Contact lens inspection method and system

Patent metadata

Field	Value
Publication number	US-10830666-B2
Application number	US-201715797257-A
Country	US
Kind code	B2
Filing date	Oct 30, 2017
Priority date	Oct 31, 2016
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

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.

First claim

The invention claimed is:

1. 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, wherein the at least one sectional image further comprises the lens center, wherein the method further comprises determining a sagittal depth of the contact lens ( 1 ), and wherein comparing the determined sagittal depth with a predetermined sagittal depth of a non-inverted contact lens to determine whether said contact lens ( 1 ) is inverted, wherein the at least one sectional image further comprises the lens center, wherein the method further comprises determining a sagittal depth of the contact lens ( 1 ), and wherein comparing the determined sagittal depth with a predetermined sagittal depth of a non-inverted contact lens to determine whether said contact lens ( 1 ) is inverted.

2. Method according to claim 1 , wherein the step of determining the cross-sectional edge geometry comprises determining a lens edge curvature radius of the convex surface ( 2 , 3 ) or of the concave surface ( 3 , 2 ) of the contact lens ( 1 ), and wherein the steps of selecting and comparing the parameter of the cross-sectional edge geometry comprise selecting the lens edge curvature radius of the convex surface ( 2 , 3 ) or of the concave surface ( 3 , 2 ) of the contact lens ( 1 ) as parameter defining the cross-sectional edge geometry and comparing said lens edge curvature radius with a predetermined lens edge curvature radius.

3. Method according to claim 2 , wherein the step of determining whether said contact lens ( 1 ) is inverted comprises evaluating whether the determined lens edge curvature radius of the contact lens deviates more than 10%, from the predetermined lens edge curvature radius.

4. Method according to claim 1 , wherein the at least one sectional image further comprises the lens center, wherein the method further comprises determining a lens diameter of the contact lens ( 1 ) and wherein the method further comprises comparing the determined lens diameter with a predetermined lens diameter of a non-inverted contact lens to determine whether said contact lens ( 1 ) is inverted.

5. Method according to claim 1 , wherein the contact lens ( 1 ) is imaged in a container ( 30 ), in an inspection cuvette or in a base part of a blister package.

6. Method according to claim 5 , wherein the contact lens ( 1 ) is imaged while placed in a volume of liquid in the container ( 30 ).

7. Method according to claim 5 , wherein the sectional image is used to further determine the orientation of the contact lens ( 1 ) in the container ( 30 ).

8. Method according to claim 5 , wherein the sectional image is used to further determine the Cartesian position of the contact lens ( 1 ) in the container ( 30 ).

9. Method according to claim 1 , wherein the contact lens ( 1 ) is a silicone hydrogel lens.

Assignees

• Novartis Ag
• Alcon Inc

Inventors

• Unterkofler Sarah
• Fechner Susanne
• Heift Marcus
• Schwab Matthias

Classifications

• G01M11/081

  by using a contact-less detection method, i.e. with a camera · CPC title

• G01M11/0271 Primary

  by using interferometric methods · CPC title

• G01M11/0221

  by determining the optical axis or position of lenses · CPC title

• G01M11/0207

  Details of measuring devices · CPC title

• G01N21/9515

  Objects of complex shape, e.g. examined with use of a surface follower device (measuring contours and curvatures G01B11/24) · CPC title