AIM: To discuss the advantages and disadvantages of combined surgery, which consists of posterior segment diseases and anterior segment diseases(cataract, glaucoma, keratonosus), and analyze the hazards that may affect surgery.

METHODS: Group A: proliferative diabetic retinopathy(PDR), group B: complicated retinal detachment(RD). For comparison, group A was divided to group A₁: vitrectomy; group A₂: vitrectomy + cataract extraction; group A₃: vitrectomy + cataract extraction + intraocular lens implantation. Group B was divided to group B₁: vitrectomy; group B₂: vitrectomy + cataract extraction; group B₃: vitrectomy + cataract extraction+ intraocular lens implantation.

RESULTS: Surgery complications were the main outcome measures: neovascularity secondary glaucoma in group A and surgery recurrence or proliferative vitroretinopathy in group B. The incidence of complication: group A₃>A₂>A₁, A₃ was significantly higher than A₂ and A₁, and it was statistically significant, A₂>A₁, but it was not statistically significant. The results of group B were the same as group A.

CONCLUSION: Combined surgery will not be chosen if it is possible, and intraocular lens should not be implanted at once if the operation was influenced.