We investigated the relationship between the circumferential extent of peripheral anterior synechiae (PAS) and the severity of visual field defects in primary angle-closure glaucoma (PACG). Correlations between visual field defects and the extent of PAS were analyzed in 73 eyes; 28 with and 45 without acute attacks. Spearman's correlation coefficient between the severity of visual field defects and the extent of PAS was 0.348 (P = 0.003) in all subjects (n = 73), 0.377 (P = 0.012) in the PACG eyes without acute attacks (n = 45), and 0.338 (P = 0.079) in the eyes with acute attacks (n = 28). Our results showed a statistically significant correlation between the extent of PAS and the severity of visual field damage in PACG overall, and especially in PACG patients without a history of acute attacks.