Acquisition of optometric degrees when buying glasses online
The degrees are mainly got from three places: physical store paid optometry data, hospital optometry data, previous degree (remember or retest). If you are in the hospital for optometry, it should be noted that there must be test glasses to try on, if there are no test glasses to try on, the data is not accurate.
Why do nose pads turn green?
Because there are copper accessories in glasses. And the copper and sweat mix for a long time, so it will corrode and rust. The greenness is the mixture of copper salt (copper rust) produced by the copper element in the coating and inorganic salt in sweat and grease dust. The color of copper is green, so is the dirt. If you sweat a lot and the lens bracket is metal, the nasal bracket silica gel is easy to turn green. This is usually due to oxidation caused by the combination of nickel with the natural oils in the skin. Your nose is usually the oily part of your body. The oil in the nose mixes with sweat and then oxidizes the metal. Glass frames are usually made of a kind of copper called Monel. Monel is an easily corroded metal that does not react to many chemicals. It's skin-friendly. The only downside is that it turns green when it rusts.
What Are the Disadvantages of High-Index Lenses?
This section will show high index lenses disadvantages.
- High index lenses are made from a chemical synthetic blend that’s created through a special manufacturing process. So, high index lenses are expensive than regular lenses. In fact, the price may be more than double that of the traditional counterparts.
- High index lenses can be more brittle than their traditional counterparts and may also be more prone to scrapes and scratches. This can impact their overall durability.
- High index lenses are more reflective than regular lenses, which can make them less effective for brightly lit work environments, outdoor use and nighttime driving on busy highways.
- High index lenses have greater potential for distortion, particularly in your peripheral vision because the high index lenses have a higher Abbe value than prescriptions made from standard plastic or glass.
How to Know If You Need Bifocal Glasses?
As you get older, you will find that is more and more difficult to read or focus on things that are really close up. This is called presbyopia and it is a common eye condition among older people.
How to know if you need bifocal glasses? If you find yourself squinting at the text that once was easy to read or your vision is blurry, you may need to see an eye doctor. In this situation, you may need bifocal glasses to correct your eyes.
If you currently wear glasses but see print more clearly when you remove them, it is a sign that you may need bifocal glasses in the future.
To know if you need bifocal glasses exactly, check your eyes by an optometrist or ophthalmologist.
Is blue light blocking worth it?
There are two main problems with anti-blue glasses currently on the market. One is that the place to be prevented is not preventable, and the other is that people have color casts due to wrong protection and aggravate visual fatigue. Studies have shown that our eyes are the most intolerant of blue light in the 400-440 nanometer band. Therefore, current manufacturers mainly block blue light in this band when producing anti-blue glasses. However, the blue waveband of electronic products is between 450 nanometers and 490 nanometers, so most anti-blue glasses have little protection in this waveband. In addition, the blocking rate of anti-blue glasses is 20%~30% to achieve a good anti-blue light effect, but now the blocking rate of anti-blue glasses on the market has basically reached 80%~90%. All in all, these blocking blue light glasses cannot prevent the blue light in the 450-490 nanometer band, and their high blocking rate will also cause a color shift, which makes people more likely to have eye fatigue and headache.
In daily life, the intensity of blue light is low, not enough to cause damage to the fundus, so ordinary people do not need to wear anti-blue glasses unless they are working in extremely strong light conditions or working in special environments. To protect the eyes, it is more important for people to develop good eye habits. For example, wear a pair of suitable glasses and read insufficient light and at an appropriate distance. Avoid using electronic products for a long time. Take a break for 20 to 30 seconds every 20 to 30 minutes, and look at the distance regularly. If you have dry eyes while reading the electronic screen, remember to blink to 12 times per minute. It is best to wear sunglasses when outdoors.
Clean Glasses Properly
If the glasses are dirty, don't just wipe them with other cloth. If you use some hard cloth to wipe, it is easy to cause scratches in the lens. Generally speaking, the following cleaning methods are all feasible.
1. Use neutral or alkaline cleaning agent. Remember, toothpaste cannot be used as a substitute for the cleaning agent for spectacle lenses. General optical shops also sell lens cleaners in small bottles, which are easy to carry.
2. Go to the optical shop for professional ultrasonic cleaning. General optical shops provide free cleaning services. The ultrasonic cleaning machine can fully clean every gap and groove of the glasses.
3. Rinse the lens with tap water. Hold the frame in one hand and the cleaner in the other hand. Rub it slowly against the lens, and then rinse it off with clean water. Then wipe it with a glasses cloth or let it dry naturally.
In addition to the glasses cannot be cleaned with alcohol, you should also pay attention to their placement for daily maintenance. Try to avoid putting it under high temperature, and avoid oily, smoke, etc. If you don't use them, put them in the glasses case.
The Pros of Transitions Lenses
First, we will show you the advantages of the transition lenses.
Transition lenses or photochromic glasses are quite cost-effective. With the transition lenses, you don’t have to buy two pairs of glasses: prescription glasses or normal glasses and you do not need to switch them frequently. So, they are also convenient and bring you great convenience.
Carrying two pairs of glasses means that you are much more likely to lose or misplace either of them. Having only one pair of glasses can limit the risk of losing glasses. In addition, transition glasses provide more protection than normal sunglasses. They can filter out a good deal of harmful UV rays from the sun so as to protect your eyes.
What’s more, transition glasses come in a lot of different styles, shades, and tints suitable for anyone’s taste, so it won’t limit your fashion and make you look more fashionable.
