Eyeglasses

[saroj.magar53]

The actual inventing of eye glasses evolved throughout a very extensive time period but the closest date to what could most nearly be classified as the invention of eyeglasses would be sometime in 1303 when physician Bernard of Gordon noted that the use of spectacles could be used in correcting long-sightedness and then later in the century it is speculated that Roger Bacon probably actually invented this device (Broton). From there on researchers began experimenting with curvatures and widths of lenses to eventually aid the visually impaired.Eyeglasses have a variety of structures to that are used for aiding and correcting defective sight. Generally they consist of a pair of lenses in a frame to hold them in the correct position in front of the eyes. Lenses are in most cases made of ground glass. A lens works by creating an image through the refraction of light. Each lens surface is made as a part of a spherical surface. To each surface there is what is called a center of curvature. This is the point in he middle of the sphere at which every point on the surface is equally spaced around.

[andrewglass]

yes ,i agree your opinion, glasses paly an important role in world. No glasses, i can't image what i could see these beautiful earth.

[zentaisuit]

Wearing contact lenses can also be ah, which is convenient but also beautiful, I like it, and now more and more people wearing contact lenses