"

yabo游戏手机版

  • "
    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.

    yabo游戏手机版 已完本玄幻小说排行榜 遮天 欢乐颂小说结局是什么 好看的小说完本推荐 灵域 玄幻小说完本 盗墓笔记同人小说 好看的历史书籍推荐 完美世界前传下载 旷世神医 盗墓笔记txt全集下载 大主宰之灵路天蚕土豆 盛世嫡妃 凤轻 小说 有声小说在线收听网 旷世神医 玄幻小说完本 盗墓笔记小说 小说 耳根 梦入神机 辰东完美世界有声小说 辰东 好看的课外书 我欲封天 耳根 小说零 好看的电视剧 斗破苍穹续集 古风君子以泽 千年殇 好看的玄幻小说 已完本玄幻小说排行榜 玄幻小说排行榜完本 完美世界辰东小说下载 穿越小说排行榜 穿越小说完本 盗墓笔记txt全集下载 言情小说 君子以泽 旷世神医 盗墓笔记有声小说 小说阅读网站 完美世界txt全集下载 小说阅读网站 古风 辰东 玄幻小说排行榜完本 欢乐颂第三季 大主宰 天蚕土豆 小说 盗墓笔记小说 我欲封天 耳根 小说零 小说阅读网站 完结小说排行榜 懒人听书 欢乐颂小说在线阅读 耳根 完美世界有声小说 大主宰 有声读物 魔天记 忘语 小说 官场小说排行榜 穿越小说排行榜 性爱有声小说在线收听