Method of manufacturing a tear flow measurement device

Patent metadata

Field	Value
Publication number	US-12239374-B2
Application number	US-202318344118-A
Country	US
Kind code	B2
Filing date	Jun 29, 2023
Priority date	Feb 15, 2019
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

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 method of manufacturing a tear secretion measurement apparatus, the method comprising:
providing a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm);
treating an inner surface of the capillary tube to be hydrophobic between an exit end of the capillary tube to 1 μm to 5000 μm from the exit end.

2. The method of claim 1 wherein an entire inner surface of the polymer capillary tube was a hydrophilic or neutral hydrophile surface before the hydrophobic treating.

3. The method of claim 1 further comprising:
modifying a remainder of the inner surface extending to an entrance end of the capillary tube to be hydrophilic by exposing to oxygen plasma or flushing with an oxidizing acid.

4. The method of claim 1 wherein the hydrophobic treating includes a treatment selected from the group consisting of coating with parylene HT, exposing to xenon difluoride or silanating gas, and treating with plasma.

5. The method of claim 1 further comprising:
forming a bypass channel extending from an entrance end of the capillary tube 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.

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

7. A method of manufacturing a tear secretion measurement apparatus, the method comprising:
providing a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm);
treating an inner surface of the capillary tube to be hydrophobic between an exit end of the capillary tube to 0.001% to 10% of a length of the capillary tube from the exit end.

8. The method of claim 7 wherein an entire inner surface of the polymer capillary tube was a hydrophilic or neutral hydrophile surface before the hydrophobic treating.

9. The method of claim 7 further comprising:
modifying a remainder of the inner surface extending to an entrance end of the capillary tube to be hydrophilic by exposing to oxygen plasma or flushing with an oxidizing acid.

10. The method of claim 7 wherein the hydrophobic treating includes a treatment selected from the group consisting of coating with parylene HT, exposing to xenon difluoride or silanating gas, and treating with plasma.

11. The method of claim 7 further comprising:
forming a bypass channel extending from an entrance end of the capillary tube 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 method of manufacturing a tear secretion measurement apparatus, the method comprising:
providing a polymer capillary tube having an inner diameter between 1 micron to 1000 microns (μm);
treating an inner surface at an exit end of the capillary tube to be hydrophobic,
winding the polymer capillary tube into a coil, the coil having an inner diameter between 11 millimeters and 24.5 millimeters (mm).

13. The method of claim 12 wherein an entire inner surface of the polymer capillary tube was a hydrophilic or neutral hydrophile surface before the hydrophobic treating.

14. The method of claim 12 further comprising:
modifying a remainder of the inner surface extending to an entrance end of the capillary tube to be hydrophilic by exposing to oxygen plasma or flushing with an oxidizing acid.

15. The method of claim 12 wherein the hydrophobic treating includes a treatment selected from the group consisting of coating with parylene HT, exposing to xenon difluoride or silanating gas, and treating with plasma.

16. The method of claim 12 further comprising:
forming a bypass channel extending from an entrance end of the capillary tube 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.

Assignees

• California Inst Of Techn
• Univ Southern California

Inventors

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

Classifications

• G01N33/4875 Primary

  Details of handling test elements, e.g. dispensing or storage, not specific to a particular test method (test-elements per se B01L, automatic analysers G01N35/00, in-vivo analysis on the human body for medical diagnosis A61B) · CPC title

• G01N2030/027

  Liquid chromatography · 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

• A61B5/6821

  Eye · CPC title