Objective  To explore the feasibility of 5.5?mm long clear corneal incisions,through which PMMA (unfoldable) IOLs could be implanted.Methods  60 rabbit eyes were divided into three groups.5.5?mm long superior sutureless clear corneal paracentesis was performed on eyes of group A and tunnel incision with a width of 2 mm was done on eyes of group B.In group C (as the control group),all eyes were treated with 3.2?mm clear corneal paracentesis.Results  Two weeks after the surgery, incisions of all eyes in three groups were favorably self  sealing.And there is significant difference between preoperative and postoperative vertical astigmatism value of group A,so is postoperative astigmatism value of group A and that of group C.There is no significant difference between preoperative and postoperative vertical astigmatism value of group B,neither is in group C,and the same is true between postoperative value of group B and that of group C.Also,the inflammatory reactions of anterior chamber were more severe in group A than in group B observed by the slit  lamp.Conclusions  All the three methods of clear corneal incision are easy to use and the incision is reliably self  sealing.The incisions in group B have less influence in curvature of the corneal than that in group A.The experiment suggests that the 5.5?mm clear corneal incision is a possible and ideal approach,through which unfoldable IOLs could be implanted.