PurposeTo compare 1.8mm micro-incision and 2.75mm standard incision in coaxial cataract surgery combined with 23-Gauge (23G) vitrectomy with respect to intraoperative and postoperative complications and outcomes. MethodsIn this prospective study 30 eyes of 30 patients planned for combined phacoemulsification and 23G vitrectomy were enrolled, and randomized to undergo either Standard 2.75mm Incision Cataract Surgery (SICS, 15 eyes) or Coaxial 1.8mm Micro-Incision Cataract Surgery (C-MICS, 15 eyes) followed by vitrectomy. Inclusion criteria were cataract and macular disorders including macular hole, epiretinal membrane and vitreomacular traction. Data were collected at preoperative evaluation and 1 and 12months or more after surgery. ResultsIncision leakage occurred in two eyes (7%: one per group), retinal break in nine (30%: four in C-MICS, five in SICS). Fibrin in anterior chamber (AC) occurred day 1 in three eyes (10%: two C- and one SICS). Posterior capsule opacification developed in 22 eyes (78%: 13 MICS, nine SICS, p=0.1). A myopic shift of -0.630.7 was noted (-0.59 +/- 0.8 MICS, -0.68 +/- 0.6 SICS, p=0.74). Surgically induced astigmatism (SIA) was significantly smaller in C-MICS group (KP, -0.019 +/- 0.095 versus -0.141 +/- 0.219, p=0.0038) at 1month but not at final follow-up (KP, 0.0005 +/- 0.16 in C-MICS versus -0.057 +/- 0.12, p=0.3 ConclusionsBoth techniques were equally safe with respect to intraoperative and postoperative findings. Coaxial micro-incision cataract surgery (C-MICS) was associated with less surgically-induced astigmatism (SIA) 1month after surgery but differences were not statistically significant at final follow-up indicating a faster refractive recovery with C-MICS than with SICS.