What are the quality problems of plastic lenses on the market_ And what kind of impact_ pre-stage,

What are the quality problems of plastic lenses on the market? And what kind of impact? pre-stage,

CCTV's "Weekly Quality Report" broadcast the quality investigation of plastic lenses: The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China conducted spot checks on 80 batches of resin lens products produced by 80 enterprises, and the results showed that the failure rate reached 19%, many of which lacked high-end production technology of resin lenses.

So what are the quality problems of plastic lenses on the market today? What kind of impact will it bring?1.740 high-definition green film myopia aspherical spectacle lens height number lens 1.Top power deviation is easy to cause eye fatigue top power deviation, that is, the power is usually called an important indicator to measure the quality of plastic lenses. A nominal 575-degree myopia lens, after testing, the actual power is 600 degrees, and its deviation is twice the tolerance (plus or minus 12 degrees) specified in the national standard.

In the test of other samples, it was found that the plastic lens produced by a company was judged to be a seriously unqualified product with a spherical top power deviation of more than 8 times the tolerance stipulated in the national standard. Inspectors said that glasses with a large deviation in top power will cause tension in the eye muscles and eye swelling and pain in the eyeball, causing eye fatigue.

Long-term wear can also cause nausea and vomiting. Especially for growing teenagers, the eye damage is huge.

(Recommended reading: How to judge the quality of plastic lenses2.The refractive index of false standard makes consumers spend money in vain The level of refractive index is not directly related to the performance of plastic lenses, which mainly determines the thickness of the lens and then affects the comfort, which is an important indicator that must be marked according to mandatory standards.

However, in the current plastic lens market, the refractive index and the price have a great relationship, the high refractive index lens is thinner and more comfortable to wear, the price is about 1000 to 2000 yuan, the medium refractive index resin lens is about 500 yuan and the low refractive index lens is only about 200 yuan. At present, the plastic lenses on the market are mainly low refractive index of 1.499, medium refractive index of 1.56 and 1.60, and the amount of high refractive index plastic lenses above 1.67 is relatively small.

The nominal refractive index on some of the plastic lens samples tested this time is about 1.56 to 1.60, but the test found that there are 7 groups of samples with unqualified refractive index items, and some of the nominal high refractive index plastic lenses actually have a refractive index of only about 1.50 or even lower, which makes consumers spend money invisibly.

(Recommended reading: Resin lens maintenance: 3.Dispersion coefficient is unqualified to mislead consumersSimilar to the "false standard" of the refractive index item of plastic lenses, there is also a phenomenon of "false standard" of dispersion coefficient.

The dispersion coefficient is an important parameter that reflects the imaging performance of plastic lenses, which directly determines the clarity of the lenses. In general, the higher the dispersion coefficient, the better the image clarity of the lens. However, the test found that there were 4 batches of resin lens dispersion coefficient items that were unqualified, and the dispersion coefficient marked was quite different from the actual value.

Among them, the dispersion coefficient of a sample lens is 38.5, but in fact, only 34.6 deviations have reached 10%, which far exceeds the standard requirement of plus or minus 4% tolerance. Inspectors say this will seriously mislead consumers about the clarity and choice of lenses. Zeiss 1.600A Series A60Plus Aspherical Lotus Film4.High-end production technology and products are still shortcomings, experts believe that although China's plastic lens production stall is large, but there is a lack of high-end production technology and products.

It is understood that at present, the raw materials of resin lenses and the equipment for hardening and coating are imported from abroad, and the processing technology used in high-end products also comes from abroad. The low end of the production technology of many domestic manufacturers has seriously reduced the quality and reliability of plastic lenses, and the fact that some enterprises have "high" refractive index that leads to unqualified products is actually the fact that the production technology is insufficient.

In addition, the lack of production management and factory inspection capabilities is an unavoidable factor that leads to the failure of plastic lenses. In the future, how to make more high-quality plastic lens products go to domestic and foreign markets? Experts believe that while gradually improving the level of scientific and technological innovation of China's production enterprises, we should strictly control the production, management and inspection of the manufacturers themselves, especially strengthen the training of professional talents, and inject more high-quality connotations into the title of the world's largest producer of plastic lenses.

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