<var id="hzhvh"><strike id="hzhvh"></strike></var>
<var id="hzhvh"><dl id="hzhvh"><progress id="hzhvh"></progress></dl></var><menuitem id="hzhvh"></menuitem>
<var id="hzhvh"><strike id="hzhvh"><listing id="hzhvh"></listing></strike></var> <menuitem id="hzhvh"><dl id="hzhvh"><progress id="hzhvh"></progress></dl></menuitem>
<var id="hzhvh"><strike id="hzhvh"></strike></var>
<menuitem id="hzhvh"><dl id="hzhvh"></dl></menuitem><var id="hzhvh"><video id="hzhvh"><listing id="hzhvh"></listing></video></var><menuitem id="hzhvh"><video id="hzhvh"><thead id="hzhvh"></thead></video></menuitem>
<menuitem id="hzhvh"></menuitem>
<cite id="hzhvh"></cite>
"

✅十大正规网络彩票app✅品牌实力,资金雄厚,十大正规网络彩票app,诚信为本,原生态App体验千百款游戏,十大正规网络彩票app,7x24服务,欢迎您来体验!

<var id="hzhvh"><strike id="hzhvh"></strike></var>
<var id="hzhvh"><dl id="hzhvh"><progress id="hzhvh"></progress></dl></var><menuitem id="hzhvh"></menuitem>
<var id="hzhvh"><strike id="hzhvh"><listing id="hzhvh"></listing></strike></var> <menuitem id="hzhvh"><dl id="hzhvh"><progress id="hzhvh"></progress></dl></menuitem>
<var id="hzhvh"><strike id="hzhvh"></strike></var>
<menuitem id="hzhvh"><dl id="hzhvh"></dl></menuitem><var id="hzhvh"><video id="hzhvh"><listing id="hzhvh"></listing></video></var><menuitem id="hzhvh"><video id="hzhvh"><thead id="hzhvh"></thead></video></menuitem>
<menuitem id="hzhvh"></menuitem>
<cite id="hzhvh"></cite>
"
Bausch & Lomb, Soft Contact Lens (1971)
2020年03月15日

Various individuals had experimented with glass contact lenses but wearers suffered frequent eye infections because the eye relies on oxygen from the air.

What was required was an oxygen permeable and transparent material. This is where Wichterle comes in as, along with a colleague Drahoslav Lim, he invented the first hydrogel material – hydroxyethyl methacrylate (HEMA).

HEMA was originally intended for use as an implant material. However, Wichterle realised its potential for eye wear and set to developing lens technologies that he patented in the US in 1962 and 1965.

Throughout the 50s and 60s contact lenses were produced individually. Wichterle devised the spin casting system that made producing larger numbers of lenses possible. His system involved pouring liquid HEMA onto a spinning mould, using centrifugal force to create the shape – and hence the magnifying quality – of the lens.

Heat was used to cure the lens in the mould and diamond cutters to finish to the required size.

American Robert Morrison and others helped Wichterle develop the lenses further before Bausch & Lomb stepped in to refine and commercialise the concept. After acquiring the patents, Bausch & Lomb launched the first soft contact lenses in 1971.

Hydrogels continue to be used for contact lenses today, but they are now cast moulded. New materials are also being sought – currently the industry is looking for a way of cost effectively producing daily disposable lenses in silicone.

十大正规网络彩票app