Light Associated With Sunglasses

Direct Light - Direct light is light that reaches your eyes directly from a light source, such as the sun. Too much direct light obscures details of the surroundings and makes it difficult to focus.

Reflected light - Reflected light is usually in the form of glare. Reflected light is light that is reflected back to the eye from a reflecting object. Like direct light, strongly reflected light makes it difficult to perceive details or look directly at an object. Snow, water, glass and white sand are all good reflectors.

Diffused light - Diffused light is light that bounces off in many directions so that it does not appear to have a specific source. A typical example of diffuse light is the glow over a large city. It is difficult to identify a single source for it. Diffused light is the reason we can see even when there is no direct light source.

Good Sunglasses eliminate UV rays from the spectrum, reducing direct light for comfort, and also eliminate or reduce reflected light (depending on the reflective surface).

An interesting property of light is polarized light. When reflected off some surface, such as water, light becomes polarized. Due to the polarized nature of the reflected light, polarized sunglasses eliminate light that is reflected from water or similar reflective surfaces.