What Is Bifocal Lens?
Bifocal lenses are divided into two parts to accommodate two different prescriptions in one lens. One is for distance prescription and the other is for near vision prescription. Bifocal glasses are used to correct the presbyopia eye condition.
Bifocal lenses are with lines separating two different prescriptions. With bifocals, you don’t get the single-vision lens look with them as you do with progressive lenses. If you don’t need to see through two prescriptions, bifocal glasses are an excellent option. Bifocal glasses come with the following features:
- Two vision zone. (One for near vision and the other one for distance vision.)
- Has a distinct line separating the powers.
However, with bifocal glasses, you may have trouble reading computer screens and causing a greater risk for computer vision syndrome.
Choose the frame according to the face shape
Just like hairstyles and beards, frames should also be chosen according to your face shape. Of course, there is more than one frame for each face shape, and you can also prepare a few more pairs for yourself to match different styles. Try to avoid wearing spectacle frames that are too similar to the face shape, so as not to cause the lines of the face to be over-emphasized. Usually, the shape of the face is round, oval, square, rectangle, and heart-shaped. For example, if your face is square, you should choose glasses frames that are slightly wider than the shape of your face. This will make your face shape looks slightly slender. If the face is round, angular and square frames will help modify the lines of the face.
Acetate frame and plastic frame
What is the difference between acetate frame and a plastic frame? Acetate frames are lighter and generally considered to be better than plastic frames. Acetate is known for its hypoallergenicity, so it is a popular choice for people with sensitive skin. Unlike some plastic or metal frames, they can cause allergic reactions.
- The manufacturing process makes the plastic frame more brittle than the acetate frame.
- If the temple does not have a metal bracket, it is difficult to adjust the plastic glasses.
- There are fewer choices of colors and patterns for plastic frame
However, you will notice that acetate frames are generally more expensive than ordinary plastic frames. Spectacle frames are daily necessities that we use for a long time. Therefore, durability is essential, and the life span of the acetate frame is longer.
Does it take time to adjust to progressive lenses?
How long should it take to get used to progressive lenses? I have never worn glasses before.Progressive lenses were developed to allow easy switching between near and far views. Progressive glasses are divided into four parts. The upper part is the far-light region. The lower part is the near-light region, and the middle part is a variable light region. From top to bottom, if the hyperopia film is gradually increased and the myopia film is gradually decreased. The middle variable area is on both sides of the astigmatism area. Because of the prism effect, when you see things, through this area, the object will be blurred, and the eyes will feel uncomfortable. If the height of the frame itself is very small, the transition zone of progressive multi-focus is very narrow, and the eyes may not adapt to the sunglasses. The current design of progressive lenses is still not mature. Imported brands are relatively stable but expensive, and domestic brands are not mature in design. For various reasons, progressive glasses may be difficult to adapt to wearing.
How do drivers wear glasses or sunglasses better?
We should pay attention to the dim light at night on the impact of vision, At night, for the people who wear glasses, it is best not to drive, but to prevent fatigued driving. If you need to drive, you must choose clear and appropriate optical glasses. When the light is strong in the field, it is advocated to wear light-colored sunglasses with appropriate degrees to ensure driving safety. When wearing glasses to drive, for the observation of road conditions, we should focus on the use of the head movement. Do not use eyes to move, to prevent the effect of the prism, especially the patient with high myopia should pay special attention. Shaded sunglasses, coated with reflective material, block out light from above and increase horizontal and lower light, which makes it easier to see the platform. Clip-on sunglasses are suitable for people who wear glasses themselves. You can go straight with a pair of myopic sunglasses for a higher price.
How to Perform Glasses Measurements?
If there is no number on the temple of eyeglasses, you can perform glasses measurements by yourself. Now, we will show how to do that.
To measure the glasses’ size, you need to prepare a ruler or a tape first. To measure the frame width, measure the entire horizontal front of the frame, from the furthest extended point on either side. As for lens height, you should measure the vertical height of the lens. As for the bridge, you should measure the part that goes across the bridge of your nose. The temple arms include the front of the frame on either side and the rest behind your ear. The lens width is the horizontal diameter of one lens. So, when measuring these, you should be careful.
After that, you have measured the glasses frame size. If you want to know whether your face is right for this frame, you can read the post: How to Measure Face for Glasses Frames - 7 Steps
If you need a pair of new glasses, you can try Koalaeye glasses. They are stylish and cheap and they are lots of available choices.
Difference Between Driving Glasses And Night Vision Goggles
The special effect of polarized glasses is to eliminate and filter the scattered light in the beam of light effectively so that the light can be put into the visual image of glasses with the right track, and the field of vision is clear and natural. The effect of night vision goggles is that they allow the wearer to observe the surroundings at night without being affected by light. For example, aviation accidents can be greatly reduced through the use of navigation winches equipped with forward-looking infrared cameras on aircraft and by requiring pilots to wear goggles fitted with night vision goggles.