Clinical Significance Of Anterior Capsular Polishing In Cataract Surgery

Background:With the development of cataract surgery from vision restoration surgery to refractive surgery,accurate and controllable refractive state is very important for clinical.The development of material science and structure design of intraocular lens pursues better and more stable optical quality;The update of optical biological measurement equipment,femtosecond laser assisted,micro surgical incision and other technologies make the preoperative measurement and postoperative refractive state more accurate;The second generation of improved model eye theory formula and a series of artificial intelligence based intraocular lens formula are more accurate than the first agent theory formula and regression formula based on simplified eye model.It is difficult to predict and control the intraocular lens induced refractive errors such as capsular shrinkage and fiber proliferation before surgery,which can cause a series of changes in visual quality,such as astigmatism,ametropia,glare and so on.The open capsular system after phacoemulsification provides the conditions for the proliferation of the residual cells in the capsular:LEC and fibroblasts,and is widely considered as the pathological factor leading to the occurrence of posterior capsule opacification(PCO)and anterior capsule opacification(ACO).Objective:The purpose of this study was to observe the effect of standardized modern phacoemulsification combined with intraoperative mechanical polishing of anterior capsule membrane on the long-term PCO degree,intraocular lens stability and target refractive error of different types of intraocular lens.Methods:In this prospective,randomized,controlled clinical trial,patients with simple senile cataract who underwent phacoemulsification combined with intraocular lens implantation in our hospital from October 2019 to November 2020 were selected.The patients with good general condition,no operation related contraindications and successful operation were selected.Patients with diabetes,history of surgery on ocular surface and inner eye,long-term history of chronic uveitis and glaucoma,ocular trauma and high myopia,corneal astigmatism greater than 3D and failure to follow up on time were excluded.The patients underwent routine eye and systemic tests and physical examination before operation.The estimated refractive power of the eyes was recorded according to SRK-T formula.Meanwhile,the eye data related to master biometry before operation were recorded:corneal curvature,anterior chamber depth(ACD),axial length(AL),the cataract grade(recorded by anterior segment photography according to LOGS Ⅱ standard),best corrected visual acuity(BCVA).The patients were randomly divided into two groups.According to the operation time and the order of random number table,the polishing of anterior capsule was decided.All operations were performed by the same surgeon.After the removal of the cortex,the anterior capsule and equatorial part of the lens capsule were polished 360 degrees with a polisher according to the grouping results.The polishing effect depended on the operation video recording.The implanted intraocular lens was selected by the patients themselves.The master biometric data were collected at 1 week,1 month,3 months and 6 months after the operation.The anterior segment was photographed.The optometry results were expressed by spherical equivalent(SER),uncorrected visual acuity(UCVA)and best corrected visual acuity(BCVA),All the above testing items were completed by the same examiner in the same place.Results:A total of 30 eyes were followed up,including 12 males and 18 females,with an average age of 69.47 years±25.15(43-84 years).There was no significant difference in preoperative basic indexes between the two groups.There was no significant difference in anterior chamber depth,best corrected visual acuity and diopter at each time point during the follow-up period.Anterior chamber depth process difference in experimental group ACD6M-1W-0.07±09,the control group 0.00±0.90,There was no significant difference between the two groups(t=-0.409,P=0.686);Diopter process difference in experimental group SER6M-1W-0.05 ± 75,control group 0.17±0.45,there was no significant difference between the two groups(t=-1.685,P=0.103);The expected difference of diopter in the experimental group SER6M-pre-0.18± 1.00,the control group-0.13±1.20,there was no significant difference between the two groups(t=-0.255,P=0.801).6 months after operation,posterior capsular opacification classification:the experimental group had 3 patients in grade 0,14 patients in Grade 1 and 0 patients in grade 2;In the control group,there were 0 people in grade 0,8 people in Grade 1 and 5 people in grade 2.In hydrophilic group,there were 1 person in grade 0,4 persons in Grade 1 and 0 person in grade 2;In the drainage group,there were 2 people in grade 0,18 people in Grade 1 and 5 people in grade 2.By factorial analysis,there was no significant correlation between the operation mode and intraocular lens type(F=0.356,P=0.556>0.05);Main effects of surgical methods(F=4.428,P=0.045),there is a correlation between them.The main effect of intraocular lens type(F=2.127,P=0.157),there was no significant correlation.There was a moderate positive correlation between the refractive index(SER6M)and anterior chamber depth(ACD6M)6 months after surgery(r=0.518,P=0.003);There was a moderate positive correlation between the preoperative expected refractive error(SER(6M-pre))and anterior chamber depth(ACD6M)6 months after surgery(r=0.554,P=0.002).Conclusion:The mechanical polisher can make the equatorial and anterior lens capsule clean under the good red light reflection during the operation,and there is no obvious related complications during or after the operation.The accuracy of preoperative intraocular lens selection calculated by SKR-T formula is related to the stability of anterior chamber depth 6 months after surgery.The closer the postoperative anterior chamber depth is to the expected anterior chamber depth,the higher the accuracy is.The stability of anterior chamber depth is very important for the stability of diopter.During the 6-month observation period,no central posterior capsular opacification was found in different types of intraocular lenses,and the anterior capsular polishing group showed less cell proliferation than the control group.In the case of existing standardized phacoemulsification surgery and implantation of intraocular lens with sharp optical edge structure,whether the anterior capsular polishing for intraocular lens stability,and preoperative intraocular lens prediction accuracy showed no significant difference.