Earwigs eat aphids and several other harmful pests as well as hosta leaves. Some gardeners put up with the damage and leave the earwigs in the garden to control other pests. You can control earwigs with traps. Place a piece of crumpled paper under a flowerpot or use a tube of paper or bamboo as a trap.
In optics, refraction is a phenomenon that often occurs when waves travel from a medium with a given refractive index to a medium with another at an oblique angle. At the boundary between the media, the wave's phase velocity is altered, usually causing a change in direction.
Refraction is a test that optometrists and ophthalmologist use to measure a person's refractive error. a refractive error is when your eye does not bend light coming into your eye properly as it passes through the cornea, the crystalline lens and fluid media to come to a sharp, clear focus onto your retina.