Ocular Changes in Patients Using Tirzepatide or Semaglutide

November 3, 2026 updated by: Derya Budak Behrad, Istanbul University

Evaluation of Optic Nerve Head, Retinal Changes, and Choroidal Blood Flow in Patients With Diabetes and Obesity Using Tirzepatide or Semaglutide

This prospective observational study aims to evaluate ocular structural and microvascular changes in adults with obesity who are receiving semaglutide or tirzepatide as part of routine clinical care. Participants with and without type 2 diabetes mellitus will be included.

Participants will undergo ophthalmologic examinations at baseline and during follow-up. Changes in optic nerve head parameters, retinal thickness, retinal and choroidal microvascular parameters, and choroidal thickness will be assessed using optical coherence tomography (OCT), optical coherence tomography angiography (OCT-A), and other routine ophthalmologic examination methods.

The study will compare ocular measurements obtained at baseline and during follow-up to investigate changes associated with semaglutide or tirzepatide treatment over a period of up to 18 months.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This prospective observational cohort study will evaluate ocular structural and microvascular changes in adults with obesity receiving semaglutide or tirzepatide as part of routine clinical care. Participants will include individuals with and without type 2 diabetes mellitus.

The study population will be divided into four observational cohorts according to diabetes status and medication use:

  • Participants with obesity and type 2 diabetes receiving semaglutide.
  • Participants with obesity and type 2 diabetes receiving tirzepatide.
  • Participants with obesity without type 2 diabetes receiving semaglutide.
  • Participants with obesity without type 2 diabetes receiving tirzepatide.

Participants will undergo ophthalmologic examinations at baseline and during follow-up for up to 18 months. Assessments will include visual acuity, slit-lamp examination, intraocular pressure measurement, fundus examination, optical coherence tomography (OCT), optical coherence tomography angiography (OCT-A), and enhanced depth imaging optical coherence tomography (EDI-OCT).

The study will evaluate changes in retinal nerve fiber layer thickness, retinal thickness, superficial and deep retinal vessel density, foveal avascular zone area, choriocapillaris flow deficit percentage, and choroidal thickness. Changes in visual acuity and intraocular pressure will also be assessed.

Ocular measurements obtained at baseline and during follow-up will be compared to investigate structural and microvascular changes associated with semaglutide or tirzepatide treatment. Differences between the observational cohorts may also be evaluated.

All medications will be prescribed by the treating physicians as part of routine clinical care. Treatment selection will not be determined by the study protocol, and no experimental ophthalmologic intervention will be performed.

Study Type

Observational

Enrollment (Estimated)

40

Contacts and Locations

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

Study Locations

  • Turkey (Türkiye)
    • Istanbul
      • Istanbul, Istanbul, Turkey (Türkiye), 34093
        • Recruiting
        • Istanbul University, Istanbul Faculty of Medicine
        • Contact:
        • Contact:
          • ADEM TELLIOGLU, MD
          • Phone Number: +90 5066107361

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Adults with obesity who are receiving semaglutide or tirzepatide as part of routine clinical care will be included. Participants will include individuals with and without type 2 diabetes mellitus. The study population will be evaluated in four observational cohorts according to diabetes status and medication: obesity with diabetes receiving semaglutide, obesity with diabetes receiving tirzepatide, obesity without diabetes receiving semaglutide, and obesity without diabetes receiving tirzepatide.

Description

Inclusion Criteria:

  • Age 18 years or older
  • Diagnosis of obesity
  • Receiving semaglutide or tirzepatide as part of routine clinical care
  • Participants with or without type 2 diabetes mellitus
  • Availability for baseline and follow-up ophthalmologic examinations

Exclusion Criteria:

  • Age under 18 years
  • Not receiving semaglutide or tirzepatide
  • Inability to complete the required ophthalmologic examinations or imaging assessments

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

  • Observational Models: COHORT
  • Time Perspectives: PROSPECTIVE

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Obesity With Diabetes - Semaglutide

Participants with obesity and diabetes receiving semaglutide as part of routine clinical care.
Drug: Semaglutide

Semaglutide is prescribed as part of routine clinical care. Treatment is not assigned by the study protocol. Ocular structural and vascular parameters are evaluated before treatment and during follow-up.
Obesity With Diabetes - Tirzepatide

Participants with obesity and diabetes receiving tirzepatide as part of routine clinical care
Drug: Tirzepatide

Tirzepatide is prescribed as part of routine clinical care. Treatment is not assigned by the study protocol. Ocular structural and vascular parameters are evaluated before treatment and during follow-up.
Obesity Without Diabetes - Semaglutide

Participants with obesity without diabetes receiving semaglutide as part of routine clinical care
Drug: Semaglutide

Semaglutide is prescribed as part of routine clinical care. Treatment is not assigned by the study protocol. Ocular structural and vascular parameters are evaluated before treatment and during follow-up.
Obesity Without Diabetes - Tirzepatide

Participants with obesity without diabetes receiving tirzepatide as part of routine clinical care
Drug: Tirzepatide

Tirzepatide is prescribed as part of routine clinical care. Treatment is not assigned by the study protocol. Ocular structural and vascular parameters are evaluated before treatment and during follow-up.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Retinal Nerve Fiber Layer Thickness
Time Frame: Baseline to up to 18 months

Change in retinal nerve fiber layer thickness from baseline during follow-up, assessed using optical coherence tomography (OCT).
Baseline to up to 18 months
Change in Retinal Thickness
Time Frame: Baseline to up to 18 months

Change in retinal thickness from baseline during follow-up, assessed using optical coherence tomography (OCT).
Baseline to up to 18 months
Change in Superficial Retinal Vessel Density
Time Frame: Baseline to 18 months

Change in superficial retinal capillary vessel density from baseline to follow-up, assessed using optical coherence tomography angiography (OCT-A) and expressed as a percentage (%).
Baseline to 18 months
Change in Deep Retinal Vessel Density
Time Frame: Baseline to 18 months

Change in deep retinal capillary vessel density from baseline to follow-up, assessed using optical coherence tomography angiography (OCT-A) and expressed as a percentage (%).
Baseline to 18 months
Change in Foveal Avascular Zone Area
Time Frame: Baseline to 18 months

Change in foveal avascular zone (FAZ) area from baseline to follow-up, measured using optical coherence tomography angiography (OCT-A) and expressed in square millimeters (mm²).
Baseline to 18 months
Change in Choriocapillaris Flow Deficit Percentage
Time Frame: Baseline to 18 months

Change in choriocapillaris flow deficit percentage from baseline to follow-up, assessed using optical coherence tomography angiography (OCT-A) and expressed as a percentage (%).
Baseline to 18 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Visual Acuity
Time Frame: Baseline to up to 18 months

Change in visual acuity from baseline during follow-up
Baseline to up to 18 months
Change in Intraocular Pressure
Time Frame: Baseline to up to 18 months

Change in intraocular pressure from baseline during follow-up, measured in mmHg during routine ophthalmologic examination.
Baseline to up to 18 months

Collaborators and Investigators

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

Sponsor

Istanbul University

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)

September 17, 2027

Study Completion (Estimated)

September 17, 2027

Study Registration Dates

First Submitted

October 28, 2026

First Submitted That Met QC Criteria

November 3, 2026

First Posted (Actual)

November 9, 2026

Study Record Updates

Last Update Posted (Actual)

November 9, 2026

Last Update Submitted That Met QC Criteria

November 3, 2026

Last Verified

October 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025/2444

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

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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