| Objective:To investigate the changes of corneal refractive power(K),axial length(AL),anterior chamber depth(ACD)after small incision extraction(SMILE)by iol-master and Pentacam,and the relationship bet ween anterior chamber depth change and corneal cutting depth.The effe ctive lens position(ELP)was obtained by substituting the measured data of Pentacam and IOL Master into Holladayl formula and Haigis formul a respectively,and the comparison was made to provide accurate anterio r segment parameters for patients with corneal refractive surgery and im prove the accuracy of IOL calculation.Methods:A prospective,non-randomized study was conducted on 35 myopic patients(69 eyes)who received SMILE surgery in the Ophthal mology Center of the Second Hospital of Hebei Medical University fro m September 2020 to October 2020.The naked visual acuity,refraction,intraocular pressure,slit lamp microscope,Pentacam measurement data(corneal refractive power,central corneal thickness,anterior chamber dep th),IOL-Master measurement data(corneal refractive power,anterior cha mber depth and axial length),corneal cutting depth and other indexes of the patients undergoing SMILE surgery were recorded before and 1 mo nth and 3 months after surgery.Pair t test was used to analyze the cha nges of corneal refractive power,anterior chamber depth and axial lengt h before and after SMILE.Paired t test was used to compare the ELP calculated by Holladayl formula and Haigis formula by Iolmaster and P entacam before and after SMILE,and the significance was set at P<0.05.Pearson correlation coefficient analysis was used to investigate the rel ationship between the changes of anterior chamber depth measured by I olmaster and Pentacam before and after SMILE operation and the cuttin g depth.Results:1.Patient’s basic information(age,depth of corneal cutting,visual acuity,intraocular pressure and diopter)In this study,a total of 35 patients(69 eyes 34 right eyes,35 left eyes)were collected,including 19 males(37 eyes)and 16 females(32 eyes),aged from 18 to 36 years,with an average age of(21.43±4.72)years.The depth of corneal cutting was 67-138 μ m,with an average of(101.49±20.44)μm.Preoperative UCValogMAR was 0.88±0.25,preoperative IOP was 16±2.1 1mmHg,preoperative spherical endoscope was-4.20±1.13d,preoperative columnar endoscope was-0.40±0.30d.UCVALOGMAR was-0.04±0.04,IOP was 10.54±2.43mmHg,lunar e ndoscope was-0.13±0.52D,columnar endoscope was 0.02±0.39D,1 m onth after operation.UCvalogmar was-0.06±0.03,IOP was 10.33±1.65 mmHg,lunaroscopy was 0.10±0.42D,columnar endoscopy was-0.10±0.39D,3 months after surgery.2.Comparison of axial length(AL)before and after SMILE surgeryComparison of axial length(AL)and AL*(AL*=AL-central corne al thickness)measured by Iolmaster before and after SMILE surgeryIn the 35 myopia patients(69 eyes),the preoperative AL was 25.63±0.58mm,the postoperative AL was 25.55±0.59mm,and the postoper ative AL was 25.54± 0.59mm 3 months after surgery.The difference b etween preoperative and postoperative AL was 0.08±0.21mm,and the p reoperative AL was greater than that 1 month after surgery,with statisti cal significance(P<0.05).The difference of AL between preoperative an d postoperative 3 months was 0.09±0.16mm,preoperative AL was great er than postoperative 3 months,the difference was statistically significan t(P<0.05).There was no significant difference in AL between 1 month and 3 months after operation(P>0.05).The preoperative AL*was 25.08±0.58mm,the postoperative AL*1 month was 25.09±0.60mm,and the postoperative AL*3 months was 25.08±0.60mm.The difference betwee n preoperative and postoperative AL*1 month was-0.01±0.21mm,and the difference between preoperative and postoperative AL*1 month was not statistically significant(P>0.05).The difference of AL between pre operative