But that doesnât actually tell us what the difference is between the two. In reality, the difference between local and central fire alarms for renters insurance is based on who they alert. A local fire alarm sends a signal, usually a rather obvious noise that alerts residents of the apartment or building in question.
For other uses, see Cornea (disambiguation) . The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power.In humans, the refractive power of the cornea is approximately 43 dioptres. While the cornea contributes most of the eye's focusing power, its focus is fixed.The curvature of the lens, on the other hand, can be adjusted to tune the focus depending upon the object's distance.n humans, the refractive power of the cornea is approximately 43 dioptres. While the cornea contributes most of the eye's focusing power, its focus is fixed. The curvature of the lens, on the other hand, can be adjusted to tune the focus depending upon the object's distance.
The cornea also plays a key role in vision. As light enters the eye, it is refracted, or bent, by the outside shape of the cornea. The curvature of this outer layer helps determine how well your eye can focus on objects close-up and far away. There are three main layers of the cornea: 1  Epithelium. 2  The most superficial layer of the cornea, the epithelium stops outside matter from entering the eye. 3  This layer of the cornea also absorbs oxygen and nutrients from tears. 4  Stroma.