Abstract: To explore the change law of the retinal nerve fiber layer （RNFL） thickness in acute primary angleclosure glaucoma （APACG）. Methods26 subjects of APACG with the first acute attack(＜6?hours) and 30 normal controls were included in this study. The RNFL thickness was accessed by optical coherence tomography （OCT）on the 1st day when the cornea became clear and at 1 week,1 month, 3 months，and 6 months after intraocular pressure( IOP) was controlled（5 times ）. RNFL thickness was compared between attacked eyes and normal control eyes. ResultsRNFL thickness on the 1st day of corneal transparency（122.14±21.37）μm was thicker than that of normal controls（P<0.01）.At 1 week after IOP was controlled, RNFL thickness （110.25±17.43）μm was thicker than that of normal controls （P<0.05）. At 1 month after IOP was controlled, RNFL thickness （103.34±15.19）μm was a little thicker than that of normal controls （P>0.05）, there was no significant difference. At 3 months （102.56±14.11）μm and 6 months （101.22±15.54）μm after IOP was controlled, RNFL thickness was a little thinner than that of normal control (P>0.05) , and there were no significant differences. ConclusionIn the early period, acute rising of IOP caused edema of the retina, and RNFL became thicker. After IOP decreased to a normal range, RNFL became thinner. At 3 and 6 months after IOP was controlled, the RNFL thickness tended to be stable.