Dry EyeNCT07148271
Effect of a Dietary Supplement on Gut Microbiota and Ocular Surface Outcomes in Dry Eye Disease
A study testing Dietary Supplement Product in people with Dry Eye and Meibomian Gland Dysfunction (Disorder), run by Varol TUNALI at 1 site in Turkey (Türkiye).
Trial summary
This prospective clinical study investigates whether a dietary supplement product can modulate the gut microbiota and improve ocular surface outcomes in patients with dry eye disease. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Dry Eye, Meibomian Gland Dysfunction (Disorder), Dry Eye Disease (DED)
- What is being tested?
- Dietary Supplement Product
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Oct 2025to 15 Mar 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18-65 years.
- Clinical diagnosis of dry eye disease with clinically significant symptoms, defined as Ocular Surface Disease Index (OSDI) score ≥23 at screening and/or baseline.
- Evidence of tear film instability consistent with dry eye disease, defined as fluorescein tear break-up time (TBUT) ≤10 seconds in at least one eye at screening and/or baseline.
- Willing and able to provide written informed consent.
- Willing to maintain habitual diet and lifestyle during the study period and to avoid initiating new microbiome-active products (e.g., probiotic/prebiotic/synbiotic supplements) during the intervention.
Who cannot join
- Current restrictive dietary pattern likely to materially alter gut microbiota (e.g., ketogenic diet, elimination diets, prolonged fasting) or planned major dietary change during the study period.
- Colonoscopy within the past 4 weeks.
- Systemic antibiotic use within the past 4 weeks.
- Use of probiotic, prebiotic, synbiotic, postbiotic, or fecal microbiota-related products within the past 4 weeks.
- Active ocular infection or acute ocular inflammation requiring treatment escalation (e.g., acute blepharitis flare, active allergic conjunctivitis requiring escalation), at screening/baseline.
- Sjögren syndrome or other active systemic autoimmune disease with clinically significant ocular involvement, in the investigator's judgment.
Show all 12Show fewer
- Ocular surgery (including refractive surgery) or significant ocular trauma within the past 6 months.
- Contact lens wear within 30 days prior to baseline or planned contact lens use during the study.
- Topical cyclosporine, lifitegrast, or topical ocular corticosteroid use within 8-12 weeks prior to baseline, or planned initiation during the study.
- Punctal plug placement within the past 3 months or planned during the study.
- Known hypersensitivity to any component of the study product.
- Any other systemic or ocular condition that, in the investigator's judgment, could compromise participant safety or interfere with study outcomes.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Prospective Study Evaluating the Effects of a Dietary Supplement Product on Gut Microbiota and Ocular Surface Parameters in Patients With Dry Eye Disease
This prospective clinical study investigates whether a dietary supplement product can modulate the gut microbiota and improve ocular surface outcomes in patients with dry eye disease. Participants will be recruited from Istanbul Medipol University Hospital (Department of Ophthalmology) and Liv Hospitals (Vadi Istanbul and Ulus). Each participant will receive the dietary supplement product for 8 weeks. Gut microbiota analyses will be conducted at baseline and week 8. Ocular surface assessments including Schirmer test and invasive tear breakup time (TBUT) will be performed at baseline and week 8.
Read the detailed description
Dry eye disease (DED) is a multifactorial ocular surface disorder characterized by chronic tear film instability, hyperosmolarity, and ocular surface inflammation. It represents one of the most common reasons for ophthalmology consultations worldwide and has a profound impact on patient quality of life. Conventional treatment approaches primarily target symptoms and tear film supplementation, but disease-modifying interventions remain limited.
Emerging evidence suggests that the gut microbiota exerts systemic immunomodulatory effects, influencing diseases beyond the gastrointestinal tract, including ocular conditions. Dysbiosis has been implicated in autoimmune, metabolic, and inflammatory disorders, and a growing body of literature indicates that the gut-eye axis may play a role in the pathogenesis of DED. Specific microbiota-derived metabolites, microbial antigens, and immune pathways are believed to modulate ocular surface inflammation and tear film stability. This provides a strong rationale for exploring microbiome-targeted interventions in DED.