and postoperative 3 months was-0.01±0.15mm,and the differ ence of AL*between preoperative and postoperative 3 months was not statistically significant(P>0.05).There was no significant difference in AL*between 1 month postoperatively and 3 months postoperatively(P>0.05)3.Comparison of anterior chamber depth(ICACD)including corneal thic kness before and after SMILE surgery3.1 Comparison of anterior chamber depth(ICACD)and anterior chamb er depth(ECACD)(ECACD=ICACD-central corneal thickness)measure d by IOLmaster before and after SMILE surgeryThe ICACD of 35 myopia patients(69 eyes)was 3.80±0.24mm b efore surgery,3.66±0.24mm 1 month after surgery,,and 3.67±0.23mm 3 months after surgery.The ICACD of 35 myopia patients before surge ry and 1 month after surgery was 0.13±0.07mm,and the ICACD befor e surgery was greater than that 1 month after surgery,with statistical si gnificance(P<0.05).The difference of ICACD between preoperative and postoperative 3 months was 0.12±0.09mm,and the preoperative ICAC D was greater than that 3 months after surgery,with statistical significa nce(P<0.05).There was no significant difference between ICACD 1 m onth after operation and ICACD 3 months after operation(P>0.05).Pre operative ECACD was 3.25±0.24mm,1 month after surgery ECACD w as 3.20±0.25mm,3 months after surgery ECACD was 3.20±0.23mm,t he difference between preoperative and postoperative ECACD was 0.06±0.05mm,preoperative ECACD was greater than 1 month after surgery,the difference was statistically significant(P<0.05).The difference of E CACD between preoperative and postoperative 3 months was 0.06±0.04 mm,and preoperative ECACD was greater than postoperative 3 months,with statistical significance(P<0.05).There was no significant differenc e in ECACD between 1 month after operation and 3 months after opera tion(P>0.05).3.2 Comparison of anterior chamber depth(ICACD)and anterior chamb er depth(ECACD)measured by Pentacam before and after SMILE surg eryThe ICACD of 35 myopia patients(69 eyes)was 3.75±0.24mm b efore surgery,3.59±0.26mm 1 month after surgery,and 3.60±0.24mm 3 months after surgery.The ICACD of 35 myopia patients before surge ry was 0.16±0.13mm,and the ICACD of 69 myopia patients before su rgery was greater than that 1 month after surgery,with statistical signifi cance(P<0.05).The difference of ICACD between preoperative and pos toperative 3 months was 0.15±0.07mm,and the preoperative ICACD w as greater than that 3 months after surgery,with statistical significance(P<0.05).There was no significant difference between ICACD 1 month after operation and ICACD 3 months after operation(P>0.05).Preoper ative ECACD was 3.20±0.25mm,1 month after operation ECACD wa s 3.13±0.26mm,3 months after operation ECACD was 3.13±0.24mm,the difference between preoperative and postoperative ECACD was 0.08±0.13mm,preoperative ECACD was greater than 1 month after operati on,the difference was statistically significant(P<0.05).The difference o f ECACD between preoperative and postoperative 3 months was 0.07±0.06mm,and preoperative ECACD was greater than postoperative 3 mo nths,with statistical significance(P<0.05).There was no significant diff erence in ECACD between 1 month after operation and 3 months after operation(P>0.05).3.3 Comparison of anterior chamber depth(ICACD)measured by IOLm aster before and after SMILE surgery and measured by Pentacam before and after SMILE surgeryThe difference between the preoperative IOLmaster(ICACD)and th e preoperative Pentacam(ICACD)was 0.04±0.07 mm,and the preoper ative IOLmaster(ICACD)was greater than the preoperative Pentacam(I CACD)average,with statistical significance(P<0.05).The difference be tween Iolmaster(ICACD)and Pentacam(ICACD)was 0.07±0.13mm,an d the difference was statistically significant(P<0.05).The difference bet ween IOLmaster(ICACD)and