Contact
Lens History
For a relatively new science, it is surprising
that the 15th century thinker Leonardo da Vinci was the one
credited for contact lens history, at least in its most rudimentary
principle. Described along his journal, the 1508 Codex of the Eye
Manual D was a technique of directly altering corneal functions by
submerging an open eye in a bowl of water. This however, did not
directly approach the correction of impaired vision. The Codex was
simply observations based on the accommodation* of the eye and the
refracting effects of sight under liquid conditions. Yet, this was
an important knowledge where the foundation of the succeeding
generations of contact lenses will heavily revolve.
*process by which the eye manages optical
muscles to maintain a clear retina image, therefore focusing
power.
Later on, a 17th century rationalist René
Descartes made several solid attempts to further contact lens
history. Heavily influenced by the Codex, his invention was a
minute glass tube filled with liquid that is intended to be placed
in contact with the cornea. Though it wasn’t clear if his device
succeeded or failed in correcting vision, the device did not work
out as it was simply too fat for the eyelids to surround, making
even blinking impossible.
The mechanism of the eye’s accommodation was
further developed by the English thinker Thomas Young. Known best
for his contributions in physical optics, he was also the first to
consider the use of crystalline lenses. His lenses are liquid
filled eyecups which allow the vision to accommodate itself at
different distance relative to the changes of the lens’ curvature.
Thomas Young’s contribution to contact lenses was greatly
appreciated, though, like the original Codex wasn’t inclined to
meet the demands of correcting vision.
It was only until 1887 when the German
physiologist Adolf Eugen Fick had succeeded in creating what was
the first successful in contact lens history. Published in the
“Contactbrille”, by most part it already was the modern form of
contact lens. This sclera lenses, 18 – 21 millimeters in diameter,
are made from brown glass which would rest on the less sensitive
rim of tissue around the cornea. The empty spaces in between are
filled with grape sugar solution.
This however was still far from the best (if not
the most comfortable) in the contact lens history. Fick’s model was
heavy; the lens’ bearing on the sclera could only be tolerated for
less than an hour. Another German revised the model and came up
with his own, a lighter, contoured lens that allowed snugger fit to
the sclera thus enabling more time of usage before again it has to
be removed to allow the cornea to rest.
Then there was the PMMA. These Perspex-Plexiglas
lenses are combination of glass and plastic, allowing smaller and
lighter lens. PMMA lens became widespread; sophistication was now
added as part of the contact lens history as the barrier for
limited contact lens usage was now conquered.
Another recent breakthrough in contact lens
history is in 1999 with the silicone hydro-gels, which allowed soft
lens which to the delight of some, is perhaps the most comfortable
and durable form of lens.
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