This single-arm, prospective interventional trial investigates the impact of an 8-week course of a defined dietary supplement product on gut microbiota composition and diversity, alongside established ocular surface clinical endpoints. Participants will be recruited from Istanbul Medipol University Hospital (Department of Ophthalmology) and Liv Hospitals (Vadi Istanbul and Ulus). All enrolled patients will receive the dietary supplement once daily for the study duration.
Microbiome assessment: Stool samples will be collected at baseline and at week 8, with DNA extraction followed by metagenomic sequencing. Microbiota analysis will focus on alpha diversity (e.g., Shannon index) and taxonomic/functional profiling to detect shifts in microbial composition associated with the intervention.
Ophthalmological assessment: Clinical evaluations will be performed at baseline and at week 8, including the Schirmer test, invasive tear breakup time (TBUT), Ocular Surface Disease Index (OSDI), and Dry Eye Scoring System (DESS). These standardized measures provide quantitative and qualitative assessment of tear production, stability, and patient-reported symptoms.
Safety and adherence: Safety monitoring will include the recording of adverse events throughout the trial, with particular attention to potential gastrointestinal or ocular side effects. Adherence will be assessed through participant reporting and calculation of percentage of doses taken.
Statistical considerations: Data will be analyzed using SPSS v22.0. As this is a single-arm, within-subject study, changes over time will be evaluated using one-way repeated-measures analysis of variance (ANOVA) when distributional assumptions are met. Effect sizes will be reported as partial eta squared (η²p). When a significant main effect of time is detected, post-hoc pairwise comparisons will be performed with Bonferroni correction. Descriptive statistics will be used to summarize adherence and adverse events.
This study aims to provide mechanistic insights into the gut-eye axis by linking microbiome modulation with ocular surface outcomes. Although exploratory in design, the findings may lay the groundwork for future randomized controlled trials evaluating microbiome-targeted interventions as adjunctive therapy for DED.
- Conditions
- Dry Eye, Meibomian Gland Dysfunction (Disorder), Dry Eye Disease (DED), Dry Eye Disease, Meibomian Gland Disease
- Being tested
- Dietary Supplement Product
- Keywords
- Dry eye disease, Meibomian gland dysfunction, Food supplement, Gut microbiome, Gut eye axis
- Medical subject headings
- Dry Eye Syndromes, Meibomian Gland Dysfunction
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary Supplement ProductDietary supplement
Participants will receive a dietary supplement product administered orally once daily for 8 weeks. The supplement is provided in sachet form and taken with water. The intervention is designed to modulate gut microbiota composition and diversity, with the potential to influence ocular surface outcomes in patients with dry eye disease. The regimen will be self-administered at home, with adherence monitored at study visits. Stool samples will be collected at baseline and week 8 for metagenomic sequencing, and ocular surface parameters will be assessed at the same time points. Safety will be evaluated by monitoring for adverse events throughout the intervention period.
| Study group | Role | What they receive |
|---|---|---|
| Intervention arm | Experimental | Not described Receives: Dietary Supplement: Dietary Supplement Product |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Schirmer Test Score
Tear production will be assessed using the Schirmer Test without anesthesia at baseline and at week 8. Standardized Schirmer paper strips will be placed in the lower eyelid, and the length of strip wetting (measured in millimeters) will be recorded after 5 minutes.
The Schirmer Test yields values ranging from 0 mm (no tear production) to approximately 35 mm (normal/high tear production) over 5 minutes. Higher values represent better tear production, while values <10 mm/5 min are commonly associated with clinically significant dry eye disease.
The primary endpoint is the mean change in Schirmer Test score from baseline to week 8 and from baseline to Week 16 (Follow-up).
