preview

Small Round Lenses Research Paper

Decent Essays

There is a "trick" that makes high prescription lenses for nearsighted vision thinner. You can use it to minimize the lens thickness of even low index lens materials such as standard CR-39 plastic. The trick is buying small round lenses. The lens curvature of a minus prescription (for nearsightedness) is concave. That is, the lens is thin at the center and gradually thickens until you reach the edge where it's thickest. If you made the lens thin at the edge, it would be too thin at the center, which would make the lens too fragile. Therefore, these lenses have an absolute minimum thickness at the center to ensure its strength. This means that large lenses with a high minus prescription can have very thick edges. The lower the lens material …show more content…

High index lenses are compatible with a huge number of frame styles, which allows you to wear glasses you feel good about. A large selection is necessary to find a frame style that works best with the shape of your face. Not all styles are compatible with all types of faces. This is also true of frames made for small round lenses. Small round lenses may work for people with angular features because they soften their appearance. They also work for oval faces because any lens shape works for this type of face. However, these lenses can make people with round faces look cartoonish, and can look out-of-place on people with square faces. If you're physically active, your choice of sport frame styles is greatly diminished. They Provide Less UV, Glare, and Wind Protection If you spend lots of time outdoors, your eyes should be protected from ultraviolet. Avoiding UV associated eye problems require consistent use of glasses or sunglasses that block the sun's UV radiation. Lenses that block UV are less effective if they don't completely cover the eyes. UV light can enter the eyes by going around the lenses. In other words, the smaller the lens, the bigger the gap through which UV reaches the eyes. That's why sun glasses tend to be either large or tend to wrap around the

Get Access