Purpose To investigate the levels of matrix metalloproteinases (MMPs) in aqueous humour of patients with retinal vein occlusion (RVO) and the relationship between intraocular MMP levels and retinal lesion and visual prognosis.

Materials and methods 52 RVO patients, including 23 with central retinal vein occlusion (CRVO) and 29 with branch retinal vein occlusion (BRVO) and 20 participants with senile cataract were enrolled in this study. Retinal lesions were examined by fundus colour photography, fluorescein fundus angiography and optical coherence tomographic angiography. Sixty microliters of aqueous humour were collected during intravitreal anti-Vascular Endothelial Growth Factor (VEGF) injection or cataract surgery. The aqueous levels of MMP-1, MMP-2, MMP-7, MMP-9 and MMP-10 were measured using the Luminex xMAP multiplex assay. The relationship between MMP levels and clinical presentations was analysed by Pearson correlation test.

Results The aqueous humour levels of MMP-1, MMP-2, MMP-7 and MMP-9, but not MMP10 in RVO patients were significantly higher than those in people with cataract after adjusting for age. Further analysis of RVO subgroups showed that the aqueous humour level of MMP2 in CRVO was significantly higher than that in BRVO. The aqueous humour levels of MMP-1 and MMP-2 were positively correlated with superficial capillary plexus vessel density (SVD), whereas the aqueous humour levels of MMP-1 and MMP-7 were negatively correlated with visual improvement following treatment. No correlation between aqueous humour levels of MMP and disease duration and central retinal thickness was observed.

Conclusions RVO eyes had significantly higher intraocular levels of MMP-1, MMP-2, MMP-7 and MMP-9 than cataract eyes and the level of MMP2 appears to be related to the area of occlusion. Intraocular levels of MMP may positively affect SVD and negatively impact visual function in RVO.