The editor replied: Could it be the problem of the test pen?
There are three ways to identify whether a blue light-blocking lens has the function of blue light blocking:
(1) Test method of spectrophotometer. This is a laboratory method, the equipment is expensive, heavy, not easy to carry, but the data is accurate, sufficient, quantitative. It is not possible for general retail stores to adopt this method, but an alternative is to use the portable Blue Light meter produced by Shenyang Shangshan Medical Instrument Co., LTD., which can measure UV and blue light transmittance. This method is a multi-point wavelength-weighted average test, which can measure the combined blue light value, but there is no wavelength-divided test value.
(2) Test with the blue light-blocking pen on the market. This method has low cost, convenient test, and can be used for terminal display, but it has the following three problems: First, the blue light emitted by the blue light pen on the market is about 405nm, and the bandwidth is about 10nm. Blue violet light. Relatively speaking, this wavelength light source is easier to find. A blue light source with a central wavelength of 430nm requires a relatively special filter, and the price of a pen will go up. Second, the single point wavelength test is not sufficient for us. Third, we should also focus on the specific transmittance of each wavelength point, rather than a qualitative data. In summary, the use of blue light pen method is a last resort, you can choose to refer to.
(3) Use the enterprise’s self-statement. At this point, we should believe in the power of the brand and believe that most lens manufacturers will not cheat on the quality and efficacy of their products. For consumers, we can also use the same concept, for example, we say to customers: “This brand is a well-known international (domestic) brand, we have been selling for a long time, the user reputation is good, you can rest assured; This is the product testing report provided by the brand owner, issued by the national authority department, there will be no problem.”As for the second question, the answer is already obvious. The reason why the blue light pens provided by different manufacturers have different results in testing the same lens is that each blue light pen has a different spectrum range. Only the blue light pen with 435±20 nm can test the efficacy of the anti-blue light lens.
article source: https://www.hopesunoptical.com/news/how-to-check-whether-the-blue-light-blocking-lens-is-really-blue-light-blocking-why-do-you-get-different-results-when-you-test-the-same-lens-with-blue-light-blocking-pens-from-different-manufacturers/