AIM: To evaluate the effects of 23G vs 20G pars plana vitrectomy(PPV)combined with internal limiting membrane peeling, phacoemulsification and intraocular lens implantation for macular epiretinal membrane with cataract.

METHODS: Totally 45 eyes of 45 patients with macular epiretinal membrane and cataract were enrolled in this retrospective non-randomized controlled clinical study. All eyes were treated with PPV combined with internal limiting membrane peeling, phacoemulsification and intraocular lens implantation. There were 20 eyes in 23G PPV group, and 25 eyes in 20G PPV group. The best corrected visual acuity(BCVA), intraocular pressure(IOP), counting of corneal endothelial cells(CEC)and central retinal thickness(CRT)were examined before surgery. BCVA results were converted to the logarithm of the minimum angle of resolution(LogMAR)visual acuity. All operations were performed by the same doctor. Operation time for vitrectomy and membrane peeling, average ultrasound energy(AVE)and effective phacoemulsification time(EPT)were recorded. BCVA and CRT were observed postoperatively at 30d and 90d, counting of CEC was observed postoperatively at 90d. IOP was observed postoperatively at 1d and 7d.

RESULTS: The mean operation time for vitrectomy were 12.57±1.35min in 23G group and 17.30±1.19min in 20G group. The difference was statistically significant(t=-12.488, P<0.01). There were no statistical significances in operation time for membrane peeling, AVE and EPT between 23G and 20G groups(t=-0.68,-1.186,-0.737,P=0.500, 0.242,0.465). On 1d after surgery, IOP in 23G group was lower than that in 20G group, the difference was statistically significant(t=-2.345, P=0.024). The BCVA and CRT of the two groups both improved after operations. There were no statistically significant differences between two groups in terms of IOP, BCVA, and CRT(F=0.465, 1.895, 0.689; P=0.499, 0.176, 0.411). IOP, BCVA and CRT were significant statistical different in different time-point within each group(F=291.245, 103.06, 665.402, P<0.01). Different surgical methods of 23G and 20G had interactive effects on IOP with different time points(F=13.245, P<0.01), but different surgeries had no interactive effects on BCVA and CRT with different time points(F=1.212, 2.293; P=0.283, 0.129). The counting CEC in 23G group was more than that in 20G group postoperatively at 90d, the difference was statistically significant(t=2.049, P=0.048).

CONCLUSION: The 23G PPV combined with internal limiting membrane peeling, phacoemulsification, intraocular lens implantation for macular epiretinal membrane with cataract is effective. Compared with 20G PPV, 23G PPV has advantages in operation time for vitrectomy and counting CEC. But lower IOP is likely in 23G PPV on 1d after surgery