An observational study in Type 2 Diabetes Mellitus and Obesity, sponsored by Istanbul University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-09.
Sponsored by Istanbul University · Observational
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.
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 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.
10,371 studies on the registry are indexed under Diabetes Mellitus, Type 2; 1,406 are open to participants now.
This study's planned enrollment of 40 is below the median of 300 across 1,741 observational studies indexed under Diabetes Mellitus, Type 2.
Browse Diabetes Mellitus, Type 2 studies →Istanbul University is the lead sponsor of 511 studies on the registry; 78 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 1 (20%) have results posted.
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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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participants with obesity and diabetes receiving semaglutide as part of routine clinical care.
Drug: Semaglutide
Participants with obesity and diabetes receiving tirzepatide as part of routine clinical care
Drug: Tirzepatide
Participants with obesity without diabetes receiving semaglutide as part of routine clinical care
Drug: Semaglutide
Participants with obesity without diabetes receiving tirzepatide as part of routine clinical care
Drug: Tirzepatide
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.
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.
Change in Retinal Nerve Fiber Layer Thickness
Change in retinal nerve fiber layer thickness from baseline during follow-up, assessed using optical coherence tomography (OCT).
Time frame: Baseline to up to 18 months
Change in Retinal Thickness
Change in retinal thickness from baseline during follow-up, assessed using optical coherence tomography (OCT).
Time frame: Baseline to up to 18 months
Change in Superficial Retinal Vessel Density
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 (%).
Time frame: Baseline to 18 months
Change in Deep Retinal Vessel Density
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 (%).
Time frame: Baseline to 18 months
Change in Foveal Avascular Zone Area
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).
Time frame: Baseline to 18 months
Change in Choriocapillaris Flow Deficit Percentage
Change in choriocapillaris flow deficit percentage from baseline to follow-up, assessed using optical coherence tomography angiography (OCT-A) and expressed as a percentage (%).
Time frame: Baseline to 18 months
Change in Visual Acuity
Change in visual acuity from baseline during follow-up
Time frame: Baseline to up to 18 months
Change in Intraocular Pressure
Change in intraocular pressure from baseline during follow-up, measured in mmHg during routine ophthalmologic examination.
Time frame: Baseline to up to 18 months
Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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