Tear flow measurement device

Patent metadata

Field	Value
Publication number	US-11730358-B2
Application number	US-202016786377-A
Country	US
Kind code	B2
Filing date	Feb 10, 2020
Priority date	Feb 15, 2019
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A lacrimal tear flow measurement device, and methods of manufacture and use, are described that includes a polymer microcapillary tube or similar structure having at least one end coated on the outside with soft silicone rubber and one end treated on the inside to be hydrophobic. The hydrophobic end keeps liquid from escaping or entering that end while allowing air to pass. The rest of the tube's insides may be hydrophilic or a neutral hydrophobe. As a Schirmer's test strip replacement, the entrance end of the device can be touched to the lacrimal lake of a patient's eye to collect suck up, or merely collect, tear fluid within the collection tube for weighing, volume measurement, or other analysis. Long-term collection devices for wear between doctors' visits can have a bypass channel allowing liquid to flow back onto the eye.

First claim

What is claimed is:

1. A tear secretion measurement apparatus comprising:
a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm), the capillary tube having a hydrophobic inner surface extending between 1 μm to 5000 μm from an exit end of the capillary tube and a hydrophilic or neutral hydrophile inner surface throughout a remainder of the capillary tube extending to an entrance end of the capillary tube.

2. The apparatus of claim 1 further comprising:
a silicone rubber covering over an outer diameter of the capillary tube at the entrance end.

3. The apparatus of claim 1 wherein the inner diameter of the polymer capillary tube is between 200 μm and 400 μm.

4. The apparatus of claim 1 wherein the polymer capillary tube is biocompatible.

5. The apparatus of claim 1 wherein the polymer capillary tube comprises parylene C, parylene HT, polyamide, polyether ether ketone (PEEK), polyethylene, or polypropylene.

6. The apparatus of claim 1 wherein a length of the capillary tube is between 2 millimeters to 50 millimeters (mm) and the remainder of the inner surface is hydrophilic.

7. The apparatus of claim 2 wherein the silicone rubber covering is a pre-formed silicone tube into which the polymer capillary tube was inserted.

8. The apparatus of claim 2 wherein the silicone rubber covering was produced by dip coating the polymer capillary tube in diluted, uncured silicone rubber and allowing it to cure.

9. The apparatus of claim 2 wherein the silicone rubber covering extends over an entire outer diameter of the capillary tube from the entrance end to the exit end.

10. The apparatus of claim 1 wherein the capillary tube is transparent or translucent, the apparatus further comprising:
volume measurement markings on an outer diameter of the capillary tube.

11. A tear secretion measurement apparatus comprising:
a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm), the capillary tube having a hydrophobic inner surface localized at an exit end of the capillary tube and a hydrophilic or neutral hydrophile inner surface throughout a remainder of the capillary tube extending to an entrance end of the capillary tube; and
a bypass channel extending from the entrance end and around an outside of the capillary tube to the exit end, the bypass channel configured to allow a predetermined ratio of liquid to bypass the polymer capillary tube.

12. A tear secretion measurement apparatus comprising:
a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm), the capillary tube having a hydrophobic inner surface localized at an exit end of the capillary tube and a hydrophilic or neutral hydrophile inner surface throughout a remainder of the capillary tube extending to an entrance end of the capillary tube,
wherein the polymer capillary tube is wound into a coil, the coil having an inner diameter between 11 millimeters and 24.5 millimeters (mm).

13. The apparatus of claim 12 wherein the wound capillary tube is fused to form a solid coil.

14. The apparatus of claim 12 further comprising:
a silicone rubber covering over an outer diameter of the capillary tube at the entrance end.

15. The apparatus of claim 14 wherein the silicone rubber covering is a pre-formed silicone tube into which the polymer capillary tube was inserted.

16. The apparatus of claim 14 wherein the silicone rubber covering was produced by dip coating the polymer capillary tube in diluted, uncured silicone rubber and allowing it to cure.

17. The apparatus of claim 14 wherein the silicone rubber covering extends over an entire outer diameter of the capillary tube from the entrance end to the exit end.

18. The apparatus of claim 11 further comprising:
a silicone rubber covering over an outer diameter of the capillary tube at the entrance end.

19. The apparatus of claim 18 wherein the silicone rubber covering is a pre-formed silicone tube into which the polymer capillary tube was inserted.

20. The apparatus of claim 18 wherein the silicone rubber covering was produced by dip coating the polymer capillary tube in diluted, uncured silicone rubber and allowing it to cure.

21. The apparatus of claim 18 wherein the silicone rubber covering extends over an entire outer diameter of the capillary tube from the entrance end to the exit end.

22. A tear secretion measurement apparatus comprising:
a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm), the capillary tube having a hydrophobic inner surface extending between 0.001% to 10% of a length of the capillary tube from an exit end of the capillary tube and a hydrophilic or neutral hydrophile inner surface throughout a remainder of the capillary tube extending to an entrance end of the capillary tube.

23. The apparatus of claim 22 further comprising:
a silicone rubber covering over an outer diameter of the capillary tube at the entrance end.

24. The apparatus of claim 23 wherein the silicone rubber covering is a pre-formed silicone tube into which the polymer capillary tube was inserted.

25. The apparatus of claim 23 wherein the silicone rubber covering was produced by dip coating the polymer capillary tube in diluted, uncured silicone rubber and allowing it to cure.

26. The apparatus of claim 23 wherein the silicone rubber covering extends over an entire outer diameter of the capillary tube from the entrance end to the exit end.

Assignees

• California Inst Of Techn
• Univ Southern California

Inventors

• Tai Yu-Chong
• Scianmarello Nicholas E
• Humayun Mark S

Classifications

• A61B3/101 Primary

  for examining the tear film · CPC title

• A61B5/6821

  Eye · CPC title

• A61B5/6867

  specially adapted to be attached or implanted in a specific body part (A61B5/6847 takes precedence) · CPC title

• A61B10/0045

  Devices for taking samples of body liquids · CPC title

• G01F22/00

  Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for · CPC title