CTSO and age-related macular degeneration: MVMR analysis indicated a causal relationship between cathepsin G (IVW: p = 0.025; OR = 1.124; 95% CI = 1.014–1.245), cathepsin O (IVW: p = 0.043, OR = 1.158, 95% CI = 1.004–1.336), and exudative AMD after coordinating for other types of cathepsin.