Prototypes of contact lenses exist since Leonardo da Vinci's 1508 Codex of the Eye, however the first time that such a devise was proposed to correct vision was in 1636 when Rene Descartes proposed a liquid-filled glass tube shaped to correct vision, however, this model was not practical for use since it prevented blinking. In 1801, Thomas Young constructed a devise that was not intended to correct vision but it was rather a learning devise for eye accommodation mechanisms, this devise is considered a precursor of contacts.
In 1845, Sir John Herschel proposed two ideas for vision correction, one of them being to form a mold of the cornea impressed onto a transparent medium, but it wasn't until 1887 when F.E. Muller, a glassblower from Germany, produced the first see-through and tolerated eye covering, and in 1888, Adolf Eugen Fick, a physiologist from the same country, began successfully fitting contact lenses in rabbits, himself, and later on in volunteers. These early contact lenses where 18-21mm in diameter, made of blown glass and the space between the eye and the glass had to be filled with a dextrose solution. Because of the size and weight of the lens, they could only be worn sparingly.
In 1929, Hungarian Dr. Dallos perfected a method to mold the cornea of a living eye and therefore allowed the production of lenses that conform to the shape of the human eye. In the 1930s, polymethyl methacrylate (PMMA/Plexiglass) was developed allowing the first glass-plastic lenses to be introduced to the public by optometrist William Feinbloom.
In 1949, corneal lenses were developed which sat exclusively on the cornea instead of over the entire visible ocular surface, these lenses could be worn all day long and in the 1960s they became widely popular. One problem with the PMMA contact lens is that its impermeable material does not allow the exchange of oxygen particles and therefore can have some adverse clinical effects, so at the end of the 1970s, and through the 80s and the 90s, many oxygen-permeable materials were explored and introduced into the manufacture of contact lenses.
In the 1960s the first "soft" lenses were introduced, following a breakthrough by chemists Otto Wichterle and Drahoslav Lim in Czechoslovakia, and in 1971 the Food and Drug Administration (FDA) approved the "Soflens" material in the United States. Since these soft lenses are more comfortable than the PMMA hard lenses, they became more and more prescribed and popular. With the creation and application of silicone hydrogels, which are highly permeable to oxygen, to contact lenses in 1999, the soft lenses comfort and safety was perfected and lenses were first approved for overnight use.
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