible red light so people know they are on! The same is true for other types of heat lamps.)
On the other end of the visible light spectrum, blue light rays with the shortest wavelengths (and highest energy) are sometimes called blue-violet or violet light. This is why the invisible electromagnetic rays just beyond the visible light spectrum are called ultraviolet (UV) radiation.
is one of the most Potential Finished and Semi-Finished Optical Lenses factory located in Danyang City, China. It was establish in 2012 with covering 20000 spm and 150 employees. The annual production and sales of lenses are 30 million pieces, and the annual sales have exceeded 100 million for five consecutive years.
Our Key & Advantage Products:
Single Vision Lens:1.49;1.56;1.59;1.60;1.67;1.74
Bifocal Lens: 1.49; 1.56
Progressive Lens: CR-39; 1.56; 1.60
Functional Lens: Blue Cut, Photochromic; Photochromic +UV420 Blue cut; Sunglasses; Polarized; Polycarbonate
RX Service: Free Form; Special Coating; Special Power Range
|1. Could you provide samples?
|Of course, free samples can be sent to you, but please help us pay the freight fee.
|2. What Certification do you have for your optical lens?
|FDA, CE, ISO9001 certification is available.
|3. What is the MOQ of optical lens?
|We dont have Min Order quantity requirement. But if the quantity order is too small, we have to charge extra delivery fee.
|4. Could you provide OEM service?
|Sure, just send us your requirements.