Objective To evaluate the effects of micro-monovision design combined with extended depth of focus (EDOF) intraocular lens (IOL) implantation on visual function in patients undergoing phacoemulsification for cataract. Methods A total of 90 patients who underwent phacoemulsification and IOL implantation in the department of Ophthalmology, Affiliated Wuxi People’s Hospital of Nanjing Medical University Hospital between June 2024 and August 2025 were consecutively enrolled. Patients were randomly assigned via a random number table to an observation group (n=45) and a control group (n=45). The observation group underwent micro-monovision design combined with EDOF IOL implantation, while the control group underwent trifocal IOL implantation. Uncorrected visual acuity, visual quality, defocus curves, contrast sensitivity, and spectacle independence were observed and compared between the two groups at 6 months postoperatively. Adverse visual phenomena during follow-up were also recorded. Results (1) No significant differences were found in baseline clinical characteristics between the two groups (all P>0.05). (2) No significant difference was observed in preoperative VF-14 scores between the two groups (P>0.05). Postoperative VF-14 scores in the observation group were higher than those in the control group, and postoperative VF-14 scores in both groups were higher than their respective preoperative scores (all P<0.05). (3) The defocus curve of the observation group demonstrated excellent uncorrected distance visual acuity (UDVA) within the diopter range of +0.50 D to -0.50 D, acceptable uncorrected intermediate visual acuity (UIVA) within -1.00 D to -2.00 D, and good uncorrected near visual acuity (UNVA) within -2.50 D to -3.50 D. In the control group, good UDVA was maintained from +0.50 D to -0.50 D, good UNVA was maintained from -2.50 D to -4.00 D, and good UIVA was maintained from -0.50 D to -2.50 D. Comparison revealed that visual acuity within the +0.50 D to -0.50 D range was higher in the observation group than in the control group. (4) Contrast sensitivity (CS) under various photopic, mesopic conditions and spatial frequencies was significantly higher in the observation group compared to the control group (all P<0.05). (5) The postoperative spectacle independence rate was higher in the observation group, while the incidence of adverse visual phenomena was lower, with both differences being statistically significant (all P<0.05). Conclusion The micro-monovision design can improve uncorrected intermediate and near visual acuity and provide more stable visual performance in patients undergoing phacoemulsification combined with EDOF IOL implantation. This approach offers superior visual quality, better contrast sensitivity function, a higher rate of postoperative spectacle independence, and a lower risk of adverse visual phenomena, making it an optimized surgical strategy for cataract patients.