Abstract: Objective To explore the causal relationship between Rheumatoid Arthritis (RA) and ocular diseases using Mendelian randomization (MR). Methods The single nucleotide polymorphisms (SNPs) of RA and ocular diseases were extracted from the Genome-Wide Association Study (GWAS) available in the Integrative Epidemiology Unit (IEU) database. The study used inverse variance-weighted (IVW), MR-Egger regression, and other analytical methods to analyze the causal relationship between RA and ocular diseases by MR. The IVW approach was the principal analysis method. Results The IVW MR analysis revealed a causal association between RA and an increased risk of cataract (OR=1.043, 95% CI: 1.019-1.069, P<0.01), but not statistically significant with increased risk of glaucoma and age-related macular degeneration (AMD) (both P>0.05). The reverse two sample MR analysis indicated no current evidence of a causal association between cataract, glaucoma, and increased risk of RA. Sensitivity analysis showed that the results were relatively robust. By multivariate MR analysis, RA was associated with an increased risk of cataract (OR=1.036, 95% CI: 1.008-1.064, P=0.010). There was no evidence of a causal association between RA and glaucoma, AMD, or cataract, glaucoma, and RA (all P>0.05). Conclusions RA increases the risk of developing cataracts, but does not increase the risk of developing glaucoma or AMD.

Key words: Mendelian randomization, Rheumatoid arthritis, Ocular diseases, Causal inference