AIM: To analyze the efficacy of bevel-up phaco chop versus bevel-down phaco drill in the treatment of hard nuclear cataract and the influence on corneal endothelium.

METHODS: Between August 2018 and April 2020, 94 patients(104 eyes)with hard(grade Ⅳ-Ⅴ)nuclear cataract treated with phacoemulsification were enrolled in this retrospective study. Among them, 50 eyes treated by bevel-up phaco chop were included in the control group, while 54 eyes treated by phaco drill technique were included in the observation group. The time of using ultrasound, ultrasonic energy and accumulated energy complex parameter in the two groups were recorded. The best corrected visual acuity(BCVA)in 7d, corneal endothelial cell count in 2mo, the proportions of normal hexagonal cells and the degree of corneal edema in 7d were compared between the two groups.

RESULTS: The time of using ultrasound, ultrasonic energy and accumulated energy complex parameter of the observation group were shorter and lower than those of the control group(P<0.05). The BCVA of both groups increased after operation, and the observation group had higher BCVA than the control group at the same time(P<0.05). In 1 and 2mo, the corneal endothelial cell counts and the proportions of normal hexagonal cells in both groups were lower than those before operation. Meanwhile, the corneal endothelial cell count and the proportions of normal hexagonal cells in the observation group were higher than those in the control group(P<0.05). Besides, corneal edema was milder in the observation group than in the control group at 24h and 7d after operation(P<0.05).

CONCLUSION: Compared with bevel-up phaco chop, phaco drill can significantly shorten the time of using ultrasound, reduce ultrasound energy, promote visual recovery, and reduce corneal endothelial cell damage.