Pentacam(ICACD)at 3 months after surg ery was 0.07±0.08mm,and the difference was statistically significant(P<0.05).3.4 Relationship between anterior chamber depth change and corneal cut ting thicknessThere was no significant correlation between preoperative Pentacam and postoperative 1 month(ICACD)and corneal cutting depth(r=0.15,P>0.05)in 35 myopia patients(69 eyes).There was no significant cor relation between ICACD and corneal cutting depth(r=0.21,P>0.05).Th ere was no significant correlation between preoperative and postoperative ICACD(r=0.20,P>0.05)and corneal cutting depth(r=0.20,P>0.05).T here was no significant correlation between preoperative and postoperativ e 3 months(ICACD)of Master and depth of corneal cutting(r=0.14,P>0.05).4.Comparison of corneal refractive power measured by keratometer bef ore and after SMILE surgery4.1 Comparison of mean corneal refractive power(Km)measured by Iol master before and after SMILE surgeryThe Km of 35 patients(69 eyes)with myopia was 43.08±1.14D b efore surgery,38.96±1.25D 1 month after surgery,and 38.98±1.22D 3 months after surgery.The difference between the Km before surgery an d 1 month after surgery was 4.12±1.11D,and the Km before surgery was greater than that 1 month after surgery,with statistical significance(P<0.05).The difference of Km between preoperative and postoperative 3 months was 4.11±0.99D,and the preoperative Km was greater than postoperative 3 months,with statistical significance(P<0.05).There was no significant difference in Km between 1 month after operation and 3 months after operation(P>0.05).4.2 Comparison of simulated corneal refractive power(Simk)measured by Pentacam before and after SMILE surgerySimk of 35 myopia patients(69 eyes)was 42.82±1.16D before sur gery,38.86±1.27D 1 month after surgery,and 38.90±1.18D 3 months after surgery.The difference between Simk before surgery and 1 month after surgery was 3.96±1.07D,and the Simk before surgery was greater than 1 month after surgery,with statistical significance(P<0.05).The difference of Simk between preoperative and postoperative 3 months wa s 3.92±0.94D,preoperative Simk was greater than postoperative 3 mont hs,and the difference was statistically significant(P<0.05).There was n o significant difference between Simk 1 month after surgery and Simk 3 months after surgery(P>0.05).4.3 Changes of mean corneal refractive power(Km)measured by Iolma ster before and after SMILE surgery and simulated corneal refractive po wer(Simk)measured by Pentacam before and after SMILE surgeryThe preoperative difference between Km and Simk was 0.26±0.20 D,and the preoperative difference was greater than Simk,with statistica 1 significance(P<0.05).The difference between Km and Simk at 1 mon th after surgery was 0.20±0.10D,and Km at 1 month after surgery wa s greater than Simk at 1 month after surgery,with statistical significanc e(P<0.05).The difference between Km and Simk at 3 months after sur gery was 0.17±0.08D,and Km at 3 months after surgery was greater t han Simk at 3 months after surgery,with statistical significance(P<0.05)4.4 Comparison of total corneal refractive power(TCRP)and simulated corneal refractive power(Simk)measured by Pentacam before and after SMILE surgeryThe preoperative TCRP and Simk of 35 myopia patients(69 eyes)were 42.22±1.17D and 42.83±1.16D,respectively.The preoperative diff erence between TCRP and Simk was-0.61±0.17D,TCRP was less than Simk,and the difference was statistically significant(P<0.05).TCRP a nd Simk were 37.27±1.36D and 38.86±1.27D at 1 month postoperativ ely.TCRP and Simk were 37.42±1.25D and 38.90±1.18D at 3 months postoperatively.The difference between TCRP and Simk at 1 month af ter surgery was-1.60±0.37D,and TCRP at 1 month after surgery was smaller than SIMK at 1 month after surgery,with statistical