What Is a Gradient Lens?

There are many different types of lenses that help refract and reflect light. One type is the gradient lens. The gradient lens is most commonly thought of in relation to eyeglasses.

Definition

• Gradient lenses have a refraction that changes throughout the length of the lens. It usually goes from less powerful to more powerful, floowing along the length of the lens.

Examples

• Bifocal lenses are gradient lenses that have been used for centuries. Sunglasses often have gradient protective power. The most powerful protective section is found at the top of the lens. Protection fades toward the bottom of the lens.

Natural Occurrences

• Human eyes have a gradient lens; it helps focus light onto the back of the eye. The center of the lens is more powerful than the outer area, giving humans a strong, central focus.

Optical Illusions

• Gradient optics can create illusions by bending light, or making something appear where it is not. For example, sunlight reflecting off hot blacktop in the summer can create the illusion of a water puddle.