HARD CONTACT LENSES

1. A hard corneal contact lens having a rear surface in which all sections with planes which contain the optical axis are ellipses with an apex radius of curvature of 6.0 to 9.0 mm, characterised in that for use in a standardised lens system the ellipse has a numerical eccentricity in the range of 0...

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Bibliographic Details
Main Authors HOLLAND, RAINER, SCHWIND, HERBERT, MULLER, ULRICH
Format Patent
LanguageEnglish
German
Published 04.12.1985
Edition4
Subjects
CONTACT LENSES
OPTICS
PHYSICS
SPECTACLES
SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES
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Summary:1. A hard corneal contact lens having a rear surface in which all sections with planes which contain the optical axis are ellipses with an apex radius of curvature of 6.0 to 9.0 mm, characterised in that for use in a standardised lens system the ellipse has a numerical eccentricity in the range of 0.2 to < 0.4, that the elliptical rear surface, in a direction towards the edge of the lens, makes a transition into a peripheral bevel zone with a cross-section of circular segment form, which has a curvature opposite to the elliptical curve configuration and which at the transition has a common tangent with the elliptical curve configuration of the rear surface, and that when the lens is arranged horizontally the cross-sectional line of the bevel zone at the edge of the lens meets in right-angled relationship a vertical line through the edge of the lens.
Bibliography:Application Number: EP19810106194