Although nobody ever knew when it was invented but probably it comes after the invention of the magnifying glass in 1266. During that time, Roger Bacon, an English monk was able to invent a glass that is capable of making the letters of the book appears larger and easier to read. The experiment was done by simply placing a piece of a ball of glass on the book. But of course, this was not the same thing as having a pair of eyeglasses to help him read. But eventually, someone had used this concept of glass experiment to able toinvent the eyeglass.
In fact, the first ever evidence of someone using an eyeglasses is a portrait of a cardinal painted in the year 1352 in Italy. In the portrait, the cardinal was seen wearing two framed lenses with their handles riveted together and are attached over the eyes. Eyeglasses had become more popular when printed books began to appear. This is when eyeglasses became a real necessity for many people especially those that are having problem with reading or those who had poor eyesight.
During the 16th century, there had been massive production of eyeglasses in northern Italy as well as in southern Germany. And in 1784, Benjamin Franklin was able to invent the bifocals. Bifocals are two different kinds of eyeglass lenses in a single pair ofeyeglasses.
A little understanding on how eyeglasses helps a person see better, we must know something about our eye’s construction. Our eye is like a ball, with a slight bulging at the front area. At the center of this bulge is the “pupil”. The pupil lets the light pass through inside the dark area of the eye. The light passes through the pupil to the "eye lens". The eye lens focuses the light which forms a picture at the back of the eyeball. At the back of the eyeball is a screen of light-sensitive cells called the “retina”.
The problem with a person’s difficulty to see object far or near lies on the position of its eyeballs. Some people have eyeballs that a little longer than the average (front to back); while other people are too short. This causes the lens of the eyes unable to focus vividly on the retina. Therefore, eyeglasses are needed to provide an extra set of lens. The extra lens of the eyeglasses corrects what a person lens does not. The resulting image is a sharp picture focused on the retina to which a person could see or read better.