Macular grid laser photocoagulation for branch retinal vein occlusion

Background Branch retinal vein occlusion (BRVO) is the second most common cause of retinal vascular abnormality after diabetic retinopathy. Persistent macular oedema develops in 60% of eyes with a BRVO. Untreated, only 14% of eyes with chronic macular oedema will have a visual acuity (VA) of 20/40 or better. Macular grid laser photocoagulation is used for chronic non‐ischaemic macular oedema following BRVO and has been the mainstay of treatment for over 20 years. New treatments are available and a systematic review is necessary to ensure that the most up‐to‐date evidence is considered objectively. Objectives To examine the effects of macular grid laser photocoagulation in the treatment of macular oedema following BRVO. Search methods We searched CENTRAL, Ovid MEDLINE, EMBASE, Web of Science Conference Proceedings Citation Index, the metaRegister of Controlled Trials (mRCT), ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform. We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 21 August 2014. Selection criteria We included randomised controlled trials (RCTs) comparing macular grid laser photocoagulation treatment to another treatment, sham treatment or no treatment. Data collection and analysis We used standard methodological procedures expected by Cochrane. Main results We included five studies conducted in Europe and North America. Four separate trials compared grid laser to no treatment, sham treatment, intravitreal bevacizumab and intravitreal triamcinolone. One further trial compared subthreshold to threshold laser. Two of these trials were judged to be at high risk of bias in one or more domains. In one trial of grid laser versus observation, people receiving grid laser were more likely to gain visual acuity (VA) (10 or more ETDRS letters) at 36 months (RR 1.75, 95% confidence interval (CI) 1.08 to 2.84, 78 participants, moderate‐quality evidence). The effect of grid laser on loss of VA (10 or more letters) was uncertain as the results were imprecise (RR 0.68, 95% CI 0.23 to 2.04, 78 participants, moderate‐quality evidence). On average, people receiving grid laser had better improvement in VA (mean difference (MD) 0.11 logMAR, 95% CI 0.05 to 0.17, high‐quality evidence). In a trial of early and delayed grid laser treatment versus sham laser (n = 108, data available for 99 participants), no participant gained or lost VA (15 or more ETDRS letters