Usually, lenses and spectacles can offer wearers different vision experience of wearing in terms of peripheral sight. Such as, the vision area of spectacles is confined to its frames, whereas the lenses offer vision area as wide as possible. Therefore, one will find that objects are seemed blurry if not seen via lenses when with spectacles. Usually, people with different vision problems, like long or short sightedness, may have to put the lenses and eyes at different distance. On the contrary, lenses are meticulously made and can cover the whole cornea nicely. Therefore, contact lenses will lead to fewer troubles, like scratch.
It seems that contact lenses are much better than spectacles. Some people, however, are not good candidates for them. Therefore, many eye doctors will suggest a trial period, so as to know whether one can wear or not.
By and large, contact lenses can be categorized into two major groups, namely, soft lenses and RGP, both of them can be used to rectify many vision problems. The former can be adapted easily and quickly, and the later can be worn for longer time.
Some documents have it that the first designer of contact lenses is Leonardo Da Vinci, though he has failed to make a real one. And it becomes successful two hundred years later when Sir John Hershel has made some progress in the design. And the real modern-like lenses do not come into being until the year 1887. But they can not be used to rectify vision errors. And the ones that can be used for vision correction is designed by AE Fick, a German. After that, more and more achievements are scored in contacts and people can benefit greatly from these lenses.