What kind of lens is a progressive lens?
Progressive lenses are optical lenses designed for simultaneous correction of far, medium (for computer use), and near (for reading). They are Progressive Additional Lenses (PAL). The so-called progressive, The so-called progressive, is the use of polishing technology to achieve a gradual transition between the two focal lengths. The advantage of this design is that the wearer can see far and near objects alternately without taking off the glasses.
How many degrees of myopia do I need to wear glasses?
Students are the most nearsighted because they need to read and study every day. Many people have myopia during their student days. During the physical examination, everyone will check their eyesight first. Generally speaking, if the visual acuity is lower than 0.6, it means that you may be near-sighted to 0 degrees. At this time, you need to go for optometry to see the specific vision situation and see if you need to wear glasses. If the visual acuity tested exceeds 200 degrees, you must wear glasses at this time. If you do not wear glasses, your vision will be greatly affected, and the degree of myopia will rise quickly. For this reason, you must wear glasses in time to correct your vision. If the degree of myopia does not exceed 0 degrees, this is pseudo-myopia and does not require glasses. However, you should always take care to protect your eyes, avoid staring at things at close range for a long time, and don't let your eyes get too tired, so your vision will slowly return to normal.
How to test a blue-light lens?
Blue-light-blocking lenses are now focused on refractive indices of 1.56 and 1.60. If you buy lenses that are not of either refractive index, be wary. Of course, with the development of technology, now some brands have produced 1.71 refractive indexes blue-light-blocking lenses, suitable for people with high myopia to wear. The true lens package should at least have the product name, refractive index, dispersion coefficient, transmittance, color, SPH, CYL, and other indicators. These indicators are perfect, can be treated as the reference basis of the formal product. In addition, you can go to a professional optical shop or testing institutions for testing.
Method of taking off the contact lens
Wash your hands before removing contact lenses, and be careful not to leave long fingernails, to avoid contamination of the lenses by bacteria and nail scratches. Look up, open the upper and lower eyelids with the left index finger and right middle finger. Pinch the middle and lower edge of the lens gently with the thumb and index finger of the right hand, and remove the lens. You can use the index finger first to move the lens down, and then gently pinch the middle and lower edge of the lens with the thumb and index finger belly, and take off the lens.
What Are Bifocal Glasses?
Vision changes seem to be related to age. Presbyopia occurs in the middle age of one person, affecting your eye’s ability to focus. But it can be caused by bifocal glasses.
Bifocal glasses 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).
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.
However, the bifocal glasses come with some problems. So, in the following section, we will show you some common bifocal glasses problems.
How to Pop Lenses Out of Glasses with Plastic Frames?
In this section, we will show you how to take glasses out of plastic frames. It would be much easier to remove lenses from plastic frames because lenses are not fitted as tightly in them as in metal frames.
Now, here is the tutorial.
- Many plastic lenses will come out easily as you push through your thumb from the inner side and fix your fingers on the other side.
- If they do not come off, you can choose to heat the plastic a little bit so that it expands and allows the lenses to come out.
- To heat the plastic frames, you can immerse the glasses in a bowl of hot water. The water should be hot, not warm but of course only as much as you can handle amicably.
- Be careful to not drop your lenses in the bowl. Dry them with a no microfiber cloth and then you can remove them. You can’t use any towels because those can damage any blue light or anti reflective covering.
After all steps are finished, you can remove lenses from glasses.
Keyhole glasses are different from saddle glasses.
Glasses without nasal pads are common, usually with plastic eyewear frames and metal frames. Plastic frames without nose pads usually have a saddle-shaped nose area, therefore this type of bridge is called a saddle bridge. The keyhole is designed to touch the two points of the bridge of the nose, eliminating pressure from the top of the nose. This style is a bold fashion statement for both men and women. The design has short pads on either side of the nose, which is thought to be the most comfortable area.
