In terms of characteristics:
The hardness of glass lenses is very strong. For scrubbing, it can be heated to more than 300 degrees, while for resin lenses, it can only be heated to 80 degrees. The glass lens has a strong heat resistance performance. However, glass lenses are fragile and have a heavier weight, while resin lenses are different. They have good crush resistance and light weight. Compared with glass lenses, they are easier to process. However, because the resin lens does not have super heat resistance, the lens is relatively soft and easily scratched by foreign objects.
In terms of function:
The resin lens has the function of 100% anti-sunlight and ultraviolet rays, and prevents the eyes from all kinds of Harmful light damage, and glass lenses do not have the function of anti-ultraviolet rays, and the light transmittance of resin lens optical lenses is higher than that of glass lenses by more than 2%. But for highly myopic patients, the resin lens is thicker, so it will not look so beautiful to wear.
Although today's resin lenses have a great improvement effect, they are much thicker than glass lenses. Therefore, in terms of high temperature resistance, glass lenses are significantly better than life.
What is the difference between resin lenses and glass lenses? Resin lenses and glass lenses have their own advantages, but I personally feel that resin lenses are lighter than glass lenses. The pressure on the bridge of the nose is relatively small. And the impact resistance is relatively good, it will not be easily broken when subjected to external impact, and can protect the health and safety of the eyes and vision to the greatest extent. Therefore, resin lenses are more suitable for children and myopia patients with greater refractive power than glass lenses.
Common sense of lens material:
1. Material: AC﹕Acrylic (commonly known as plexiglass), cheaper and heavier , The clarity of the phase of the object is average, and the lens is easily broken under the influence of external force. PC: Commonly known as space lens advantages: light lenses (specific gravity 1.20 g/cm3), high strength and impact resistance, not easy to split, clarity better than AC but inferior to CR-39, generally used for sports glasses and protective glasses; as material When the thickness is up to 2.5cm, it can be used as bulletproof glass; PC sheet can almost completely absorb (or block) ultraviolet rays harmful to human eyes. This is especially suitable for drivers and computer operators. Disadvantages: 1. Easy to scratch and wear resistance up to B , All PC films must be coated with hard coating to improve the surface hardness of the focusing lens,
2, lens chromatic aberration is large
PL( CABTAC): Commonly known as Polylite film is a mainstream product in the future market, light and effective in passing harmful light and reflected light, viewing objects with high clarity and truth, the original film will not be broken but easy to scratch, generally used for outdoor fishing, and Students wear all fishing goggles and student mirrors when they are in class.
CR-39: commonly known as high-grade resin film, it is a high-definition lens, expensive, and lighter (specific gravity is 1.32 g/cm3)
Advantages: strong impact resistance, high temperature resistance, 10 times higher than glass, so the lens is not easy to break, and the break after broken is not sharp; the weight of the lens is light; the ultraviolet absorption function is better than ordinary optical glass p>
Disadvantages: The film is easy to scratch, and the assembled frame aspheric lens is required to be high. The resin film should preferably be coated with an anti-reflection coating to increase the transmittance of the lens
The reading glasses of the elderly should also be replaced regularly. Presbyopia is caused by the aging of the lens. As people age, the degree of lens aging will increase. Only the corresponding increase in the lens power required for correction can meet the needs of the daily life of the elderly.
There is no uniform rule for the specific replacement time. When the elderly feel difficult to read the newspaper wearing glasses, and the eyes are sore and uncomfortable, they should be replaced.
There are many lens materials on the market. The resin lens is light and easy to carry, but it is easy to scratch, so pay special attention to the maintenance of the lens. Glass lenses are cheap but fragile. Once broken, they may cause extremely serious damage to the eyeballs, so they are not suitable for teenagers who exercise more.