PubMed · 9209978
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1997. Consultation section. Refractive surgical problem.. https://pubmed.ncbi.nlm.nih.gov/9209978/
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In 1889 August Müller (1864-1949) reported the correction of his own high myopia with a ground scleral contact lens that had been manufactured in Berlin two years earlier. This paper provides the first conclusive identification, based upon primary sources, of the manufacturer of these lenses. They were made by an optical engineer, Karl Otto Himmler (1841-1903), whose firm enjoyed, until the outbreak of World War II, an international reputation for the manufacture of microscopes and their accessories.
BACKGROUND: Models of oxygen delivery to the cornea with contact lens wear have considered the customary situation of one lens being worn on the cornea. However, two lenses, such as a rigid lens piggybacked on a soft lens, may be worn by patients with special ocular and visual needs. This paper extends existing single lens models to circumstances where two lenses offer resistance to oxygen in series. METHODS: Theoretical oxygen tensions are calculated for tear layers trapped beneath piggyback contact lens systems (and scleral lenses) and the anterior corneal surface with a simple single chamber corneal model using a personal computer software spreadsheet. RESULTS: Acceptable values are anticipated for contact lens materials of modern oxygen permeability values of approximately 60-100 Fatt Dk units under open eye conditions. CONCLUSIONS: The results of this spreadsheet model of oxygen supply to the anterior corneal surface offer a useful guide to clinicians concerned about providing their patients with physiologically acceptable piggyback lens systems.
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