Optical Microscopy

Optical microscopy is an observation technique capable of producing magnified images of objects or their details that are too small to be observed with the naked eye. The instrument used to perform this technique is called an optical microscope. To see an object clearly, a sharp image must be formed on the retina of the human eye. 

The lens has the properties of a converging lens that can change its shape and therefore its focal distance; its elasticity allows the eye to adjust for distinct vision at distances ranging from a minimum of about 250 mm, called the near point, to infinity, called the remote point. When one wants to examine a very small object in detail, one brings it as close as possible to the eye so that the viewing angle is as small as possible and the image on the retina is as large as possible. The smallest distance to which the eye can adapt for clear vision, however, is that of the near point. To overcome this limitation, one resorts to the use of a complex system of lenses called a microscope.