Speaking of glasses, everyone’s first feeling may be-not cheap.
Such a small pair of glasses costs as little as a few hundred dollars and as much as several thousand dollars. Isn’t it cheat people?
So some people went online to buy glasses worth tens of dollars, as if they looked similar.
But in fact, it is far from enough! Dozens of glasses and thousands of glasses, in addition to the price there are many differences, for their own eyes can’t be so careless.
Today, Dr. Clove will tell you how to choose a pair of glasses suitable for you.
There is a reason why you are expensive. Just choose what you can accept.
As we all know, big brand things are expensive to sell. For the same shape of the bag, big brands can sell tens of thousands, while small brands only sell hundreds. If the materials are similar, the difference lies in the added value of the brand.
The same is true for glasses. Better brands will adopt better designs to ensure beautiful appearance and safe structure of products, and have stricter standards for quality. Therefore, these glasses are not cheap by nature. After all, the cost has increased a lot.
In addition to brands, different materials, process requirements and mass production scale will also affect the cost, thus affecting the final selling price.
As for the choice of what-priced glasses, Dr. Clove’s advice is to choose the one with the higher price within your budget.
If one must say a range, Dr. Clove thinks that students can choose 500 ~ 1,000 yuan, and ordinary office workers can choose products with a monthly income of about 1/4 of the price.
Generally, a pair of glasses can be worn for about 2 years if they are well protected, so the average cost is not much per month.
Four Key Points of Choosing Glasses
To choose a suitable pair of glasses, we need to consider from four aspects.
The key prerequisite for suitable glasses is accurate optometry.
Foreign countries generally need professional optometrists to be qualified to issue optometry prescriptions, while domestic optometrists are not very standard. Many optometrists have only taken up their posts after a short period of training and do not have basic knowledge of ophthalmology. For some complicated situations, they may not be able to give appropriate optometry prescriptions.
Therefore, optometry should choose a qualified institution. If it is a teenager, a person with high myopia, a person with anisometropia, etc., mydriasis may be required, and it is better to go to the optometry center of the hospital for optometry.
Next, let’s talk about lenses.
Common materials of lenses include glass, resin and PC.
Glass sheet is fragile and heavy, and few people wear it. PC sheet is also called space sheet. It is tough and not easy to break, but it is not resistant to high temperature and the surface is easy to scratch. At present, the most common lens on the market is resin lens, which is light in weight, not easy to break and has a reasonable price.
At present, it is generally recommended that everyone choose resin sheets and those with ultra-high myopia choose glass sheets.
General lenses can be divided into spherical surface and aspheric surface according to different curvature designs, and the degree of the eye should be referred to when selecting.
For people with lower degrees, the difference between the two is not big. For people with moderate and high myopia, it is recommended to choose aspheric lenses for better imaging effect and clearer view.
3. Refractive index
When selecting lenses, one parameter that is often mentioned is refractive index.
Common refractive indices are 1.56, 1.60, 1.67 and 1.74. In short, at the same degree, the higher the refractive index, the thinner the lens. The selection suggestions are:
- Less than 200 degrees can be 1.50 or 1.56; 1.60 can be selected for 200 ~ 400 degrees; 1.67 can be selected for 400 ~ 800 degrees; For higher heights, 1.74 or glass lenses are recommended.
4. Dispersion coefficient
Another important parameter of resin lens is called [dispersion coefficient], which is used to measure the imaging clarity of the lens and is generally expressed by the reciprocal [Abbe number] of the dispersion system.
The number of Abbe is mostly between 30 and 58. The larger the number, the smaller the dispersion, and the better the imaging definition. Of course, the more expensive the price is, so you can choose on demand.
III. Mirror Frame
At present, the common materials of the frame are nonmetal and metal, the nonmetal mainly includes TR90, plate, etc., and the metal includes alloy, titanium, etc. Here is a brief introduction.
- TR90 and plate are actually plastic, But it is stronger and easier to process than ordinary plastics. Formability is good, so you can do a lot of fashionable styles, and do not deform at normal temperature. General alloy materials, firmness and flexibility are also good, the disadvantage is easy to fade. Pure titanium frame corrosion resistance and very firm, lighter than general alloy frame 40% or so, must be welded and electroplated in an oxygen-free state, requiring high requirements on equipment and technology.
Relatively speaking, the price of TR90 and alloy will be lower, and pure titanium will be more expensive. Everyone can make choices according to their own needs and budgets.
Select materials, then choose styles. Here are 3 suggestions.
The appropriate frame width should match the distance between the two pupils to ensure that the eyes can pass through the optical center when looking at things, so the large frame frame that many people like may not be the most suitable.
Choose the appropriate style according to the face shape. Generally, the principle of complementarity is followed, such as a square frame for a round face and a round frame for a square face.
After selecting the frame, you must try it on for a while to see if the weight is suitable and the style is like.