Effect of a Dietary Supplement on Gut Microbiota and Ocular Surface Outcomes in Dry Eye Disease

NCT07148271 | Completed

• 1 other identifier: E-10840098-202.3.02-444
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief 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. 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.

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

Outcome Measures

Primary Outcomes (1)

• 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).

  Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)

Secondary Outcomes (4)

• Change in Tear Breakup Time (TBUT, invasive)

  Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)

• Change in Ocular Surface Disease Index (OSDI)

  Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)

• Change in Dry Eye Questionnaire-5 (DEQ-5)

  Baseline to Week 8 (Treatment End) and Baseline to Week 16 (Follow-up)

• Change in gut microbiota diversity (Shannon index)

  From enrollment to the end of treatment at 8 weeks

Study Arms (1)

Intervention arm

EXPERIMENTAL

Dietary Supplement: Dietary Supplement Product

Interventions

Dietary Supplement Product DIETARY_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.

Intervention arm

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• Varol TUNALI: lead
• Istanbul Medipol University Hospital: collaborator
• Liv Hospital (Ulus): collaborator

Study Sites (1)

Medipol University

Istanbul, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Dry Eye Syndromes; Meibomian Gland Dysfunction

Condition Hierarchy (Ancestors)

Lacrimal Apparatus Diseases; Eye Diseases; Eyelid Diseases

Study Officials

• Varol TUNALI, Dr.

  Celal Bayar University Faculty of Medicine Parasitology Department

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Doctor

Study Record Dates

• First Submitted: August 22, 2025
• First Posted: August 29, 2025
• Study Start: October 1, 2025
• Primary Completion: December 20, 2025
• Study Completion: January 15, 2026
• Last Updated: February 18, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: May 2026-May 2031

Locations

TU (1)