AIM: To observe the clinical effect of 2.5 mm-long hooker using improved pre-chop phacoemulsification method with ozil technique and to discuss the clinic characteristics of this improved surgery method.

METHODS: Retrospectively analyzed 247 patients(320 eyes)with ozil phacoemulsification and intraocular lens implantation surgery. The 247 patients were randomly divided into two groups. The two groups were given different chop method during the surgery: improved pre-chop and traditional stop and chop. The improved pre-chop group were canceled water separation steps, the ultra-long chopper were entered into the capsular bag under the rim of continuous circular capsulorhexis, by passed the intraocular lens equator then reversed the hooker upward against the posterior pole of lens and cracked the nuclear into half with the phacoemulsification hand pieces extruding the nuclear from above downward without using energy, then rotated the nuclear and repeated the chop step. The control group used the traditional stop and chop technique. Pre-surgery recording included the best-corrected visual acuity(BCVA)and corneal endothelial cell counting. Average power(AP), real ultrasound phacoemulsification time(U/Time), accumulated energy complex parameter(AECP), BSS perfusion amount and complications were recorded. And the corneal edema and corneal endothelial cell counting were observed at one week post the surgery.

RESULTS: Compared the sub-group of two groups with the same hardness of nuclear, the AP, U/Time, AECP and the BSS perfusion amount of the improved pre-phaco group were lower than the stop and chop group(P<0.05)with significant difference. Also the lose rate of corneal endothelial cell of the improved pre-phaco group was lower than the stop and chop group(P<0.05).

CONCLUSION: Using the improved pre-phaco method in the ozil phacoemulsification cataract surgery could raise the energy utilization efficiency, decrease the BBS perfusion amount during the surgery and further lower the injury to the corneal endothelial cell brought by the phacoemulsification surgery.