Robotic RVO Trial: Robot-assisted Retinal Vein Cannulation in Patients With Retinal Vein Occlusions

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.