| Background And ObjectivesCataract is not only the main reason of blindness in most countries of the world,but also the first cause of blindness in China,mainly occur in elderly people aged 50 years or above.However,the pathogenesis of cataract is not completely clear,there is no breakthrough in any kinds of drugs.The only way to cure cataract is still surgery.Since ancient times,the methods of cataract surgeries go through needle couching,ICCE,ECCE,phacoemulsification and femtosecond laser assisted phacoemulsification.Phacoemulsification has been applied since 1967,with its smaller incision,shorter operation time,less injury and quicker recovery of visual acuity,rapidly becomes the the main surgical treatment for cataract.Although phacoemulsification has been more mature,besides,the complications reduce,and the range of surgical indications gradually expands,a part of complicated cataracts have been effectively treated,but the damage to the corneal endothelial cells is still a prominent problem.Especially in cataracts with shallow anterior chamber,anterior chamber space is narrow,the difficulty and risk of surgery increase significantly,if combined with low corneal endothelial cell counts,it may further increase,which more likely cause the damage to corneal endothelial cells.Corneal endothelial cell damage can lead to corneal edema,decreased vision,seriously affect the efficacy of surgery,even corneal decompensation which may need corneal transplantation.How to reduce the damage to corneal endothelial cells in phacoemulsification is what surgeons focus.23 G anterior vitrectomy is a kind of minimally invasive vitrectomy in recent years.According to the literature,it can effectively reduces the pressure of the posterior chamber,and makes the lens-iris septum backed up.In theory,phacoemulsification with the auxiliary of 23 G anterior vitrectomy can significantly increase the distance between surgical instruments with manipulation and corneal endothelial,effectively reduce the damage of corneal endothelial cells,but it has not been reported so far.This study adopts simple phacoemulsification and 23 G anterior vitrectomy combined with phacoemulsification for the treatment of cataract with shallow anterior chamber and low corneal endothelial cell density,comparing the effects of two methods,in order to reduce the damage of corneal endothelial cells to the utmost,and provide better and faster postoperative visual acuity for the patients.Materials and Methods30 cases(34 eyes)with a preoperative ECD of less than 1000/mm2 and shallow anterior chamber were selected in the Second Affiliated Hospital of Zhengzhou University form January 2012 to December 2015.If combined with 23 G anterior vitrectomy,it would need much more expense.Therefore,according to the voluntary principle,30 cases were divided into two groups: combined surgery group and Phaco group.In which 16 cases(19 eyes)underwent 23 G anterior vitrectomy combined with phacoemulsification(combined surgery group),14 cases(15 eyes)underwent phacoemulsification(Phaco group).The BCVA and corneal edema were examined at postoperative 1 day,1 week and 3 months.ECD was recorded preoperative and postoperative 3 months.The regression time of corneal edema,intraoperative and postoperative complications were observed.Results1.The basic data of two groups: Patients’ age,gender,preoperative ECD,nucleus hardness and ACD had no statistical difference between combined surgery group and Phaco group(all P>0.05).2.Preoperative and postoperative BCVA of two groups: Preoperative BCVA of the combined surgery group and the Phaco group had no statistical difference(χ2=0.028,P=0.866>0.05).Compared with preoperative,the BCVA at postoperative 1 day in the combined surgery group improved significantly(χ2=8.208,P=0.004<0.05);the Phaco group did not improve(χ2=0.271,P=0.603>0.05).The BCVA at postoperative 1 week in the combined surgery group and the Phaco group were all better than those before surgery,with statistical difference(χ2=20.928,6.404;P=0.000,0.011<0.05).The BCVA at postoperative 1 day and 1 week in the combined surgery group were better than those in the Phaco group(χ2=4.142,3.933;P=0.042,0.047<0.05).The BCVA at postoperative 3 months in the combined surgery group and the Phaco group were all better than those before surgery,with statistical difference(χ2=21.990,15.353;P=0.000,0.000<0.05).The BCVA at postoperative 3 months between the combined surgery group and the Phaco group had no statistical difference(χ2=0.223,P=0.637>0.05).3.Postoperative corneal edema of two groups: The rate of corneal edema in the combined surgery group and the Phaco group were 68.4% and 86.7%,respectively,with no statistical difference(P=0.257>0.05).The corneal edema in the combined surgery group and the Phaco group were mainly in grade one and grade two at postoperative 1 day,respectively,with statistical difference(χ2=4.874,P=0.027<0.05).The corneal edema at postoperative 1 week between the combined surgery group and the Phaco group had no statistical difference(χ2=1.779,P=0.182>0.05).The mean regression time of corneal edema in the combined surgery group and the Phaco group were 1 day and 4 days,respectively,with statistical difference(Ζ=-2.336,P=0.019<0.05).4.Postoperative ECD and corneal endothelial cell loss rates of two groups: The postoperative ECD at postoperative 3 months in the combined surgery group and the Phaco group were(758.82±27.14)/mm2 and(775.76±20.91)/mm2,respectively,with no statistical difference(t=-0.495,P=0.624>0.05).The rates of corneal endothelial cell loss at postoperative 3 months in the combined surgery group and the Phaco group were(7.86±0.76)% and(13.39±0.47)%,respectively,with statistical difference(t=-6.211,P=0.000<0.05).5.Intraoperative and postoperative complications: All cases did not occurr including posterior capsule rupture,vitreous body prolapse and other complications.During the follow-up period of 3 months,there was no severe complications such as corneal decompensation,low intraocular pressure,retinal detachment and so on.Conclusions1.For cataracts with shallow anterior chamber and low ECD,combined with 23 G anterior vitrectomy can significantly reduce the difficulty and risk of phacoemulsification,and make the operation safer.2.Compared with simple phacoemulsification,23 G anterior vitrectomy combined with phacoemulsification has less damage to the corneal endothelial cells,the degree of postoperative corneal edema is lighter,and the visual acuity recover faster after surgery.3.For different cataracts with shallow anterior chamber and low ECD,according to the patients’ specific condition and economic ability to choose different surgical methods.4.Compared with simple phacoemulsification,23 G anterior vitrectomy combined with phacoemulsification is more suitable for cataracts with shallow anterior chamber and low ECD.However,the sample of this study is small,the follow-up time is short,the research results need multicenter,large sample randomized clinical trials to prove.Besides,the long-term effect is yet to be further confirmed. |
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