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EP-4384064-B1 - TECHNIQUES FOR QUANTITATIVELY ASSESSING TEAR-FILM DYNAMICS

EP4384064B1EP 4384064 B1EP4384064 B1EP 4384064B1EP-4384064-B1

Inventors

  • BAKER, KEVIN
  • CHOI, HYO WON
  • BORJA, DAVID
  • KUNNEN, Carolina

Dates

Publication Date
20260506
Application Date
20220630

Claims (9)

  1. An imaging apparatus (200) for tear film analysis of a contact lens worn on an eye, comprising: a corneal topographer (202) configured to project (301) a known pattern on a tear film surface of the contact lens (406) worn on the eye, wherein the known pattern comprises one or more placido rings (404) or a matrix of one or more dots; a digital camera (212) configured to capture (320) video data of the known pattern projected on the tear film surface of the contact lens (406) over a period of time, wherein the video data comprises a plurality of image frames (400, 500) and each image frame of the plurality of image frames includes a reflection pattern (402, 502) of the known pattern at a particular point in time at which that image frame is captured, the digital camera configured to capture the video data of the known pattern projected on the tear film surface of the contact lens (406) for at least one of different humidity levels, different eye drop types, or different blinking conditions, different contact lenses, and different contact lens wear times; and at least one processor (214), coupled with a memory, configured to cause the imaging apparatus to: perform image segmentation (330) on the reflection pattern (402) of each of the plurality of image frames (400, 500) to determine edges (410) of the known pattern (404), wherein the image segmentation is performed based on an artificial intelligence, Al, model trained for determining edges of one or more dots or placido rings (404) in the reflection patterns (402, 502) reflected off of tear film surfaces of contact lenses (406); generate a plurality (340) of displacement maps (602, 604) of the tear film surface of the contact lens based on the image segmentation (330) performed on the plurality of the reflection patterns (402,502), the plurality of displacement maps indicating changes (506, 508) to the tear film surface of the contact lens during the period of time, wherein the at least one processor (214) is further configured to cause the imaging apparatus to: determine one or more tear film breakup times based on a displacement of an edge associated with the one or more dots or placido rings (404) from at least a first image frame (400) to a second image frame (500) and indicated by the plurality of maps of the tear film surface; and output (350), based on the plurality of displacement maps, one or more metrics quantifying the changes to the tear film surface of the contact lens over the period of time, wherein the one or more metrics comprise one or more tear film breakup times associated with the tear film surface of the contact lens; and output one or more recommendations regarding the contact lens based on the one or more metrics that quantify the changes to the tear film surface of the contact lens over the period of time.
  2. The imaging apparatus of claim 1, wherein the one or more tear film breakup times comprise at least one of: a first tear film breakup time associated with a center portion of the contact lens (406), or a second tear film breakup time associated with a peripheral portion of the contact lens (406).
  3. The imaging apparatus of claim 1, wherein: the one or more metrics comprise one or more tear film breakup velocity metrics associated with the tear film surface of the contact lens.
  4. The imaging apparatus of claim 3, wherein the one or more tear film breakup velocity metrics comprise at least one of: a first tear film breakup velocity metric associated with a breakup of the tear film surface of the contact lens near a center portion of the contact lens (406), or a second tear film breakup velocity metric associated with a breakup of the tear film surface of the contact lens near a peripheral portion of the contact lens (406).
  5. The imaging apparatus of claim 3, wherein the at least one processor (214) is further configured to cause the imaging apparatus to determine the one or more tear film breakup velocity metrics based on a rate of change of displacement of an edge associated with the placido rings from at least a first image frame (400) to a second image frame (500) and indicated by the plurality of maps of the tear film surface.
  6. The imaging apparatus of claim 1, wherein: the one or more metrics comprise one or more tear film breakup magnitude metrics associated with the tear film surface of the contact lens (406).
  7. The imaging apparatus of claim 6, wherein the one or more tear film breakup magnitude metrics comprise at least one of: a first tear film breakup magnitude metric associated with a breakup of the tear film surface of the contact lens near a center portion of the contact lens (406), or a second tear film breakup magnitude metric associated with a breakup of the tear film surface of the contact lens near a peripheral portion of the contact lens (406).
  8. The imaging apparatus of claim 6, wherein the at least one processor (214) is further configured to cause the imaging apparatus to determine the one or more tear film breakup magnitude metrics based on an area of displacement of an edge associated with the placido rings from at least a first image frame (400) to a second image frame (500) and indicated by the plurality of maps of the tear film surface.
  9. The imaging apparatus of claim 1, wherein the one or more recommendations regarding the contact lens comprise at least one of: a recommendation to manufacture the contact lens with certain manufacturing materials, a recommendation to use certain eye drops with the contact lens, a recommendation to change a shape of the contact lens, or a recommendation to use the contact lens with eyes with a particular corneal shape.

