AIM:To compare and evaluate the efficiency and safety of ozil torsional mode coaxial microphacoemulsification and conventional phacoemulsification in hard nuclear cataract.

METHODS: It was a prospective and randomized clinical trial. A total of 209 eyes(209 cases)with grade 4 nuclear cataract were randomly assigned into either ozil torsional mode coaxial or conventional group(104 eyes)to undergo microphaco. Best-corrected visual acuity(BCVA), intraocular pressure(IOP), central anterior chamber depth(ACD), endothelial cell count(ECC)before operation and cumulative dissipated energy(CDE), esstimated fluied used(EFU)in operation and complications were recorded. BCVA, IOP, ACD and ECC at 1 day, 1 week, 1 month after operation were compared and statistically analyzed.

RESULTS: The values of BCVA, IOP, ACD and ECC of experimental group were lower than those of conventional group before operation, there was no statistically significant differences(P>0.05). The values of CDE and EFU in ozil torsional mode coaxial group were less than that in the conventional group. The differences among two groups had statistical significance(P<0.05). The BCVA after the operation were improved in both groups, the ozil torsional mode coaxial group were better than the conventional group with the differences of BCVA≥0.3 at 1 day after operation(P=0.11). The ECC at 1 month after operation of two groups was obviously reduced(15%-30%)with a statistically significant difference in the degree of reduction.(P<0.05).

CONCLUSION: The anterior chamber stability was better in ozil torsional mode coaxial microphacoemulsification for hard nuclear cataract, with a significant reduction in the ultrasonic energy and the phaco time. The method can reduce the amount of fluid used in operation, with less ECC loss after operation, which can promote the rapid recovery of vision.