Impact of GLP-1 Receptor Agonists on Dry Eye Disease in Patients With Type 2 Diabetes Mellitus and Obesity (GALENOS)

May 29, 2026 updated by: VAIA LAMBADIARI, Attikon Hospital
Diabetes mellitus (DM), prediabetes, and obesity are emerging as major global public health problems, with their epidemic spread continuously increasing over the past decades. The occurrence of diabetic retinopathy, cataract, glaucoma, and ocular surface disease in patients with diabetes mellitus has been extensively investigated in several studies. However, mild ocular surface disorders, such as dry eye disease, have often been overlooked, with a previous study showing that 51.3% of diabetes-related dry eye disease cases remained underdiagnosed. Among systemic diseases, diabetes mellitus and obesity have been associated with an increased risk of developing dry eye disease. Chronic hyperglycemia in diabetes leads to microvascular damage, including corneal neuropathy and reduced tear production, conditions that can disrupt ocular surface health, while systemic inflammation and meibomian gland dysfunction also contribute to this process. However, the effect of newer classes of antidiabetic medications, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs), on ocular surface health remains insufficiently understood. The aim of this prospective cohort study is to evaluate the effects of GLP-1 receptor agonists on dry eye disease in patients with type 2 diabetes mellitus and obesity through the assessment of ocular surface parameters, such as tear film break-up time, Schirmer test results, as well as potential changes in corneal topography.

Study Overview

Status

Recruiting

Conditions

Detailed Description

This prospective cohort study aims to shed a light to the effects of GLP-1 RAs on Dry Eye Disease in Patients with Type 2 Diabetes Mellitus and Obesity.

Study Type

Observational

Enrollment (Estimated)

100

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

Study Locations

  • Greece
      • Athens, Greece, 12462
        • Recruiting
        • 2nd Department of Internal Medicine, Research Institute and Diabetes Center, National and Kapodistrian University of Athens, Athens, GRC.
        • Contact:

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

Sampling Method

Non-Probability Sample

Study Population

The diagnosis of diabetes mellitus will be established according to the diagnostic criteria defined by the European Association for the Study of Diabetes (EASD), the American Diabetes Association (ADA), and the European Association for the Study of Obesity (EASO).

Male and/or female patients attending the regular outpatient ophthalmology clinics, with stable refraction over the past two years, without pathological corneal findings (including corneal ulcer, keratoconus, corneal dystrophies, corneal trauma/abrasions), no history of corneal infections during the last 2 years, and no history of refractive surgery will be included.

To ensure the objectivity of the results, the assessment of dry eye disease parameters will be performed by an ophthalmologist blinded to the patient's study group allocation (single-blinded design), thereby minimizing the possibility of observer bias during data collection.

Description

Inclusion Criteria:

  1. Age ≥18 years.
  2. Patients who have not previously received GLP-1 receptor agonists (GLP-1 RAs).
  3. Patients able to provide informed consent for participation in the study.

Exclusion Criteria:

  1. Pregnant or breastfeeding patients.
  2. History of multiple severe hypoglycemic episodes within the past two years.
  3. Active intraocular inflammation in either eye, such as infectious conjunctivitis, keratitis, scleritis, endophthalmitis, or autoimmune uveitis.
  4. Patients who have undergone cataract surgery or vitrectomy within the past 6 months.
  5. History of ketoacidosis or metabolic acidosis.
  6. History of corneal transplantation.

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

Cohorts and Interventions

Group / Cohort
Group A
50 patients who will receive GLP-1 RAs (Semaglutide) therapy for overweight/obesity, with or without type 2 diabetes mellitus.
Group B
50 individuals who will be included in the control group and will not receive GLP-1 RA therapy, matched for age, sex, and BMI.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in Ocular Parameters
Time Frame: All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.
Change in Best-Corrected Visual Acuity (BCVA): Assessment of changes in best-corrected visual acuity (BCVA) using standardized Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity charts.
All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Tear Film Break-Up Time (BUT)
Time Frame: All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.
Change in Tear Film Break-Up Time (BUT): Assessment of changes from baseline in tear film break-up time (BUT), measured in seconds (s), as an indicator of tear film stability and ocular surface function.
All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.
Change in Tear Meniscus Height (TMH)
Time Frame: All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.
Change in Tear Meniscus Height (TMH): Assessment of changes from baseline in tear meniscus height (TMH), measured in millimeters (mm), as an indicator of tear volume and ocular surface function.
All ophthalmological will be assessed at two time points: t0: Baseline assessment, before initiation of GLP-1 RA or GLP-1 RA/GIP therapy. t1: Follow-up assessment, 6-months after the intervention period, to evaluate changes ocular surface.

Collaborators and Investigators

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

Sponsor

Attikon Hospital

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.

General Publications

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)

March 1, 2026

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

February 28, 2027

Study Registration Dates

First Submitted

May 11, 2026

First Submitted That Met QC Criteria

May 18, 2026

First Posted (Actual)

May 26, 2026

Study Record Updates

Last Update Posted (Actual)

June 2, 2026

Last Update Submitted That Met QC Criteria

May 29, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 193-16/02/2026

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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