What Are High-Index Lenses?
High index lenses are eyeglasses lenses that are designed to be thinner and lighter than regular lenses. High-index lenses have a high refractive index than their conventional counterparts. So, they are generally recommended for people who have significantly high refractive errors and strong prescriptions for nearsightedness, farsightedness or astigmatism.
High-index lenses correct all types of refractive errors. And they are also available as single vision lenses, or a reading prescription that corrects presbyopia, such as in a bifocal or progressive lens.
High-index lens has a higher refractive index and which is ranging from 1.53 to 1.74. A lens with an index of 1.74 could be up to 50 percent thinner than a regular plastic lens with an index of 1.50.
How to Choose Glasses for Long Face?
Bold shapes and eyeglasses with decorative details are also a smart choice since they help draw attention to your eyes and can add width to your face. Be sure to avoid narrow or rectangular shapes, which can make your face appear longer.
Square glasses: if you have a long face, you can try square glasses whose sharper corners can help to balance out the length of your face and complement your narrow features. Choose frames that are slightly wider than your cheekbones to make your face appear broader.
Two-toned glasses: if you have a long face shape, the two-toned glasses would be a good choice. The color-top frames create an optical illusion that draws focus upward toward your eyes rather than to the length of your face.
The characteristics of metal material
The material of metal glasses frame chooses some kind of metal material or alloy to make mostly. Most of the copper alloys are treated as the base material and then have surface treatment processing. Then there is the recent rise of pure titanium frames and those made of memory alloy. Metal frames are usually equipped with nose pads, which are movable to accommodate a variety of nasal shapes. The end of the temple is often covered with a plastic cover, not only beautiful but also to protect the temple and skin.
Disadvantages of progressive lenses
Wearing progressive multifocal glasses for the first time may cause slight dizziness and shaking when walking. Be careful when moving up the stairs. The perception of space changes, the perception of the distance of the object, and the perception of depth have changed. New wearers should not drive immediately and do vigorous exercise. When you look close, you need to turn your eyes down, and your eyes are mildly uncomfortable. Seeing the object through the blurred vision area around the lens, the object becomes blurred. Therefore, when new wearers look at things, turn their heads more, turn their eyes less, try to use the far-distance zone, the near-distance zone, and the middle-distance zone to see the object.
Material selection
General glasses material has plastic and metal two categories. Because the children's glasses degrees change faster, from the economic point of view, choosing plastic material is more affordable. And children love to move, they do not pay much attention to pick up and put on glasses. Choosing metal material is easy to distort, affecting the normal wearing. The material of the lens should be light and thin. The transmittance and refractive index should be high, and it should be wear-resistant and not easy to break.
Why Are My Progressive Lenses Blurry?
So, why are my progressive lenses blurry on sides? It can be caused by a lot of reasons, and we will list some of them.
The strength of progressive lenses is the factor that leads to initial peripheral blurriness. Progressive lenses tend to be blurry on the sides because each lens promotes three fields of vision. In addition, peripheral blurriness or haziness is a sensation that typically develops because more than one lens has been incorporated into one lens. The wearer also might feel as if he or she is moving from side to side.
After learning what may cause progressive lenses blurred, so how can you adapt to the progressive lenses? Therefore, in the following section, we will show you how to get used to progressive lenses.
How do anti-blue light glasses protect the eyes?
The anti-blue light glasses available on the market, no matter what type, etc., are mainly the difference in anti-blue light effect, light transmittance, and frame, which will affect the cost of glasses. Obviously, the lens is the most important of these. I think that it is basically enough to choose 30% to 40% anti-blue light glasses. It is good to cut off the harmful blue light. It is not necessary to completely eliminate the blue light so that the chromatic aberration will not be too large, the light transmittance is better, and it also has a certain anti-blue light effect.
Of course, to protect the eyes, it is not enough to rely on anti-blue glasses alone. The effect of anti-blue glasses is mainly to reduce the probability of eye diseases, and can not effectively relieve eye fatigue. Normal people between the ages of 20 and 40 blink about 20 times per minute. When you open your eyes and stare at a computer screen that changes rapidly, the number of blinks will be reduced to 4 or 5 times per minute, resulting in serious insufficient secretion of scum and dry eyes. Therefore, no matter how urgent the work is, you must pay attention to the rest of your eyes, close your eyes regularly, use eye drops when needed, and reduce the brightness of the screen as much as possible when looking at the screen. When the brightness of the screen is significantly higher than the ambient light It is easy to cause eye fatigue. Try to use it as little as possible in the dark. To be honest, it is more important to develop a good eye-using habit.
