Serum miR-26a level is decreased in cataract patients with glaucoma and related to visual quality.

Clinical relevance: microRNAs have been found to be involved in the progression of a variety of ocular diseases.

Background: Cataract and glaucoma often coexist, and combined surgery is a common treatment. The aim of this study is to analyse the correlation between miR-26a and visual quality in cataract patients with glaucoma.

Methods: Seventy patients with cataract and glaucoma and 70 healthy volunteers were enrolled and received phacoemulsification and trabeculectomy. The patients were divided into low and high miR-26a expression groups according to miR-26a mean expression. The objective scattering index, strehl ratio, and modulated transfer function cut-off were analysed by optical quality analysis system II. The changes of miR-26a, objective scattering index, strehl ratio, modulated transfer function cut-off, and the correlation between the indicators were analysed. The downstream genes of miR-26a were analysed by Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes functional enrichment.

Results: There were significant differences between patients and controls in lipid biomarker levels and visual indicators. miR-26a was decreased in the patient group. Strehl ratio and modulated transfer function cut-off in the miR-26a low-expression group were lower than in high-expression group, while mean defect of the visual field and objective scattering index were higher than in high-expression group. The miR-26a expression was negatively correlated with the severity of disease and objective scattering index, and positively correlated with strehl ratio and modulated transfer function cut-off. After surgery, miR-26a, strehl ratio, and modulated transfer function cut-off were increased, and objective scattering index was decreased. The downstream genes of miR-26a were related to several biological processes and signalling pathways.

Conclusion: In cataract patients with glaucoma, miR-26a expression was lower than matched controls and increased following combined cataract removal and trabeculectomy.