Wearing a pair of glasses that are not suitable for you can affect your vision in serious cases, and even become a "killer" of the eyes, causing blindness. At present, there are three common misunderstandings in the purchase and wearing of glasses among the glasses family:

Misunderstanding one

Computer optometry as "optical prescription"

Choosing medical optometry is a prerequisite for accurate glasses.

Compared with the traditional medical optometry method, the computer optometry method is convenient and fast-put your head on the special instrument and stare at the image on the screen with both eyes, as long as you see it clearly, it is OK! But Kang Ying cautioned against using computer optometry as a "prescription for glasses." Especially for young people, computer optometry is prone to "overcorrection", which is likely to cause "false myopia" to evolve into "true myopia".

Analysis: The parameters of computer optometry are set based on the average value of human eyesight. Therefore, there will always be a gap between computer optometry and everyone's real eyesight. Accurate optometry must consider not only the refractive power of one eye, but also the balance of the eyes. Computer optometry is usually one eye, so the coordination of the two eyes must not be taken into account. More importantly, for people, especially teenagers, the diopter should not only be based on the static diopter. It should be dilated and reopted to obtain the true diopter.

The greater harm of computer optometry is that it causes "overcorrection" of optics. The correction of myopia should be the lowest for the best vision. However, many businesses provide consumers with the "most clear" power. In fact, this This kind of degree belongs to "overcorrection". Eyes who wear this kind of glasses for a long time will quickly lose their eyesight in order to adapt to this degree. A large number of surveys, especially those of people who have worn glasses for many years, show that wearing glasses after medical optometry is extremely unlikely to develop asthenopia.

Reminder: 1. The following people must undergo medical optometry: 1. Adolescents under 15 years of age. 2. Those who wear glasses for the first time. 3. Those who wear glasses and have visual fatigue. 4. Those with anisometropia in both eyes. 5. Those who have had eye diseases. 6. Those who need refractive surgery. 7. The short-term myopia has increased rapidly, such as the increase of 100 degrees within half a year.

2. Refraction cycle: Adolescents under the age of 18 are in the process of eye development. If they are nearsighted, they must undergo medical refraction once a year; if they are farsighted, they must undergo a medical refraction every six months.

Misunderstanding 2

The lens is thin and the material is expensive

Is the lens thinner the better? Is the material more expensive the better? the answer is negative.

Generally speaking, the thinner the lens, the better the light transmittance. But it does not mean that the higher the light transmittance, the better. Moreover, if it is myopia below 300 degrees, the lens itself is not thick, there is no need to spend a lot of money with a pair of ultra-thin lenses.

In terms of materials, expensive crystal lenses have always been admired in the past, but in fact, crystals are not suitable for making lenses.

The crystal has high hardness and is not easy to wear, but the natural crystal contains impurities, which are prone to streaks and bubbles. When light passes through, it will produce double refraction and produce double shadows. Moreover, its ultraviolet and infrared transmittance is high, and its protective effect on the eyes is not as good as ordinary optical lenses. In the past, people admired crystal lens because of its low absorption rate of ultraviolet and infrared, and the temperature of the lens was relatively low, and it had a cool feeling.

Analysis: Lenses are divided into three categories from materials: glass, resin, and space lenses, each with its own characteristics.

The glass sheet has superior optical properties, is not easy to scratch, and has a high refractive index. The higher the refractive index, the thinner the lens. Therefore, it is recommended to wear glasses for those with high myopia above 1000 degrees. However, the glass is fragile and the material is heavy, so fewer and fewer people choose glass.