Background/aims Correlations among functional–morphological parameters, the aqueous flare value (an indicator of inflammation) and aqueous humour levels of cytokines/inflammatory factors were investigated in patients with branch retinal vein occlusion (BRVO) and macular oedema who received intravitreal ranibizumab injection (IRI) and were followed for 6 months.

Methods Aqueous humour levels of 11 cytokines or growth inflammatory/factors were measured in 45 patients with BRVO and macular oedema who received IRI. Patients with recurrent macular oedema were given further IRI as needed. Aqueous humour levels of vascular endothelial growth factor (VEGF), soluble VEGF receptor (sVEGFR) and other cytokines/inflammatory factors were measured by the suspension array method. Aqueous flare values were measured with a laser flare metre and macular oedema was examined by optical coherence tomography.

Results There were significant correlations between the aqueous flare and the aqueous levels of sVEGFR-1, placental growth factor, monocyte chemoattractant protein 1, soluble intercellular adhesion molecule-1, interleukin (IL)-6 and IL-8. There were also significant correlations between the change of the aqueous flare and improvement of central macular thickness after 1 month, after 6 months and at the 1st recurrence. Furthermore, a significant correlation was noted between the change of the aqueous flare and improvement of best-corrected visual acuity at 6 months after IRI, but not at 1 month or at the 1st recurrence.

Conclusions These findings suggest that the aqueous flare is associated with inflammatory factors/cytokines, and that the change of the aqueous flare value may influence the long-term prognosis in patients with BRVO receiving IRI therapy for macular oedema.