significance(P<0.05).The difference between TCRP and Simk at 3 months after s urgery was-1.48±0.25d,and TCRP at 3 months after surgery was sm aller than Simk at 3 months after surgery,with statistical significance(P<0.05).5.Comparison of ELP calculated by Holladayl formula before and after SMILE surgery5.1 Comparison of ELP before and after SMILE operation calculated by IOLmaster using Holladayl formulaThe ELP of 35 myopia patients(69 eyes)was 6.16±0.19mm befo re surgery,5.54±0.12mm 1 month after surgery,and 5.54±0.01mm 3 months after surgery.The difference of Holladayl(ELP)between preope rative and postoperative 1 month was 0.63±0.18mm,and the difference of Holladayl(ELP)between preoperative and postoperative 3 months w as 0.63±0.16mm,and the difference of preoperative ELP was greater th an 1 month after surgery,with statistical significance(P<0.05).The pre operative ELP was greater than 3 months after surgery,and the differen ce was statistically significant(P<0.05).There was no significant differe nce between Holladayl(ELP)1 month after surgery and Holladayl(ELP)3 months after surgery(P>0.05).5.2 Comparison of ELP before and after SMILE operation calculated by Pentacam using Holladayl formulaThe ELP of 35 myopia patients(69 eyes)was 6.12±0.19mm befor e surgery,5.52±0.12mm 1 month after surgery,and 5.52±0.11mm 3 m onths after surgery.The difference of Holladayl(ELP)between the patie nts before surgery and Pentacam 1 month after surgery was 0.60±0.17 mm,and the difference of Holladayl(ELP)between the patients before surgery and Pentacam 3 months after surgery was 0.59±0.17mm,preop erative ELP was greater than 1 month after surgery,with statistical signi ficance(P<0.05).The preoperative ELP was greater than 3 months after surgery,and the difference was statistically significant(P<0.05).There was no significant difference between Holladayl(ELP)1 month after su rgery and Holladayl(ELP)3 months after surgery(P>0.05).5.3 Comparison of ELP before and after SMILE operation calculated by Holladayl formula between IOLmaster and PentacamThe difference between IOLMaster Holladayl(ELP)and pentacamH olladayl(ELP)before surgery was 0.04±0.04mm,and IOLmasterHollada yl(ELP)was greater than Pentacam Holladayl(ELP),the difference was statistically significant(P<0.05).Holladayl(ELP)1 month after IOL M aster and Holladayl(ELP)1 month after Pentacam were 0.01±0.01mm different,and Holladayl(ELP)1 month after IOL Master was greater th an that 1 month after Pentacam,with statistical significance(P<0.05).T he difference of Holladayl(ELP)3 months after IOL Master operation and Holladayl(ELP)3 months after Pentacam operation was 0.01±0.01 mm,and Holladayl(ELP)3 months after IOL Master operation was gre ater than that 3 months after Pentacam operation,with statistical signific ance(P<0.05).6.Comparison of ELP calculated by HAIGIS formula before and after SMILE surgery6.1 Comparison of ELP before and after SMILE operation calculated by Iolmaster using Haigis formulaThe ELP of 35 myopia patients(69 eyes)was 5.98±0.12mm befor e surgery,5.92±0.12mm 1 month after surgery,and 5.92±0.11mm 3 m onths after surgery.The difference between the ELP before surgery and 1 month after surgery was 0.06±0.04mm,and the difference between th e ELP before surgery and 3 months after surgery was 0.06±0.04mm,a nd the difference between the ELP before surgery and 3 months after s urgery was 0.06±0.04mm,and the difference between the ELP before s urgery and 3 months after surgery was greater than 1 month after surge ry,with statistical significance(P<0.05).The preoperative ELP was grea ter than 3 months after surgery,and the difference was statistically signi ficant(P<0.05).There was no significant difference in ELP between 1 month after operation and 3 months after operation(P>0.05).6.2 Comparison of ELP