A comparative study between reverse chopper-assisted prechop phacoemulsification and stop-and-chop phacoemulsification for cataract with IV degree hard nucleus

Abstract

Background The pre-chop technique can decrease the use of ultrasound power, and thus reducing the loss of corneal endothelial cells (CECs) and injuries of other intraocular structures.Many currently developed manual pre-chop techniques restrict the wide application of the pre-chop technique because of their intrinsic disadvantages.The present study describes a manual pre-chop technique for pre-slicing the lens nucleus by using a novel reverse chopper, which has not been reported yet. Objective This study was to compare the efficacy and safety of pre-chop technique using a reverse chopper and stop-and-chop phacoemulsification technique on Ⅳ degree hard nucleus cataract. Methods A prospective clinical-controlled interventional study was performed.Thirty-two eyes of 32 cataract patients with Ⅳ degree of nucles were enrolled in People's Hospital of Hetian District from March 2015 to January 2016.The patients were randomized into the prechop group and matched stop-and-chop group according to random number table.The self-made reverse chopper-assisted pre-chop phacoemulsification surgery and stop-and-chop phaco surgery were performed on the eyes of corresponding groups, respectively.The ultrasound power, effective phaco duration, corneal endothelium loss rate, the eye number of different grade of cornea edema after operation and vision outcome were compared between the two groups.Written informed consent was obtained prior to relevant examination and surgery. Results The mean effective Phaco durations were 42.56 (39.31, 45.81) seconds and 78.63 (73.85, 83.40) seconds in the prechop group and stop-and-chop group, with a significant difference between them (Z=-4.937, P=0.000). The eye number with different degree of best corrected visual acuity (BCVA) was significantly different between the two groups, at postoperative day 1 and day 3 (P=0.013, 0.033). The number of corneal endothelial cells (CECs) 1 month after surgery was (2 026.05±154.03)/mm2 in the prechop group, and the number was (1 866.50±117.16)/mm2 in the stop-and-chop group, with a significant difference between them (t=3.298, P=0.003). The CECs loss rate was (13.36±2.85) % in the prechop group, which was lower than (25.77±3.81) % in the stop-and-chop group (t=-6.996, P=0.000). The eye number with different degree of corneal edema was significantly decreased in the prechop group compared with the stop-and-chop group at postoperative day 1 and day 3 (P=0.001, 0.002). Conclusions Compared with the stop-and-chop phaco technique, a reverse chopper-assisted pre-chopping technique can decrease the intraoperative complication, lighten the postoperative damage of CECs and accelerate visual rehabilitation in hard nucleus cataract eyes. Key words: Cataract/surgery; Phacoemulsification/methods; Lens nucleus, crystalline/surgery; Treatment outcome; Comparative study; Pre-chopping technique; Stop-and-chop technique; A reverse chopper; Humans