METHORDS: Totally 70 patients(70 eyes)with age-related cataract were randomly divided into 2 groups, press-and-chop technique group(35 patients 35 eyes), phaco-chop technique group(35 patients 35 eyes). In all cases, surgery began with a clear corneal incision, capsulorhexis and hydrodissection. In the press-and-chop technique group, the superficial cortex and epinucleus were aspirated by the phaco tip, then press the center of the lens front surface with the phaco tip. The Nagahara chopper was set around the lens equator, then the phaco tip was driven into the nucleus from the main incision, pull the Nagahara chopper toward the phaco tip. The two instruments were then separated laterally to produce a complete fracture of the nucleus. In phaco-chop technique group, the phaco tip was buried in the center of the endonucleus. The Nagahara chopper was brought through the side-port incision and the equator of endonucleus was engaged by the chopper under the lower edge of the capsulorhexis and pulled toward the phaco tip. The 2 instruments were then separated laterally to produce a complete fracture of the nucleus. The U/S time, preoperative and postoperative corneal endothelial cell density, corneal endothelium loss rate, corneal edema at 1d, 7d, best corrected visual acuity before and after surgery were recorded.

RESULTS: The U/S time of press-and-chop technique group was lower than phaco-chop technique group [12.76(8.76,16.76)s vs 22.87(18.36, 27.38)s, P<0.01]. The corneal endothelial cells density in press and chop technique group was higher than that in phaco-chop technique group 1mo after operation(2133.44±348.58/mm² vs 1957.94±280.54/mm², P<0.05), and the variation rate of corneal endothelial cells in press-and-chop technique group was lower than that in phaco-chop technique group 1mo after surgery [0.15(0.08,0.22)vs 0.22(0.16, 0.28), P<0.01]. The corneal edema in press-and-chop technique group was lighter than that in phaco-chop technique group on the first day after surgery(Z=13.195, P=0.004), and corneal edema in both groups subsided on the 7d after surgery. There was no significant difference between two groups in BCVA on the first day after surgery(Z=-0.48, P=0.63).

CONCLUSION: Compared with Nagahara phaco-chop technique, press-and-chop technique is simple and safe with less complications.