Promising Clinical Trial for Retinal Vein Occlusion
The Save Sight Institute (SSI) Macular Research Group (MRG) has currently over 15 clinical trials of new treatments for macular disease being run through the Sydney Eye Hospital. One of these is an exciting new SSI-initiated study treating swelling of the central macula (macular oedema) due to retinal vein occlusions (blood clots).
Near infrared light for the treatment of macular oedema from retinal vein occlusions (NIRVO) is a clinical trial looking at safety and efficacy of a light treatment instead of eye injections which are the usual treatment these days. Eye injections work very well but most patients need to continue them for many years to maintain their vision because they only last for a month or two. A less invasive treatment may have many advantages and better tolerated. Â Near infrared light treatment is thought to work by stimulating cellular metabolism and repair.
Occlusions of the retinal veins can reduce vision of patients because they cause macular oedema (Figure 1B). Retinal vein occlusions typically occur in patients over 50 years of age with cardiovascular risk factors such as hypertension, diabetes, high cholesterol, obesity and smoking.
Figure 1: Clinical images of a retinal vein occlusion.
A Image of the retina showing an inferior branch retinal vein occlusion with retinal hemorrhages
B Cross section through the macula showing macular oedema (red arrows demonstrating fluid)
The MRG recently published results from a pilot study demonstrating that this near infrared light was effective and safe when treating macular oedema due to diabetic retinopathy (1). Twelve 90 second treatment sessions with this light reduced the patients’ macular oedema (Figure 2) and the subsequent requirement for eye injections. The US Diabetic Retinopathy Research Collaboration is currently recruiting for a larger study with near infrared light which may or may not confirm our findings (2).
Figure 2: Pre (A&C) and Post (B&D) near infrared light treatment course for macular oedema due to diabetic retinopathy.
A&B: Retinal images demonstrating thickening/swelling with the red shading. A is before treatment and B is following treatment with near infrared light
C&D: Cross section through the macula with macular oedema (red arrow, C) that resolves after near infrared light treatment (D).
A&B: Retinal images demonstrating thickening/swelling with the red shading. A is before treatment and B is following treatment with near infrared light
C&D: Cross section through the macula with macular oedema (red arrow, C) that resolves after near infrared light treatment (D).
The NIRVO study may provide proof of principle for a definitive placebo controlled clinical trial which would be required before the treatment could be widely adopted. The project, which received support from the Ophthalmic Research Institute of Australia, recently enrolled its third participant. We are very excited to see what we will learn from this new potential treatment.
1. Shen W, Teo KYC, Wood JPM, Vaze A, Chidlow G, Ao J, et al. Preclinical and clinical studies of photobiomodulation therapy for macular oedema. Diabetologia. 2020;63(9):1900-15.
2. ClinicalTrials.gov Identifier: NCT02457975