Regarding optics, I found that everyone has many misunderstandings.
Especially the 5 common pits below, I will correct them all at once today.
1. Wear glasses without optometry
Many people ignore the most important step before getting glasses: optometry.
Some people even use the optometry form printed by the refractor to match the glasses online, which is also undesirable.
The optometry sheet printed by the refractor is only a rough objective optometry data, and there is still a big gap between the fine-tuned prescription.
The fine-tuned prescription for glasses includes at least the degree of myopia/hyperopia, the size of astigmatism, the axial direction, the interpupillary distance of one eye, and the dominant eye. The parameters related to the specific frame are the pupil height and anterior inclination angle of a single eye.
Why go to a professional eye hospital or outpatient medical optometry?
? Practitioners are more professional and consider the situation more comprehensively;
? It can be distinguished whether it is true myopia or false myopia;
? Rule out eye diseases;
? Combine age, eye position, eye needs, visual function and myopia after mydriasis, etc., to give prescriptions for glasses;
? Pseudo-myopia, give eye protection guidance, medical treatment or visual function training if necessary
2. use the old power to match new glasses
In order to save trouble, many people will use the old power to match the new glasses, anyway, the power is not much different, and you can see clearly.
In fact, the degrees of the human eye will change. Even if the degrees of myopia and astigmatism remain the same, the direction of the astigmatism may change from an angle of 180 to an angle of 20. Also, you need to make appropriate changes when you wear a different frame, otherwise it is not conducive to Eye health, induce a variety of eye problems.
If you follow the new prescription/degree to customize the glasses, you can also effectively improve the quality of visual life, bring more convenience to work and study, and also help prevent amblyopia.
3.think that the thinner the lens, the better
The parameter to measure the thickness of the lens is the refractive index. The higher the refractive index, the thinner the lens.
Generally speaking, the refractive index is determined according to the degree of myopia. The higher the degree, the higher the refractive index of general lenses, such as 1.71, 1.74 and the like.
The higher the refractive index of the lens, the lower the Abbe number, and the relatively poor optical performance. The dispersion of the lens will be more serious, which will affect the reality of daily viewing; people with high power may have rainbow edges, which are clear and sharp. Will weaken slightly.
Moreover, a thin lens may cause a series of problems: the curvature is easy to change; the lens is fragile and so on.
So don't blindly pursue high refractive index (thin lens), but choose the refractive index that suits your own power.
4. think that the more expensive the lens, the better
Different prices have different craftsmanship, but the most important principle is not that the more expensive the better, but that it is stable, not easy to deform and suitable.
Therefore, after correct refraction, choose glasses that suit your face shape. Of course, it also involves interpupillary distance, frame size, frame material and other issues. Only glasses that meet medical standards, are of appropriate size, and are of comfortable material can be counted. Perfect! Otherwise, no matter how expensive the glasses are, they will not be qualified.
5. Be careful that the lenses you bought at bargaining prices were dropped
No matter what industry it is, there are always unscrupulous merchants who will drop customers' products, and the glasses industry is no exception.
Some optical shop businesses will stare at the customer and not see the difference between the lenses. When the customer is not satisfied with the price and makes the customer counter-offer to the price that the customer thinks is appropriate, they will make a much lower cost ordinary lens.
First of all, really good brand lenses will not have very low discounts. The price of the lens is relatively transparent, and the regular store will not sell it under a certain discount, and all the money is made for the fitting technology.
Of course, some optical shops will use ordinary lenses as brand lenses and sell them to customers deliberately at high prices. Even if the customers bargain, they will still make a profit. If some customers do not bargain, they will make more.
Therefore, everyone who wants to go to the store, start from entering the store, and advise you to save this step and that step. After the high price is reported, you will be asked to sell it at a 30% discount. You must be careful about this.
Note: Wearing glasses with obviously inappropriate prescription, unsuitable interpupillary distance, unsuitable pupil height, and unsuitable frame can easily lead to obvious visual fatigue, soreness and discomfort of the eyes, and even intermittent eye pain. If the visual fatigue lasts for a long time, it is likely to increase the degree of myopia.
