Bevacizumab, an anti-VEGF (vascular endothelial growth factor) agent used in the treatment of diabetic retinopathy and macular edema associated with retinal vein occlusion, is commonly administered in ophthalmology clinics through intravitreal injection. The systemic use of bevacizumab has been associated with serious conditions such as thromboembolism and bleeding. Although intravitreal bevacizumab is administered in smaller amounts and has limited systemic circulation, it requires repeated injections over a long period. These long-term intravitreal anti-VEGF therapies may lead to adverse outcomes, particularly thromboembolism, due to systemic inhibition of VEGF. However, limited information is available regarding the potential effects of this treatment on the systemic and cardiovascular systems. To evaluate this risk, the study aims to assess changes in the activities of paraoxonase 1 (PON1), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), which are closely associated with lipid metabolism, coronary artery disease, and atherosclerosis. These enzymes are known biomarkers of cardiovascular health and play significant roles in protection against oxidative stress and inflammation. For this purpose, a case-control study is planned. Serum BChE and PON1 activities, as well as triglyceride (TG)/high-density lipoprotein (HDL) and TG/glucose ratios, will be determined in patients receiving repeated intravitreal bevacizumab injections and in control groups, and cardiovascular disease risk will be assessed. This study may help us better understand the safety profile of this treatment by revealing the effects of bevacizumab on serum enzyme activities and cardiovascular risk factors. These findings could contribute to optimizing treatment strategies in clinical practice.
Who can participate
Age range
50 Years – 80 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Age ≥ 55 years.
* Ability to provide written informed consent.
* Patient group: Diagnosis of macular edema secondary to diabetic retinopathy, retinal vein occlusion, or age-related macular degeneration, and having received repeated intravitreal bevacizumab injections (≥2 doses).
* Control group: Healthy volunteers with no ocular pathology other than cataracts and not receiving intravitreal anti-VEGF treatment.
Exclusion Criteria:
* Chronic inflammatory disease.
* Chronic infectious disease.
* History of cardiovascular disease (e.g., coronary artery disease, heart failure, arrhythmia requiring treatment).
* History of cerebrovascular disease (e.g., stroke, transient ischemic attack).
* Any additional ocular pathology that may affect the study outcomes (other than the index retinal condition in the patient group and cataract in the control group), such as:
glaucoma
uveitis
retinal dystrophies
significant media opacity preventing adequate ocular evaluation
\- Use of systemic medications or conditions known to affect cholinesterase activity markedly
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1This trial is measuring changes in a blood enzyme called butyrylcholinesterase after intravitreal bevacizumab injections — can you explain what that enzyme has to do with my heart health, and why that connection matters for someone with my condition?
2Since this study is listed as 'Phase NA,' it sounds more like an observational or measurement study than one testing a new treatment — does that mean I'd still be receiving standard bevacizumab injections, and what, if anything, would be different about my care if I participated?
3The trial involves patients with diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration — given which of these conditions I have, do you think my situation fits closely enough with what this study is actually looking at?
4If the study is tracking cardiovascular risk markers in my blood after injections, does that mean there's a known concern about bevacizumab affecting the heart or blood vessels, and is that something I should already be thinking about with my current treatment?
5Would joining this trial require extra blood draws, additional visits, or any other demands on my time beyond what my regular eye care already involves, and how might that fit with managing my other health conditions?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Serum butyrylcholinesterase (BChE) activity
Timeframe: Within 7 days after the most recent intravitreal bevacizumab injection