Single Vision vs Progressive: What Are Their Differences
With single vision lenses, you can also just use the center of the lenses to avoid prismatic effects if your prescriptions are very unequal for both eyes.
As for progressive vs single vision, they also have differences in frame selection. You will stick to frames when choosing progressive lenses that will provide you with a minimum height of 14mm from the point you are looking through the lenses into the distance to the point you are looking down while you read.
Besides the above differences, they are also some other differences between single vision glasses and progressive lenses. You can choose either one based on your needs. To choose glasses, Koalaeye glasses are recommended. They come in stylish and at a cheap price.
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.
Magnesium aluminum spectacle frame
One of the characteristics of magnesium-aluminum spectacle frames is that they are resistant to corrosion, sweat and wear. In addition, spectacle frames made of magnesium-aluminum are also rich in color and look very textured, so many business people like to use such spectacle frames to display Its own charm.
The production process of titanium frames is complicated.
The production of titanium frames requires special processing equipment, special welding technology, and electroplating technology, which has many processing procedures and high production costs. In particular, some glasses choose the most difficult pure titanium andβtitanium. Titanium is very soft and very sticky, and very lively at high temperatures,so the processing is very difficult.
Have regular professional examinations.
The rimless glasses frame is directly punched on the lens and fasteners are added to fix the lens. It is easy to loosen the lens after long-term wearing. Therefore, it is recommended to regularly check and correct the glasses in the store when wearing rimless glasses. If the protective nut of rimless glasses falls off, stop using them immediately and repair them in time before wearing them. If screws and other accessories are loose, etc, be sure to go to the optical shop by the professional processing division to adjust.
What's wrong with your not clear phone's screen, low brightness, or even black screen when wearing polarized sunglasses?
There is a polarizing plate in the display structure of the mobile phones, which comes from the photoelectric modulation effect of the display screen. There is a polarized light absorption axis in the polarizing plate, which is consistent with the polarized light absorption principle of the polarized sunglasses. If the polarization absorption axes of the two are parallel, the screen can be seen. When they are perpendicular to each other, the light emitted by the screen will be absorbed by the sunglasses, and the light cannot reach the eyes, leading to the phenomenon of the black screen or low brightness. There may be differences in the direction of the absorption axis of the polarizer. So after wearing the polarized lenses, when you see low brightness or black screen, there are two different situations: landscape screen and portrait screen.
What is the bifocal lens?
Bifocal reading glasses are characterized by distance vision correction in the upper part of the lens and near vision correction at the bottom. If you need help with both, that's great. This lens is designed to facilitate the working of reading glasses and standard prescription glasses, all in one frame. Glasses are recommended when you are diagnosed with presbyopia, and bifocals are usually the first choice. But for intermediate vision, bifocals are difficult because they're not close enough for the reading part of the lens, and they're not far enough away for the distance part of the lens. Bifocal sunglasses have no magnification at the top, and the reading ability is at the bottom of the lens. Bifocal reading glasses can be found anywhere reading glasses are sold, but they can be harder to find than full magnifying lenses.