Measured: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Secondary outcomes (4)
Change in Tear Breakup Time (TBUT, invasive)
Tear film stability will be assessed at baseline and week 8 using the Fluorescein Tear Breakup Time Test. After instillation of fluorescein dye into the tear film, the time (in seconds) between a complete blink and the appearance of the first dry spot on the cornea will be recorded. TBUT values typically range from 0 seconds (immediate breakup, very unstable tear film) to >10 seconds (normal tear film stability). Shorter TBUT values indicate worse tear film stability and more severe dry eye disease.
Measured: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in Ocular Surface Disease Index (OSDI)
The Ocular Surface Disease Index (OSDI) questionnaire will be administered at baseline and week 8. The OSDI consists of 12 items evaluating ocular discomfort, vision-related function, and environmental triggers. Scores range from 0 to 100, where 0 indicates no symptoms and 100 indicates the most severe dry eye symptoms. Higher scores represent worse outcomes.
Measured: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in Dry Eye Questionnaire-5 (DEQ-5)
The Dry Eye Questionnaire-5 (DEQ-5) will be administered at baseline, Week 8, and Week 16 to assess the severity and frequency of dry eye symptoms. The DEQ-5 consists of five items evaluating ocular discomfort and dryness. Total scores range from 0 (no symptoms) to 22 (maximum severity and frequency of symptoms). Higher scores indicate more severe dry eye symptoms and worse outcomes.
Measured: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in gut microbiota diversity (Shannon index)
Stool samples will be collected at baseline and week 8 for 16S rRNA amplicon sequencing. Alpha diversity will be measured using the Shannon Diversity Index, which accounts for both richness and evenness of microbial communities. Shannon index values are non-negative and typically range from 0 (no diversity) to approximately 5-6 (very high diversity in complex communities). Higher Shannon index values represent greater microbial diversity, which is generally considered a favorable outcome.
Measured: From enrollment to the end of treatment at 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Aug 2025
- Study start1 Oct 2025
- Primary completion20 Feb 2026
- Study completion15 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Dry EyeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- Varol TUNALI
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Istanbul Medipol University Hospital, Liv Hospital (Ulus)
- Responsible party
- Sponsor-investigator, Varol TUNALI, ENBIOSIS BIOTECHNOLOGIES
- Investigators
- Varol TUNALI, Dr., Principal investigator, Celal Bayar University Faculty of Medicine Parasitology Department
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07148271
- Sponsor's protocol ID
- E-10840098-202.3.02-444
- Status last verified
- Feb 2026
- First submitted
- 22 Aug 2025
- Last updated
- 6 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Individual participant data (IPD) that underlie the results reported in this study (after de-identification) will be made available to researchers upon reasonable request. Data to be shared include demographic variables, outcome measures (ocular surface parameters, microbiome sequencing data, and safety/adherence data), and relevant baseline characteristics. A data dictionary will be provided to allow full interpretation. The data will become available following publication of the primary study results and will be accessible for a period of 5 years thereafter. Researchers may request access by contacting the principal investigator. Requests will be evaluated on a case-by-case basis, and data will be shared for scientifically valid proposals in accordance with ethical approvals and data protection regulations.
Study at a glance
From the registry record, last updated by the sponsor on 6 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective Study Evaluating the Effects of a Dietary Supplement Product on Gut Microbiota and Ocular Surface Parameters in Patients With Dry Eye Disease
- ClinicalTrials.gov ID
- NCT07148271
- Acronym / sponsor ID
- E-10840098-202.3.02-444
- Conditions
- Dry Eye, Meibomian Gland Dysfunction (Disorder), Dry Eye Disease (DED), Dry Eye Disease, Meibomian Gland Disease
- Keywords
- Dry eye disease, Meibomian gland dysfunction, Food supplement, Gut microbiome, Gut eye axis
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- Varol TUNALIIndustry (pharma, biotech, devices)
- Collaborators
- Istanbul Medipol University Hospital, Liv Hospital (Ulus)
- Study start
- 1 Oct 2025 (actual)
- Primary completion
- 20 Feb 2026 (actual)
- Study completion
- 15 Mar 2026 (actual)
- First posted
- 29 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective clinical study investigates whether a dietary supplement product can modulate the gut microbiota and improve ocular surface outcomes in patients with dry eye disease. Participants will be recruited from Istanbul Medipol University Hospital (Department of Ophthalmology) and Liv Hospitals (Vadi Istanbul and Ulus). Each participant will receive the dietary supplement product for 8 weeks. Gut microbiota analyses will be conducted at baseline and week 8. Ocular surface assessments including Schirmer test and invasive tear breakup time (TBUT) will be performed at baseline and week 8.
