Subthreshold laser therapy for macular oedema from branch retinal vein occlusion: focused review

Retinal vein occlusion is the second-leading cause of vision loss by retinal vascular disease. Subthreshold micropulse laser therapy (SLT) is safer than conventional laser photocoagulation (CLP), yet existing reviews of its use for branch retinal vein occlusion (BRVO) are limited in scope. A literature search of PubMed, Google Scholar, Embase, Cochrane Library and ClinicalTrials.gov databases was conducted in August 2019 without restriction on language or publication date. Outcomes included changes in macular oedema (ME) and visual acuity (VA), and rates of complications or retreatments. Fourteen studies involving 315-405 eyes diagnosed with BRVO were evaluated. Treatment with SLT is associated with significant and durable reduction of ME and VzA as early as 1 month. SLT performs comparably with conventional photocoagulation and intravitreal injections (IVIs) of ranibizumab. Subthreshold laser therapy is safer and as effective as CLP for the treatment of ME associated with BRVO. SLT may be used in combination with anti-VEGF IVIs to enhance improvement in VA and ME resolution.