Description

In the human eye, the precorneal tear film covering ocular surfaces is composed of three primary layers: the mucin layer, the aqueous layer, and the lipid layer. Each layer plays a role in the protection and lubrication of the eye and thus affects dryness of the eye or lack thereof. Dryness of the eye is a recognized ocular disease, which is generally referred to as "dry eye," "dry eye syndrome" (DES), or "keratoconjunctivitis sicca" (KCS). Dry eye can cause symptoms, such as itchiness, burning, and irritation, which can result in discomfort. There is a correlation between the ocular tear film layer thicknesses and dry eye disease. For wearers of contact lenses, a widely reported ailment to physicians is intolerance to prolonged contact lens usage. Contact lens wear can contribute to dry eye. A contact lens can disrupt the natural tear film and can reduce corneal sensitivity over time, which can cause a reduction in tear production. In some patients, contact lens wear becomes unmanageable due to pain, irritation, or general decrease of visual acuity due to ocular discomfort. Typical remedies include repetitive eye drop applications, alterations of daily activity, or repeated removal of the contact lenses and return to standard eyeglasses or poor vision. For physicians, a typical treatment regime of revised medications and replacement contact lenses is tried and evaluated until a recommendation to alternative vision correction is employed for the patient. For many of these patients, evaporative dry eye disease is an underlying cause for their contact lens intolerance. Reference is made to Mousavi M, et al: "The utility of measuring tear film break-up time for prescribing contact lenses", Contact Lens and Anterior Eye, Stockton Press, Basingstoke, GB, vol. 41, no. 1, 2017-08-30, pages 105- 109, XP085333576, ISSN: 1367-0484, and to Nur Amni Batrisyia Shamsul Amri et al: "An Overview of Dry Eye Analysis Algorithms for Tear Film Break-Up Time Detection", 2021 IEEE Symposium on Industrial Electronics and Applications (ISIEA), IEEE, 2021-07-10, pages 1-6, XP033959118 which have been cited as exemplary of the state of the background state of the art. Mousavi et al. discusses evaluating the clinical value of non-invasive keratograph tear film breakup time (NIKBUT) for prescribing contact lenses. A commercial instrument automatically detects the time to the first discontinuity in reflected Placido rings. This NIKBUT value is then compared to a clinician's prescription choice. Nur Amni Batrisyia Shamsul Amri et al. provides an overview of algorithms for Tear Film Break-Up Time (TFBUT) detection from fluorescein videos. It describes methods including using a Convolutional Neural Network (CNN) to classify image regions into categories such as 'Break-up Area' to detect breakup. SUMMARY The scope of the invention is in accordance with the appended claims. In certain arrangements of the specification, a method, not claimed in the appended claims, for tear film analysis of a contact lens worn on an eye is provided. The method includes projecting an image of one or more shapes on a tear film surface of the contact lens worn on the eye. The method further includes capturing video data of the one or more shapes projected on the tear film surface of the contact lens over a period of time, wherein the video data comprises a plurality of image frames and each image frame of the plurality of image frames includes a reflection pattern of the one or more shapes at a particular point in time at which that image frame is captured. The method further includes performing image segmentation on the reflection pattern of each of the plurality of image frames. The method further includes generating a plurality of maps of the tear film surface of the contact lens based on the image segmentation performed on the plurality of the reflection patterns, the plurality of maps indicating changes to the tear film surface of the contact lens during the period of time. The method further includes outputting, based on the plurality of maps, one or more metrics quantifying the changes to the tear film surface of the contact lens over the period of time. The invention is defined by the features of independent claim 1. Preferred embodiments are defined in the dependent claims 2-9. Aspects, embodiments and examples disclosed herein which do not fall within the scope of the appended claims do not form part of the invention and are merely provided for illustrative purposes. The imaging apparatus includes a corneal topographer configured to project a known pattern on a tear film surface of the contact lens worn on the eye. The imaging apparatus also includes a digital camera configured to capture video data of the known pattern projected on the tear film surface of the contact lens over a period of time, wherein the video data comprises a plurality of image frames and each image frame of the plurality of image frames includes a reflection pattern of the known