Detailed description
Dry eye disease (DED) is a multifactorial ocular surface disorder characterized by chronic tear film instability, hyperosmolarity, and ocular surface inflammation. It represents one of the most common reasons for ophthalmology consultations worldwide and has a profound impact on patient quality of life. Conventional treatment approaches primarily target symptoms and tear film supplementation, but disease-modifying interventions remain limited.
Emerging evidence suggests that the gut microbiota exerts systemic immunomodulatory effects, influencing diseases beyond the gastrointestinal tract, including ocular conditions. Dysbiosis has been implicated in autoimmune, metabolic, and inflammatory disorders, and a growing body of literature indicates that the gut-eye axis may play a role in the pathogenesis of DED. Specific microbiota-derived metabolites, microbial antigens, and immune pathways are believed to modulate ocular surface inflammation and tear film stability. This provides a strong rationale for exploring microbiome-targeted interventions in DED.
This single-arm, prospective interventional trial investigates the impact of an 8-week course of a defined dietary supplement product on gut microbiota composition and diversity, alongside established ocular surface clinical endpoints. Participants will be recruited from Istanbul Medipol University Hospital (Department of Ophthalmology) and Liv Hospitals (Vadi Istanbul and Ulus). All enrolled patients will receive the dietary supplement once daily for the study duration.
Microbiome assessment: Stool samples will be collected at baseline and at week 8, with DNA extraction followed by metagenomic sequencing. Microbiota analysis will focus on alpha diversity (e.g., Shannon index) and taxonomic/functional profiling to detect shifts in microbial composition associated with the intervention.
Ophthalmological assessment: Clinical evaluations will be performed at baseline and at week 8, including the Schirmer test, invasive tear breakup time (TBUT), Ocular Surface Disease Index (OSDI), and Dry Eye Scoring System (DESS). These standardized measures provide quantitative and qualitative assessment of tear production, stability, and patient-reported symptoms.
Safety and adherence: Safety monitoring will include the recording of adverse events throughout the trial, with particular attention to potential gastrointestinal or ocular side effects. Adherence will be assessed through participant reporting and calculation of percentage of doses taken.
Statistical considerations: Data will be analyzed using SPSS v22.0. As this is a single-arm, within-subject study, changes over time will be evaluated using one-way repeated-measures analysis of variance (ANOVA) when distributional assumptions are met. Effect sizes will be reported as partial eta squared (η²p). When a significant main effect of time is detected, post-hoc pairwise comparisons will be performed with Bonferroni correction. Descriptive statistics will be used to summarize adherence and adverse events.
This study aims to provide mechanistic insights into the gut-eye axis by linking microbiome modulation with ocular surface outcomes. Although exploratory in design, the findings may lay the groundwork for future randomized controlled trials evaluating microbiome-targeted interventions as adjunctive therapy for DED.
Study design
- Primary purpose
- Supportive care
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Intervention arm | Experimental | Dietary Supplement: Dietary Supplement Product |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adults aged 18-65 years.
- Clinical diagnosis of dry eye disease with clinically significant symptoms, defined as Ocular Surface Disease Index (OSDI) score ≥23 at screening and/or baseline.
- Evidence of tear film instability consistent with dry eye disease, defined as fluorescein tear break-up time (TBUT) ≤10 seconds in at least one eye at screening and/or baseline.
- Willing and able to provide written informed consent.
- Willing to maintain habitual diet and lifestyle during the study period and to avoid initiating new microbiome-active products (e.g., probiotic/prebiotic/synbiotic supplements) during the intervention.
