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Study on Ranibizumab Injections and Laser Treatment for Macular Edema in Central Retinal Vein Occlusion Patients

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the treatment of macular edema caused by central retinal vein occlusion. Macular edema is a condition where fluid builds up in the macula, a part of the eye responsible for sharp vision, leading to vision problems. Central retinal vein occlusion occurs when the main vein in the retina becomes blocked, affecting blood flow and causing swelling. The treatment being studied involves the use of Ranibizumab, a medication that is injected into the eye to help reduce the swelling and improve vision. Ranibizumab is an anti-VEGF drug, which means it works by blocking a protein that can cause abnormal blood vessel growth and leakage in the eye.

The purpose of this study is to determine if the regular injections of Ranibizumab can be reduced or even stopped when combined with an early procedure called targeted peripheral laser photocoagulation. This procedure uses a laser to treat specific areas of the retina to help control the condition. Participants in the study will receive Ranibizumab injections, and some will also undergo the laser treatment. The study will monitor how long the injections are needed and whether the additional laser treatment can help reduce the need for them.

Throughout the study, participants will have regular check-ups to assess their vision and the thickness of the macula using a method called OCT (optical coherence tomography), which is a type of imaging test that provides detailed pictures of the retina. The study aims to find out if the combination of treatments can lead to a successful outcome, defined as a period of at least six months without needing further injections. The study will continue until 2026, allowing researchers to gather long-term data on the effectiveness of the treatment approach.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying the diagnosis of macular edema due to central retinal vein occlusion and ensuring foveal thickness is greater than 250 micrometers, as measured by OCT (a type of eye scan).

    Eligibility criteria also require that the patient is at least 18 years old, has a BCVA (best corrected visual acuity) score between 24 and 78 letters in the study eye, and has a history of CRVO (central retinal vein occlusion) no longer than 6 months.

  2. Step 2

    Consent and preparation

    The patient provides written informed consent to participate in the trial. This step ensures understanding and agreement to the trial's procedures and requirements.

    The patient must demonstrate the ability and willingness to attend all scheduled visits and assessments throughout the trial.

  3. Step 3

    Initial treatment phase

    The patient receives three initial monthly injections of ranibizumab, administered via intravitreal use (injection into the eye).

    These injections aim to reduce macular edema and improve visual acuity.

  4. Step 4

    Evaluation and monitoring

    Following the initial treatment phase, the patient's condition is regularly evaluated. This includes measuring the central subfield thickness (CST) using OCT and assessing visual acuity using BCVA letter scores.

    The number of additional ranibizumab injections required is determined based on specific re-treatment criteria.

  5. Step 5

    Optional laser treatment

    Some patients may receive early targeted peripheral laser photocoagulation. This procedure aims to potentially reduce the need for further ranibizumab injections.

    The decision to apply laser treatment is based on the presence of capillary non-perfusion in the peripheral retina, larger than 5 disc areas, as documented in ultra wide-field fluorescein angiography.

  6. Step 6

    Treatment success evaluation

    The primary goal is to achieve treatment success, defined as a treatment-free period of at least 6 months after the last criteria-based intravitreal injection.

    The time to treatment success is monitored, and objective criteria for further treatment are applied as needed.

  7. Step 7

    Ongoing observation

    The patient continues to be observed for up to 29 months after randomization to monitor for any late recurrence of macular edema.

    Regular assessments ensure that any changes in condition are promptly addressed.

Who can join the trial?

8 criteria

  • The patient must have a diagnosis of macular edema due to central retinal vein occlusion. This means there is swelling in the part of the eye called the macula, caused by a blockage in a vein in the retina.
  • The thickness of the macula must be greater than 250 micrometers, as measured by a special eye scan called OCT (Optical Coherence Tomography).
  • The patient must be 18 years of age or older.
  • The patient must provide written informed consent, which means they agree to participate in the study after being fully informed about it.
  • The patient's vision in the study eye must be between 24 letters (20/320) and 78 letters (20/25) on a special eye chart called the ETDRS chart.
  • The patient must have a history of CRVO (Central Retinal Vein Occlusion) for no longer than 6 months.
  • There must be an area in the peripheral retina where blood flow is reduced, larger than 5 disc areas, as shown in a special eye test called ultra wide-field fluorescein angiography.
  • The patient must be able and willing to attend all scheduled visits and assessments required by the study.

Who cannot join the trial?

3 criteria

  • Patients who do not have macular edema caused by central retinal vein occlusion. Macular edema is a condition where fluid builds up in the part of the eye called the macula, leading to swelling. Central retinal vein occlusion is a blockage in the main vein of the retina, the light-sensitive layer at the back of the eye.
  • Patients who are not within the specified age range for the study. The study is open to certain age groups, and those outside these groups cannot participate.
  • Patients who are part of a vulnerable population. This means people who might need special protection or care, such as children, pregnant women, or those with certain disabilities, are not included.
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Investigated drugs

  • Ranibizumab

    is a medication used in this trial to treat macular edema, which is a condition where fluid builds up in the macula, the central part of the retina, leading to vision problems. Ranibizumab works by blocking a protein that causes abnormal blood vessels to grow and leak fluid, helping to reduce swelling and improve vision.

  • Targeted Peripheral Laser Photocoagulation

    is a therapy used alongside Ranibizumab in this trial. It involves using a laser to treat specific areas of the retina. The goal is to reduce the need for frequent Ranibizumab injections by stabilizing the retina and preventing further fluid leakage, potentially improving the long-term outcomes for patients with macular edema due to central retinal vein occlusion.

What is already known about the treatment

Ranibizumab – Ranibizumab is administered as an injection directly into the eye. It is currently used in medicine to treat various eye conditions, including macular edema due to central retinal vein occlusion. The medication works by inhibiting a protein called vascular endothelial growth factor (VEGF), which is responsible for the growth of abnormal blood vessels in the eye that can lead to vision problems. Ranibizumab is classified as an anti-VEGF agent and is widely recognized in medical literature for its effectiveness in improving vision in patients with certain retinal conditions.

Investigated diseases

Macular Edema Due to Central Retinal Vein Occlusion – This condition occurs when the central retinal vein, responsible for draining blood from the retina, becomes blocked. The blockage leads to increased pressure in the retinal blood vessels, causing fluid to leak into the macula, the central part of the retina responsible for sharp vision. As fluid accumulates, the macula swells, resulting in blurred or distorted vision. Over time, if untreated, the swelling can lead to more severe vision impairment. The progression of the disease can vary, with some individuals experiencing gradual worsening of symptoms. Regular monitoring is essential to manage the condition effectively.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-507816-11-00Protocol codeCoRaLa IIEstimated enrolment110 patientsSponsorJustus-Liebig-Universitaet Giessen

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