What Pitfalls Must Be Avoided When Choosing Lenses?

Glasses matching is a kind of multi-link interaction, mutual restriction and system integration service. In this process, we need to pay attention to the accuracy of refraction, the selection of lens frame, the selection of lens, the processing and assembly of lens, and the adaptation and adjustment of lens frame. At the same time, after-sales service is also very important. Unqualified quality of any link will eventually lead to the disqualification of the brand. Many businesses that do not have the ability of systematic service, so they encourage customers to artificially separate the service of the system, and simply assume or paranoid that the influence of the system must be the influence of a single factor, which is very irresponsible. How can we avoid mistakes and pitfalls when buying glasses?

The higher the refractive index of lens, the better?

The refractive index of the lens is determined by the material of the lens. When the central thickness and the size of the lens are the same, the edge of the lens with high refractive index is thinner than that of the lens with low refractive index.

With the same brand and series, we can infer the price of lens by the refractive index. Basically, the higher the refractive index (except 1.56), the higher the price. Compared with different brands or different series of the same brand, the basic optical indexes such as effective light transmittance, wear resistance, antifouling (anti-static, oil-proof, waterproof, etc.) are quite different, so there is no significance in comparison. Only under the same quality conditions can the price be compared, so it is appropriate or expensive.

Simply comparing the absolute value of price and ignoring the huge gap in quality is a common "skill" used by marketing blunders.

There is a huge gap among different brands in the quality of single material, lens mold quality, coating and production process level, quality control ability and quality stability of lens manufacturing. It is more important to choose the own brand lens of professional optical lens manufacturers than to choose the refractive index. It should be noted that the lower the refractive index, the better (except 1.56).

The glasses fitting cycle is very long, and the average service life of a pair of glasses is 2-3 years. Therefore, in the actual matching process, it is necessary to consider the problems of visual quality, beauty and wearing comfort to achieve the best effect under the condition of wearing for a long time.

Aspheric lens is superior to spherical lenses?

Spherical lenses are a kind of lens with a convex or concave shape cut from a sphere. Because spherical lenses can't avoid aberrations and other phenomena, aspheric lenses (single aspheric lenses) have appeared to correct the shortcomings of spherical lenses.

An aspheric lens is a rotating surface (such as a parabola) with the same noncircular cross-section as all meridians. Its biggest advantage is that there is no distortion in the edge field of vision, and the edge of the lens is about one third thinner than that of an ordinary spherical lens.

At present, aspheric lenses are indeed closer to the naked eye's vision. The distortion of the lens edge is smaller and the field of vision is larger. It has become mainstream formulation. In addition, aspheric lens technology has been very mature, the price difference is very small. However, not everyone can adapt to aspheric lenses. It is not ruled out that some people's eyes can only adapt to spherical lenses. Therefore, there is no saying that the aspheric surface is higher than the spherical surface. It depends on personal adaptation.

What's special about double aspheric lenses?

Although double aspheric lenses have been introduced for many years. But at present, it is mainly Japanese manufacturers that can produce mature and stable double aspheric lenses, or brands with deep technical ties with Japanese manufacturers. Especially for the 1.60 aspherical lenses, the Abbe number of MR-8 material is 40, which is higher than the 32 Abelian number of MR-7 with 1.67 aspheric surfaces. The thickness and weight are close, the definition is higher and the field of vision is wider.

At present, the price of aspheric lenses is still relatively high, and its popularity is not high. In the future, double aspheric lenses will become the mainstream lens, and the price of spherical, single aspheric and double aspheric will be closer and closer.

Are anti-blue-light lenses, anti-radiation lenses and anti-ultraviolet lenses reliable?

First of all, the anti-radiation effect of the so-called anti-radiation lens is only the scope of the lens shielding. The electromagnetic wave is not completely linear propagation, and the harm of electromagnetic waves to the human body must be analyzed accurately. As for the harm of electromagnetic waves to the eyes, further empirical conclusion is needed. Moreover, all radiation glasses for computers and anti-reflective blue light glasses produced by regular lens manufacturers have radiation protection effects, so there is no need to add new costs for this.

Secondly, the optical lenses of regular lens manufacturers have anti-ultraviolet function (uv380 or above), because the anti-ultraviolet index is one of the many optical indicators, so there is no need to increase the cost for this. Moreover, the anti-ultraviolet function accounts for a very low proportion in the cost structure of the lens. Therefore, it is usually marketing enterprises that take the anti-ultraviolet function as the main "selling point". Some marketing brands improve the light transmittance by reducing the UV blocking rate, so as to promote the high definition of a certain series of products of their own brands. General anti-UV and anti-radiation glasses or anti-UV glass computer glasses have the function of anti-ultraviolet.

For people who have used computers or electronic display devices for a long time, the role of ant-blue-light goggles and anti-blue-ray spectacles can be confirmed at present. But they can only relieve the visual fatigue caused by blue light of electronic display screen, and the effect varies from person to person. In other words, it is very common for some people to have significant relief from visual fatigue, while others have no feelings.

Blue ray anti-glare glasses and anti-glare blue cut glasses are aimed at alleviating visual fatigue caused by electronic display screens. There is no further evidence to prove that they can effectively improve eye acid swelling, dry eye, vision loss and fundus lesions.

However, many businesses have regarded this as a marketing gimmick, and deliberately deify the anti-blue-light lens, through publicity, explicit or implied, to make people think that it can prevent or treat various ophthalmic diseases.

Are progressive multifocal and anti-fatigue lenses useful?

Progressive multifocal lenses were originally designed for a specific group of people. At first, it was designed for the presbyopia group who lost part of the adjustment ability, and then extended to the young people with insufficient adjustment ability. However, this group of people accounted for a small proportion. The gradual multifocal lens fitting requires higher requirements for refraction, lens frame selection and processing technology. It is necessary to determine the suitable frame face to face, to determine the pupil height (the accurate position of the lens optical center line point), and the after-sales service requirements are very high. Progressive multifocal lenses are not suitable for remote services. Many institutions often use progressive multifocal glasses to correct the vision of adolescents, claiming that they can control the increase in power, but there is no evidence to show that it has such a miraculous effect.

Using "anti-fatigue" to describe the lens itself has the suspicion of exaggerating the facts, because no lens can make the wearer use the eye without fatigue. The so-called anti fatigue lens, in fact, is a simple version of progressive multifocal lenses, which is just confusing in terms of name. Its requirements for optometry Technology (refraction and processing) are also very high, and not everyone can adapt to it. It is necessary to strictly, professionally and normatively refract before determining whether it is suitable.

The fundamental problem is not how to identify the authenticity of lenses, but the need to learn to think systematically. In view of the matching service which is integrated, only by finding first-class service with first-class reputation can we fundamentally guarantee the final quality.