Key exclusion criteria (12 listed)
- Current restrictive dietary pattern likely to materially alter gut microbiota (e.g., ketogenic diet, elimination diets, prolonged fasting) or planned major dietary change during the study period.
- Colonoscopy within the past 4 weeks.
- Systemic antibiotic use within the past 4 weeks.
- Use of probiotic, prebiotic, synbiotic, postbiotic, or fecal microbiota-related products within the past 4 weeks.
- Active ocular infection or acute ocular inflammation requiring treatment escalation (e.g., acute blepharitis flare, active allergic conjunctivitis requiring escalation), at screening/baseline.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dietary Supplement ProductParticipants will receive a dietary supplement product administered orally once daily for 8 weeks. The supplement is provided in sachet form and taken with water. The intervention is designed to modulate gut microbiota composition and diversity, with the potential to influence ocular surface outcomes in patients with dry eye disease. The regimen will be self-administered at home, with adherence monitored at study visits. Stool samples will be collected at baseline and week 8 for metagenomic sequencing, and ocular surface parameters will be assessed at the same time points. Safety will be evaluated by monitoring for adverse events throughout the intervention period. | Dietary supplement | Intervention arm |
Primary outcome
Change in Schirmer Test Score
Time frame: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Tear production will be assessed using the Schirmer Test without anesthesia at baseline and at week 8. Standardized Schirmer paper strips will be placed in the lower eyelid, and the length of strip wetting (measured in millimeters) will be recorded after 5 minutes. The Schirmer Test yields values ranging from 0 mm (no tear production) to approximately 35 mm (normal/high tear production) over 5 minutes. Higher values represent better tear production, while values <10 mm/5 min are commonly associated with clinically significant dry eye disease. The primary endpoint is the mean change in Schirmer Test score from baseline to week 8 and from baseline to Week 16 (Follow-up).
4 secondary outcomes
Change in Tear Breakup Time (TBUT, invasive)
Time frame: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in Ocular Surface Disease Index (OSDI)
Time frame: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in Dry Eye Questionnaire-5 (DEQ-5)
Time frame: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)
Change in gut microbiota diversity (Shannon index)
Time frame: From enrollment to the end of treatment at 8 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Oct 2026.
- Individual participant dataSharing planned: Yes. Individual participant data (IPD) that underlie the results reported in this study (after de-identification) will be made available to researchers upon reasonable request. Data to be shared include demographic variables, outcome measures (ocular surface parameters, microbiome sequencing data, and safety/adherence data), and relevant baseline characteristics. A data dictionary will be provided to allow full interpretation. The data will become available following publication of the primary study results and will be accessible for a period of 5 years thereafter. Researchers may request access by contacting the principal investigator. Requests will be evaluated on a case-by-case basis, and data will be shared for scientifically valid proposals in accordance with ethical approvals and data protection regulations.
Related trials for Dry Eye
Not yet recruitingPhase 1
R-2487 in Patients With Sjogren's Syndrome (SjD)
Sjogren's Syndrome, Sjögren
RecruitingPhase 1
A Trial in Healthy Adult Participants and Adults With Autoimmune Diseases to Test How HBM7020 is Tolerated and How it Behaves in the Body
Rheumatoid Arthritis, Systemic Lupus Erythematosus
RecruitingObservational study
Pain Phenotyping of Rheumatic Diseases - An Observational Study
Rheumatic Diseases, Lupus Erythematosus, Systemic
RecruitingPhase 1/2
Autologous Transplantation of Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium for Geographic Atrophy Associated With Age-Related Macular Degeneration
Dry Age-Related Macular Degeneration, Geographic Atrophy
RecruitingObservational study
The Pathogenesis and Natural History of Sjogren's Disease
Sjogren's Syndrome, Salivary Gland
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Varol TUNALI, Dr. principal investigator
Celal Bayar University Faculty of Medicine Parasitology Department
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dietary Supplement Product in people with Dry Eye and Meibomian Gland Dysfunction (Disorder), run by Varol TUNALI at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Schirmer Test Score (time frame: Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Oct 2026.