Clinical Application Of Phacoemulsification With A Round Blunt Phaco Tip

Background And ObjectivesCataract,the leading cause of blindness in our country and even the whole world,can’t be treated by drugs but surgery.The cataract surgery improved with the development of techniques and technologies,and phacoemulsification performed through a smaller incision with shorter time,less surgery-induced astigmatism and better visual rehabilitation has become the main choice of cataract surgeon since it was firstly introduced by Kelman in 1967.Phacoemulsification can bring visual quality improved,and at the same time,surgical complications should not be ignored.The phaco tip is significant in phacoemulsification because it is the point for release of ultrasound energy and the initiation of aspiration.Studies have shown that the surgical instruments touching the posterior capsule is the main risk factor for rupture,and even experienced cataract surgery can not completely avoid the phaco tip or surgical instruments touching the posterior capsule.The sharp phaco tip can get a good surgical efficiency,but increase the risk of posterior capsular rupture.Some researchers have proposed rounded blunt phaco tip to reduce the risk of posterior capsular rupture,and even safely polish the posterior capsule.There is no relevant randomized controlled study about whether the rounded blunt phaco tip can effectively protect the posterior capsule without increasing the risk of corneal edema,iris injury and other surgical complications,especially in the domestic ophthalmic field.We design the study to determine the influence of rounded blunt phaco tip on efficiency and safety in conventional phacoemulsification prospectively.Participants And MethodsThis study enrolled 406 eyes of 342 senile cataract patients who had undergone phacoemulsification between October 2014 and December 2015 in the Second Affiliated Hospital of Zhengzhou University.The total of eyes were divided into 2 groups according to its nuclear hardness,and phacoemulsification in each group was performed with round blunt phaco tips or standard phaco tips randomly.Clinical characteristics such as age and sex were recorded before the surgery.The best corrected vision were collected preoperatively and postoperatively at 1 day,1 month and 3 months.Intraoperative parameters included surgical time(ST),average ultrasound energy(AVE),accumulative phaco time(APT),effective phaco time(EPT),estimated fluid use(EFU).The case of posterior capsule rupture was recorded.The central corneal thickness(CCT)were evaluated preoperatively and postoperatively at 1 day using OCT(ZEISS).Results1.Clinical characteristics such as age and sex were similar in both tip groups of each nuclear hardness group(all P>0.05).2.All of the surgeries were successfully completed without explosive choroidal hemorrhage,detachment of descemet’s membrane and iris injury,in which 17 cases occurred posterior capsule rupture without fragments felling into vitreous cavity and secondary retinal detachment and other serious complications.3.The overall incidence of posterior capsule rupture was 4.18%,with 3.79% in non-hard nuclear group and 5.17% in hard nuclear group respectively.In non-hard nuclear group,the incidence of posterior capsule rupture was 1.42% and 6.52% with round blunt phaco tips or standard phaco tips respectively(P=0.035).In hard nuclear group,the incidence of posterior capsule rupture was 1.78% and 9.26% with round blunt phaco tips or standard phaco tips(P=0.225).4.All of the 17 eyes with posterior capsule rupture consisted of 11 eyes(64.71%)at the stage of phaco and 6 eyes(35.29%)at the stage of I / A respectively.The posterior capsule rupture rate was 2.71% and 1.48%,the former slightly higher than the latter,but the difference was not statistically significant(χ2=1.502,P=0.220).5.There was no statistical difference in all of intraoperative parameters between the two tip groups for patients with non-hard nuclear(P>0.05).In hard nuclear group,AVE(42.2%±5.1%,38.9%±6.4%,P=0.004)and EPT(15.53s±3.47 s,13.34s±3.18 s,P=0.001)were significantly higher in round blunt phaco tip group but the rest of intraoperative parameters showed no difference between different tip groups(P>0.05).6.The best corrected vision improved with 78.95%~85.31%、86.44%~91.84%、89.47%~93.88% postoperatively at 1 day,1month and 3 months respectively,but there was no statistical difference at any time point after surgery in both tip groups of each nuclear hardness group(all P>0.05).7.The change in CCT was similar in both tip groups for non-hard nuclear group(78.5um±50.6um,71.6um±53.3um,P=0.263).But for hard nuclear patients,the change in CCT was significantly larger in round blunt phaco tip group(220.8um±36.3um,198.4um±53.1um,P=0.011)than that of standard phaco tip group.8.The change of central corneal thickness was positively correlated with the effective ultrasound time.The Pearson correlation coefficient r=0.746,P=0.000,and the regression equation Y=11.67 X + 44.99,R2=0.556 were obtained.Conclusion1.The round blunt phaco tip is a reliable and safe option in phacoemulsification.2.The rate of posterior capsule rupture can be reduced with a round blunt phaco tip.3.The round blunt phaco tip neither decrease the efficiency nor increase the risk of corneal endothelial cell damage for non-hardcore cataract surgery.4.The round blunt phaco tip increases average ultrasound energy,effective phaco time and the extent of corneal edema for hard nuclear,but there is not bullous keratopathy.5.The incidence of posterior capsular rupture in hardcore cataract surgery is higher than that in the non-hardcore cataract surgery,the highest at the stage of phaco,followed by the I/A stage.6.Ultrasound energy is a main cause of corneal endothelial cell injury,and the degree of corneal edema is positively correlated with the use of ultrasound energy.