AIM: To investigate the effect of simulated dynamic intraocular pressure (SDIOP) during uncomplicated phacoemulsification on postoperative macular and peripapillary retinal nerve fiber layer (RNFL) thickness. METHODS: Macular and RNFL thicknesses in one eye of patients (n=30) undergoing uncomplicated phacoemulsification were measured by optical coherence tomography preoperatively and 1 week postoperatively. The best-corrected visual acuity, SDIOP, irrigation time (IT), effective phacoemulsification time, entire surgical duration, blood pressure, and heart rate were recorded. RESULTS: The mean SDIOP and IT was (74.9 ± 27.4)cmH2O and (178.4 ± 21.6) seconds respectively. We divided our patients into two groups based upon IT with greater than 90cmH2O (P_>90IT). In Group A (n=14), the P_>90IT was greater than the mean P_>90IT, and in Group B (n=16), the P_>90IT was less than the mean P_>90IT. For all patients there was a significant increase in macular thickness one week after cataract surgery (P=0.001). While the RNFL thickness tended to increase, the change was not significant. The postoperative macular thickness of Group A, (277.8 ± 13.7)μm, was significantly thicker than that of Group B, (267.9 ± 15.0)μm (P=0.004). The postoperative peripapillary RNFL thickness of Group A, (96.8 ± 10.8) μm, was not significantly different from Group B. For Group A, the change in macular thickness was positively correlated with P_>90IT (R2=0.524, P=0.02). There was no statistical difference in postoperative visual acuity between Groups A and B. CONCLUSION: After uncomplicated phacoemulsification, increased macular thickness is associated with the IT under high SDIOP. The effect of high SDIOP is limited to the sub-clinical level.