Dry Eye Symptom Mitigation by Oral Intake of Probiotics

September 24, 2025 updated by: Chung Shan Medical University

A Clinical Trial of Dry Eye Symptom Mitigation by Oral Intake of Probiotics

This study investigates whether the oral intake of a probiotics capsule product may relieve dry eye symptoms. Participants will be aged between 20 - 65 years of age, with confirmed diagnosis of dry eye status. The participants will be assessed for several parameters and asked to take 1 probiotics capsule per day for 35 days. The parameters will include ocular surface health, tear volume, tear quality, intraocular pressure, tear osmolarity and serum biochemical test. After the 35 days are completed, the participants will be assessed again for the same parameters.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This investigation is a randomized, double-blind study. Subjects with confirmed diagnosis of dry eye are randomly assigned to control group or treatment group, and asked to orally intake 1 capsule of either placebo or probiotics per day. All participants will be assessed for parameters, including intraocular pressure, ocular surface health, tear film breakup time (TBUT), tear volume (Schirmer's test), tear osmolarity, ocular surface impression cytology, ocular surface disease index (OSDI) and serum biochemical tests for quantification of hyaluronic acid, sialic acid, glutathione contents.The assessments are conducted at day1 for baseline and after the 35-day oral intake. The parameters are used to compare and evaluate whether the probiotics can relieve dry eye symptoms.

Study Type

Interventional

Enrollment (Actual)

88

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: David Pei-Cheng Lin
  • Phone Number: 886-910-371286
  • Email: pcl@csmu.edu.tw

Study Contact Backup

Study Locations

      • Taichung, Taiwan, 412
        • Jen-Ai Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • aged between 20 and 65 years
  • with Schirmer's test results less than 10 mm or Ocular Surface Disease Index more than 25

Exclusion Criteria:

  • evident ocular diseases such as cornea disease, cataract, vitreous degeneration, glaucoma, and retinopathy.
  • diabetes
  • hypertension
  • or other chronic diseases or belong to vulnerable groups(pregnancy woman, prisoner, ethical minorities, economic or educationally disadvantaged subjects, disabled individuals such as those at terminal stage of tumorigenesis, blindness, terminal ill individuals)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Control group
Subjects will take a capsule of containing microcrystalline cellulose per day for 35 days.
A specific capsule product, containing microcrystalline cellulose will be given to participants for oral intake for 35 days.
Experimental: Treatment group
Subjects will take a capsule of containing Streptococcus thermophilus per day for 35 days.
A specific probiotics capsule product, containing Streptococcus thermophilus will be given to participants for oral intake for 35 days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change of Schirmer's Test Value from Baseline
Time Frame: on baseline and day36
The Schirmer's Test is used to assess tear secretion volume. The amounts of tears are measured in total millimeters after 5 minutes has elapsed. Lower measurement amount is regarded as a parameter of presence of dry eye disease.
on baseline and day36
Change of Tear Film Breakup Time from Baseline
Time Frame: on baseline and day36
Tear Break-Up Time is a measurement to reflect tear quality and is expressed in seconds. The shorter the Tear Break-Up Time, the poorer the tear film stability and quality. Lower measurement outcome (less than 10 seconds) is regarded as a parameter of presence of dry eye disease.
on baseline and day36
Ocular Surface Index Change from Baseline
Time Frame: on baseline and day36
Ocular Surface Index is assessed with fluorescein staining to reflect ocular surface damages. The staining scale ranges from 0 to 3, from milder to severe status, where grade 0 shows no staining, and grade 3 shows extensive staining.
on baseline and day36
Tear Osmolality Change from Baseline
Time Frame: on baseline and day36
Tear osmolality is used as a parameter of dry eye status.
on baseline and day36
Serum Biochemical Test
Time Frame: on baseline and day36
To determine the effects of oral probiotics intake on the contents of hyaluronic acid, sialic acid, and glutathione in the serum.
on baseline and day36

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Ocular Surface Impression Cytology Change from Baseline
Time Frame: on baseline and day36
To assess the status of conjunctival goblet cells and epithelium.
on baseline and day36
Ocular Surface Disease Index Score Change from Baseline
Time Frame: on baseline and day36
A questionnaire is used to assess the health status on ocular surface, with higher scores indicating more severe status.
on baseline and day36
Intraocular Pressure Change from Baseline
Time Frame: on baseline and day36
To determine the effects of intervention on intraocular pressure.
on baseline and day36

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Collaborators

Investigators

  • Principal Investigator: David Pei-Cheng Lin, Chung Shan Medical University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 13, 2023

Primary Completion (Actual)

August 31, 2023

Study Completion (Actual)

December 31, 2023

Study Registration Dates

First Submitted

May 19, 2023

First Submitted That Met QC Criteria

June 14, 2023

First Posted (Actual)

June 15, 2023

Study Record Updates

Last Update Posted (Estimated)

September 26, 2025

Last Update Submitted That Met QC Criteria

September 24, 2025

Last Verified

June 1, 2023

More Information

Terms related to this study

Other Study ID Numbers

  • 202300014B0

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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