Many people had a part in the invention of these helpful tools, called eyeglasses, to make our lives easier. To see where spectacles began, you need to study Roman times, when Seneca claimed to use a glass globe to maker reading easier. Similar viewing tools were said to have been used by the monks in the Middle Ages to help them read better as well. Later, in the 1400s, in Venice, glass blowers created glass stones that could have been held in your hand that had wooden frames. This is likely where today's magnifying glasses come from.
However, most people who have studied history have come up to the conclusion that the first pair of eyeglasses were made in Pisa, Italy, by kings in the mid-thirteenth century. They were small double magnifying glasses that were set into bone or metal. The person who wore them balanced them on the bridge of his nose so that he could see through them. This was depicted in a famous painting of the monks by Tommaso de Modena.
Early lenses were only used for nearsightedness, and it was not until much later, in the 1600s, that the concept of concave and convex lenses was learned so that both farsightedness and nearsightedness could be corrected. Later types, now known as bifocals, allowed people with both vision problems to be corrected as well. The first concept of these was believed to have been developed by Benjamin Franklin in the late 1700s.
Eyeglasses similar to what we see today, with frames, were first created in Spain in the seventeenth century. Ribbons of silk were added to loop over the ears of the wearer and were taken to China by travelers and Christian missionaries, where they added weights to hold them on better. The more rigid arms were created later by an optician named Edward Scarlett.
In the past, lenses were made of only blown glass, now popular materials include plastic and a stronger and lighter polycarbonate. Often times, if you have a stronger prescription, glass will be used automatically, due to the higher clarity that it provides. Plastic may be lighter, but it can scratch easier, so you may want to get a scratch resistant coating to help avoid problems.
Now, you can also get lenses that fit directly on the eyeball. These are called contacts. However, this requires a special examination and you can not have too high of a prescription.