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Retinal Blood Flow in Response to an Intravitreal Injection of Ranibizumab for Central Retinal Vein Occlusion (CRVO)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01303276
Recruitment Status : Unknown
Verified February 2011 by University of Toronto.
Recruitment status was:  Not yet recruiting
First Posted : February 24, 2011
Last Update Posted : February 24, 2011
Information provided by:
University of Toronto

Brief Summary:
Ranibizumab (Lucentis, Genentech) is an off-label drug used for the clinical treatment of central retinal vein occlusion, which is one of the most common retinal vascular disorders. Despite its clinical effectiveness, concerns remain regarding the systemic effects of the drug and previous studies have noted retinal arteriolar vasoconstriction following a ranibizumab injection. We aim to provide a physiological basis to these observations by assessing retinal blood flow before and after the ranibizumab injections. Specifically, we will assess the blood flow parameters (i.e. retinal vessel diameter, velocity & flow) immediately before the first injection and post-injection over a follow-up continued treatment period.

Condition or disease
Central Retinal Vein Occlusion

Detailed Description:

Ranibizumab is an antibody fragment designed to inhibit the activity of Vascular Endothelial Growth Factor (VEGF), which is responsible for the neovascularization and retinal edema responsible for interference of normal vision in central retinal vein occlusion. However, VEGF has a role in the vasculature as a vasodilator where it alters the expression of tight junction proteins and upregulates the release of the vasodilator nitric oxide. Consequently, intravitreal ranibizumab injections could result in systemic inhibition of VEGF, leading to long-term retinal arteriolar vasoconstriction and potentially adverse cerebrovascular and myocardial accidents. Therefore, evaluating retinal blood flow would provide a physiological foundation to this concern and provide physicians with valuable information regarding the risks of continued ranibizumab therapy.

Given the role of VEGF as a vasodilator in the vasculature where it works to alter the expression of tight junction proteins and the production of vasoactive substances especially nitric oxide, inhibiting this molecule with ranibizumab could result in vasoconstriction in these vessels. We hypothesize that vasoconstriction and decreased retinal blood flow will be observed after an intravitreal injection of ranibizumab for treatment of central retinal vein occlusion.

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Study Type : Observational
Estimated Enrollment : 30 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Retinal Blood Flow in Response to an Intravitreal Injection of Ranibizumab for Central Retinal Vein Occlusion
Study Start Date : June 2011

Resource links provided by the National Library of Medicine

Drug Information available for: Ranibizumab

Anti-VEGF group
Patients who are clinically indicated for the intravitreal injection of ranibizumab
Age-matched controls
Group of healthy participants who will be age and gender matched

Primary Outcome Measures :
  1. Quantitative change in retinal blood flow [ Time Frame: Baseline, 7, 30 days ]
    Retinal blood flow will be measured using Canon Laser Blood Flowmeter

Secondary Outcome Measures :
  1. Best Corrected Visual Acuity (LogMAR, EDTRS) [ Time Frame: Baseline, 7, 30 days ]
    Best Corrected Visual Acuity will be examined using 96% and 10 % contrast EDTRS letter charts

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   50 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Patients with central retinal vein occlusion will be recruited from the Retina Clinics of Toronto Western Hospital

Inclusion Criteria:

  • Age > 50 years
  • central retinal vein occlusion scheduled for first intravitreal injection of ranibizumab as part of their clinical care

Exclusion Criteria:

  • previous history of intravitreal therapy,
  • history of thromboembolic events,
  • glaucoma or an intraocular pressure >21 mmHg
  • diabetes mellitus or altered blood viscosity syndromes
  • blood donation in the previous 2 weeks
  • refractive error of +/- 6.00 DS and/or 2.00 DC

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01303276

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Contact: Edmund Tsui, BSc (416)603-5694 ext 5694
Contact: Tien Wong, BSc (416)603-5694 ext 5694

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Canada, Ontario
Toronto Western Hospital
Toronto, Ontario, Canada, M5T 2S8
Contact: Edmund Tsui, BSc    (416)603-5694 ext 5694   
Contact: Tien Wong, BSc    (416)603-5694 ext 5694   
Principal Investigator: Christopher Hudson, PhD         
Sub-Investigator: Michael Brent, MD         
Sub-Investigator: Wai-Ching Lam, MD         
Sub-Investigator: Robert G Devenyi, MD         
Sub-Investigator: Mark Mandelcorn, MD         
Sponsors and Collaborators
University of Toronto
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Principal Investigator: Christopher Hudson, PhD University of Toronto
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Responsible Party: Christopher Hudson, University of Toronto Identifier: NCT01303276    
Other Study ID Numbers: CRVO-blood flow study
First Posted: February 24, 2011    Key Record Dates
Last Update Posted: February 24, 2011
Last Verified: February 2011
Keywords provided by University of Toronto:
retinal vein occlusion
blood flow
Additional relevant MeSH terms:
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Retinal Vein Occlusion
Retinal Diseases
Eye Diseases
Venous Thrombosis
Embolism and Thrombosis
Vascular Diseases
Cardiovascular Diseases