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NCT Number: NCT05906381

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.

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Key information

Conditions

Dry Eye Asthenopia Dry Eye Syndromes Eye Diseases Lacrimal Apparatus Diseases

Age range

20 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Jen-Ai Hospital

Taichung, 412, Taiwan

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Probiotics

Dietary Supplement

A specific probiotics capsule product, containing Streptococcus thermophilus will be given to participants for oral intake for 35 days.

Placebo

Dietary Supplement

A specific capsule product, containing microcrystalline cellulose will be given to participants for oral intake for 35 days.

Primary outcomes

  1. 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.

  2. 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.

  3. 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.

  4. Tear Osmolality Change from Baseline

    Time frame: on baseline and day36

    Tear osmolality is used as a parameter of dry eye status.

  5. 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.

Secondary outcomes

  1. Ocular Surface Impression Cytology Change from Baseline

    Time frame: on baseline and day36

    To assess the status of conjunctival goblet cells and epithelium.

  2. 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.

  3. Intraocular Pressure Change from Baseline

    Time frame: on baseline and day36

    To determine the effects of intervention on intraocular pressure.

Sponsors and collaborators

Lead sponsor

Chung Shan Medical University

Other

Collaborators

  • Nutrarex Biotech Co., Ltd.

Registry information

Official study title

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

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
Jun 15, 2023
Registry last updated
Sep 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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