What Is Bifocal Lens?
Changes in vision seem to be related to age. Presbyopia, a common eye condition that occurs in middle age, causes changes in your eye’s ability to focus. But this condition can be corrected by wearing bifocal glasses.
Bifocal lenses are divided into two parts to accommodate two different prescriptions in one lens. One area of the lens will have one prescription (usually distance) and a segment in the lower half will have the other (usually near vision).
The bifocal glasses were invented by Benjamin Franklin, who solved his own vision problem by taking the lens from his reading glasses and distance glasses and cutting them in half. Then remade the cut lenses into a single pair of bifocals and put the distance lens on top and the reading lens on the bottom.
A clear frame leads the way.
Clear glasses are almost always dominated by large frames. The big frame is an acceptable frame for any face shape. clear rimmed glasses are on the rise, so buy a pair before they hit the streets. Some are full of clean feeling, and the lens frame is slender and elegant. Some models are simple and versatile, suitable for all kinds of fashion styling. Light and fashionable, the collocation of clear frame and aureate glasses frame, is rich high-quality goods feeling.
To protect the lens.
Avoid getting chemicals on your glasses, and if you do, rinse with water immediately. If there is sweat and grease on the glasses, they should be washed to avoid corrosion. Do not use clothes or towels to wipe the lenses. Rubbing the lens with a rough cloth can cause scratches on the surface of the lens. So it is best to use special glasses cloth when you wipe the lenses, and when you wipe the glasses, you must hold the glasses on one side of the frame with your hand, and then gently wipe the glasses with the glasses cloth. Remember not to overexert, otherwise, it is easy to cause frame and lens damage.
Why do spectacle lenses fog up?
The fog on the surface of the lens is essentially related to the saturation pressure and water vapor liquefaction. The air is full of water molecules, which are constantly doing irregular movements. When there is no temperature difference, water molecules keep hitting the surface of the lens and will keep bouncing off. The lower the temperature, the slower the speed of movement. Therefore, when water molecules hit the cold lens from the hot air, on the one hand, they move too slowly to fly out in time. On the other hand, because of the relatively low temperature of the lens itself and its vicinity, the water vapor will liquefy. As a result, more and more water will accumulate on the lens and form small droplets, eventually forming a foggy layer. As the lens heats up, the mist evaporates back into the air, and the fog disappears.
What kind of glasses can people with round faces choose?
Always thought, like what has been said on the Internet, if you wear black frame glasses with large lenses, they can make you look small on the face. This is a mistake, because the black frames are too obvious, creating the wrong area on your face where the glasses are too small.
And for this kind of rimless glasses, because the bottom part is transparent, they will not destroy the partition, and you will feel the face is pretty sharp. For a man with a round face, the appropriate choice is a flat or pear-shaped frame. For a woman with a round face, in principle, she should avoid choosing any very obvious characteristics of the frame, and should not choose a too round or straight-line frame. Round faces are suitable for slender or square frames or pear-shaped frames. The human face of a round face is shorter, so, they had better match the slender glasses frame that takes curve slightly to reconcile the whole feeling. The square glasses or the frame with angle, are helpful for modifying the facial ministry line, highlighting the longitudinal line.
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.
Are blue light glasses good for driving at night?
Are blue light glasses helpful when driving at night? The answer is not necessarily. Anti-reflective coating on glasses is beneficial. But blue light blocking won't have any effect on your driving at night. If your glasses have an anti-reflective coating, then they might be helpful for night driving. Otherwise, they won't have any impact.
