Contact lens inspection method and system

US10830666B2 · kind B2 · utility

Assignee

• ALCON INC. · CH

Inventors

• Sarah Unterkofler · Großwallstadt, DE
• Susanne Fechner · Aschaffenburg, DE
• Marcus Heift · Aschaffenburg, DE
• Matthias Schwab · Amorbach, DE

Key dates

• Filing date: Oct 30, 2017
• Grant date: Nov 10, 2020
• Expiry date: Oct 24, 2038

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N21/9515
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for determining the inversion state of a soft contact lens (1), comprising imaging a soft contact lens having a convex surface (2, 3) and a concave surface (3, 2), a lens center and a lens edge (5) surrounding said soft contact lens (1), the method comprising using an optical coherence tomography system to obtain at least one sectional image of at least a part of the contact lens (1) comprising the lens edge (5), determining a cross-sectional edge geometry of the contact lens (1) extending from the lens edge (5) towards the lens center of the contact lens in the sectional image, the cross-sectional edge geometry corresponding to the convex and concave surface boundaries of the contact lens (1) in the sectional image, selecting a parameter defining the cross-sectional edge geometry of the contact lens (1) imaged and comparing the parameter defining the cross-sectional edge geometry of the contact lens (1) with a predetermined parameter defining a cross-sectional edge geometry of a non-inverted contact lens to determine whether said contact lens (1) is inverted.