Eyeglasses are used to help people with vision impairments to see clearly. There are many types of eyeglasses including single vision, trifocal, and bifocal eyeglasses. Single vision eyeglasses offer one type of vision correction. Bifocal lens has two separate areas. Each area is used to see things in different distance. The first area is used to see things in the near distance. The second area is used to see things in the far distance. The trifocal lens has three areas. The first area is used to see near things. The second area helps the person to see things in the intermediate zone. The third area is used to see things in the far distance.
Besides, you can add different types of coatings to the lens. The coating serves to protect the lens and make it more durable. Some of the coatings commonly applied to the lens include anti reflective, scratch resistant, photochromatic, and polarized coating. The anti reflective coating prevents the surface of the lens from reflecting the light so that you can see clearer. Sometimes, when the light shines on the eyeglasses, you will find yourself unable to see the object in front of you. The anti reflective coating eliminates this problem by preventing the light from reflecting on it. The scratch resistant coating protects the lens from scratches. It prevents the scratches from developing on the lens when you drop it on the ground. The photochromatic coating causes the lens to automatically darken when it is exposed to the sun. When you are inside a building, the photochromatic lens will transform from a darker tone to a lighter tone.
Scratch resistant lens is treated with a scratch resistant coating which reduces the chance of scratches developing on it. When a lens is scratched, the wearer will see scratches. With the scratch resistant coating, you don’t have to worry that the scratches will develop on it. Even if you use paper towel to wipe it, it will not show scratches. In case the eyeglasses drops on the floor, the lens won’t develop scratches because it is protected from the scratch resistant coating. Most of the eyeglasses lenses such as polycarbonate and plastic lenses are equipped with built in scratch resistant coating. It is up to you to add the scratch resistant coating. When buying eyeglasses, make sure you ask the optician about the warranty of the eyeglasses with scratch resistant coating versus the one without the scratch resistant coating.
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