At present, many people believe that the more expensive glasses are, the better! To grasp this psychology of consumers, optical shops often use refractive index as a selling point to increase the price of glasses in order to obtain higher economic benefits. The higher the refractive index, the thinner the lens, the higher the grade, and the higher the price! So is it true that the higher the refractive index of glasses, the better? Let's talk about it.
Good optical lenses should refer to lenses with good optical properties, which are reflected in high light transmittance, small dispersion, good wear resistance, strong ultraviolet protection, and good radiation protection.
Usually the refractive index of lenses includes 1.49, 1.56, 1.61, 1.67, 1.74, 1.8, 1.9. Myopia can be divided into mild myopia (within 3.00 degrees), moderate myopia (between 3.00 and 6.00 degrees), and high myopia (above 6.00 degrees). Generally speaking mild and moderate myopia (flat to 400 degrees) CHOICE refractive index is 1.56 OK, (300 degrees to 600 degrees) in 1.56 or 1.61 these two kinds of refractive index choose a bit more appropriate, 600 degrees above can consider 1.67 or 1.74 refractive index lens. Of course, these are not absolute, mainly according to the choice of the frame and the actual situation of their eyes to decide.
The higher the refractive index, the thinner the lens, the higher the technology required, the higher the price, but the lower the definition, the lower the refractive index will be!
The higher the refractive index is, the more refraction occurs after light passes through the lens, and the thinner the lens is. However, the higher the refractive index is, the more serious the dispersion phenomenon is, so the high refractive index lens has a low Abbe number. In other words, the refractive index is higher, the lens is thinner, but the vividness of the color is not as rich as the average 1.56. High refractive index lenses are usually used only for thousands of degrees.
The main advantage of high refractive index lenses is their thinness, which does not necessarily lead to good optical performance. Consumers in the choice of lenses, must choose according to different eye degrees to suit their own, excellent performance of the lens, blind pursuit of high refractive index is not desirable, suitable is the most important!
Post time: Aug-08-2022