Overview

Retinal vein occlusions (RVOs) are the second leading cause of permanent vision loss in the UK. Current treatments, like anti-VEGF injections or steroids, address complications such as macular fluid but do not target the underlying issue-a clot in the retinal vein. Direct injection of clot-dissolving agents, such as tissue plasminogen activator (tPA), is challenging due to the small size of retinal veins. This surgical trial aims to inject tPA directly into the blocked retinal vein to dissolve the clot and restore blood flow.

This surgical trial aims to inject tPA directly into the blocked retinal vein to dissolve the clot and restore blood flow. Robotic assistance will stabilise the injection cannula, ensuring precise and slow infusion of tPA. This study will compare outcomes in patients receiving standard care for RVOs (the control group) with those receiving standard treatment plus the robot-assisted tPA injection (the study group). The robotic system has been clinically validated and has received CE marking for vitreoretinal interventions, including tPA injection beneath the retina.

tPA has been safely used in the eye with no reported safety concerns. It is licensed for intravenous use for thromboembolic events that lead to ischemia. RVO (an ischemic stroke of the eye) is a specific example. Instead of systemic administration through the peripheral vein, we will be directly delivering tPA into the occluded retinal vein, effectively treating the localised ischemia, within licensed intent.

40 eligible participants diagnosed with RVO will be recruited from the NHS clinic. Participants will be randomly allocated to the control group or the study group and will be monitored for 12 months. The study focuses on safety as the primary outcome and efficacy in terms of retinal structure and function as secondary outcomes. If successful, this trial could lead to a new intervention for RVO-related vision loss.

Eligibility

Inclusion Criteria:

• Participant is wiling and able to give informed consent for participation in the trial
• Male or Female aged 18 years or above
• Recently diagnosed with central RVO (\<4 weeks)
• In the Investigator's opinion, the patient is able and willing to comply with all trial requirements and is deemed fit for treatment.
• ETDRS BCVA letter score of 70 or less or Snellen equivalent (\< 6/12) in the study eye at Screening Visit 1

Exclusion Criteria:

• Participants with comorbidities contraindicating vitreoretinal surgery (e.g. excessive tremor) as determined by the investigator.
• Participants with ocular comorbidities contraindicating the use of steroid implants (e.g. glaucoma) or anti-VEGFs as determined by the investigator.
• Participants who are participating in another research trial involving an investigational product or surgical intervention.
• Participants with known allergy to Fluorescein
• Participants with contraindications for the use of tPA (Alteplase, Boehringer Ingelheim, Germany) or currently receiving or starting medications that have a known interaction with tPA, as identified in the SmPC, which may alter its efficacy or safety profile of tPA.