The lenses of prescription glasses
Common materials for lenses include glass, resin, and PC. The glass is fragile and heavy, and few people wear it anymore. PC film is tough and not fragile, but it is not resistant to high temperature and the surface is easily scratched. The most common type of lens on the market today is the resin lens, which is light in weight, hard to break, and reasonable in price. At present, it is generally recommended that you choose resin sheets, and it is recommended that people with ultra-high myopia choose glass sheets.
Generally, lenses can be divided into spherical and aspherical surfaces according to different curvature designs. When choosing, refer to the degree of the eye. For people with lower degrees, There are fewer differences between the two shapes. For people with moderate to high myopia, aspherical lenses will have better imaging effects and clearer vision.
When choosing a lens, a parameter that is often mentioned is the refractive index. Common refractive indexes are 1.56, 1.60, 1.67, and 1.74. With the same degree, the higher the refractive index, the thinner the lens.
Can you wear blue light glasses while driving?
The damage of blue light has a cumulative effect. The longer the exposure time is, the more serious the damage of retinal cells will be, which will eventually lead to irreversible damage of the structure and function of the retina. Once the retina has permanent damage, degeneration will directly affect the metabolism and function of photoreceptor cells, resulting in vision loss. It depends on the glasses you're wearing. The function of anti-blue light glasses depends on the material of the glasses. Some blue light glasses have a special anti-reflective coating, which can reduce glare. These glasses are definitely helpful when driving at night.
How long does it take to get used to progressive lenses?
Because the adjustment of each eye is different, so there will be some differences in the adaptation period. It usually takes about two weeks to get used to it. Probably many young people are familiar with this kind of lens, so they adapt to them for only a week or so and can restore the normal visual effect. If it's been two weeks and you still feel that you can't see clearly, or you have the feeling of nausea, etc., then you need to test and adjust. You need to go to the hospital to see the specific case, to find out whether it is a quality problem of the sunglasses, or there are some artificial reasons. If there is a problem, we should also replace the lenses in time, otherwise, it may lead to the problem of visual fatigue. Therefore, it is still necessary to promptly confirm the case of optometry, and then replace the appropriate glasses.
Different Types of Progressive Lenses
The first progressive lenses we want to introduce are computer progressive lenses, which are designed for clear vision in office settings. These lenses are ideal when using a computer for over 4 hours a day and help to reduce eye strain.
Computer progressive lenses are intended for indoor use and should not be worn over your regular glasses. The drawback to this is it requires you to have two separate pairs of eyeglasses.
How to buy contact lenses online?
Choose well-known brands.Nowadays, the contact lens brands in the market are mixed, with the proliferation of inferior products, but there are still some authoritative and well-known ones, like Johnson & Johnson, Bausch & Lomb, which are products recognized by most users, and you can rest assured to buy them.
The Disadvantages of Aspheric Lenses
Here, we will show some disadvantages of aspheric lenses.
The aspheric lens has a relatively small light area. When the eyeball rotates around, it will blur a little when looking at the outside through lens edge. In other words, the visual range of the line of sight becomes smaller.
Human’s eyeball is spherical and the eyeball rotates to the edge. Through aspheric lenses, the objects near the eye appear protruding.
Eyeglass frames are stylish equipment.
Since last year, the fashion industry has been experiencing a wave of glasses.Some fashion ICONS, mostly celebrities, are pretending to be short-sighted and wearing clear glasses. Recently, it is not difficult to find people wearing retro style when walking on the road, and retro style has become a popular style little by little. But what you might not notice is that clear glasses are showing off. In reality, clear glasses set off a wave of popularity in Euramerican already. Why did clear glasses become a trend?
Frame enthusiasts may own a dozen pairs of glasses with different colors and shapes. Different clothes go with different frames. It's the same with different hats and bags. The black frame is mature, so it can be used to attend some more sedate occasions. Encrusted diamond frame is in fashion, usually used when shopping, very fashionable. The round frame is the important prop that dresses up to be lovely.