Conservative treatments may not work for central retinal artery occlusion (CRAO) but systemic fibrinolysis with clot-busting agents given early on may help stave off blindness.

“There’s no convincing evidence that any conservative treatment modality [eg, ocular massage, hemodilution, or anterior chamber paracentesis] is effective,” researchers said. “They may even be harmful as shown in this meta-analysis.”

Dr.  Matthew Schrag and colleagues from the Yale University in Connecticut, US reviewed studies reporting visual acuity outcomes after CRAO, an eye condition resulting from thrombosis and embolism which could lead to retinal ischaemia and blindness, and looked at a time window when fibrinolytic therapy is effective. Rate of visual recovery, defined as improvement of visual acuity from 20/200 or worse at presentation to 20/100 or better, was calculated after treatment with fibrinolytics (intravenous tissue plasminogen activator, streptokinase, or urokinase), conservative therapies, or no treatment. [JAMA Neurol 2015; doi:10.1001/jamaneurol.2015.1578]

Recovery rates were significantly higher with fibrinolytics versus conservative treatment or no treatment (31.3 vs 7.4 and 17.7 percent; p<0.001). Conservative treatment caused more harm compared with no treatment, suggesting that standard treatments may be “futile.”

Time of fibrinolysis was, however, critical – a 50 percent recovery rate was observed if clot-busting agents were given within the first 4.5 hours of symptom onset. “This translates to a five-fold increased likelihood of recovery versus no treatment [odds ratio, 4.7; p<0.001],” said Schrag. Absolute risk reduction was 32.3 percent and the number needed to treat was 4. By contrast, fibrinolysis beyond 4.5 hours of symptom onset yielded no statistical benefit. The take home message: fibrinolysis should start earlier.

Considering that no proven therapy for CRAO currently exists, more studies of early systemic fibrinolysis are warranted, said the researchers. Limitations of the analysis include variability in specific treatment procedures between and within studies and the retrospective and non-randomized nature of the data.