before and after SMILE operation calculated by Haigis formula by PentacamThe ELP of 35 myopia patients(69 eyes)was 5.97±0.12mm befor e surgery,5.89±0.12mm 1 month after surgery,and 5.90±0.12mm 3 m onths after surgery.The difference between the ELP before surgery and 1 month after surgery was 0.07±0.06mm,and the difference between th e ELP before surgery and 3 months after surgery was 0.07±0.03mm,a nd the difference between the ELP before surgery and 3 months after s urgery was 0.07±0.03mm,and the difference between the ELP before s urgery and 3 months after surgery was greater than 1 month after surge ry,with statistical significance(P<0.05).The preoperative ELP was grea ter than 3 months after surgery,and the difference was statistically signi ficant(P<0.05).There was no significant difference in ELP between 1 month after operation and 3 months after operation(P>0.05).6.3 Comparison of ELP before and after SMILE operation calculated by Haigis formula between Iolmaster and PentacamThe difference between IOLMasterHaigis(ELP)and PentacamHaigis(ELP)before surgery was 0.02±0.02mm,and the difference of IOLmast erhaigis(ELP)was greater than PentacamHaigis(ELP),and the difference was statistically significant(P<0.05).The difference of HAIGIS(ELP)1 month after IOL Master and Pentacam was 0.05±0.03mm,and the H AIGIS(ELP)1 month after IOL Master was greater than that 1 month after Pentacam,with statistical significance(P<0.05).The difference of HAIGIS(ELP)3 months after IOL Master operation and HAIGIS(ELP)3 months after Pentacam operation was 0.03±0.03mm,and the HAIGI S(ELP)3 months after IOL Master operation was greater than that 3 months after Pentacam operation,with statistical significance(P<0.05).7.Comparison of ELP calculated by Holladayl formula and Haigis form ula before and after SMILE operation7.1 Comparison of ELP calculated by Holladayl formula and Haigis for mula before and after SMILE operationComparison of Holladayl ELP and Haigiselp before SMILE showed that the difference between Holladayl(ELP)and Haigis(ELP)was 0.18±0.22mm,and Holladayl(ELP)was greater than Haigis(ELP),with stat istical significance(P<0.05).The difference between Holladayl(ELP)an d Haigis(ELP)one month after surgery was-0.39±0.16mm,and Hollad ayl(ELP)one month after surgery was smaller than Haigis(ELP)one m onth after surgery,with statistical significance(P<0.05).The difference between Holladayl(ELP)and Haigis(ELP)3 months after surgery was-0.39±0.15mm,and Holladayl(ELP)3 months after surgery was smaller than Haigis(ELP)3 months after surgery,with statistical significance(P<0.05).7.2 Comparison of ELPs calculated by Holladayl formula and Haigis for mula by Pentacam before and after SMILE surgeryComparison of Holladayl ELP and Haigiselp before SMILE showed that the difference between Holladayl(ELP)and Haigis(ELP)was 0.15±0.22mm,and Holladayl(ELP)was greater than Haigis(ELP),with stat istical significance(P<0.05).The difference between Holladayl(ELP)an d Haigis(ELP)one month after surgery was-0.37±0.17mm,and Hollad ayl(ELP)one month after surgery was smaller than Haigis(ELP)one m onth after surgery,with statistical significance(P<0.05).The difference between Holladayl(ELP)and Haigis(ELP)3 months after surgery was-0.37±0.16mm,and Holladayl(ELP)3 months after surgery was smaller than Haigis(ELP)3 months after surgery,with statistical significance(P<0.05).Conclusion:1.After SMILE,the axial shortening and the anterior chamber shor tening were caused by corneal cutting,but the anterior chamber shallow ness had no correlation with the depth of corneal cutting during the ope ration.2.IOL-MASTER can accurately measure the ocular axis after SMI LE;Total corneal refractive power(TCRP)is more accurate,followed b y simulated corneal refractive power(Simk),and finally corneal refractiv e power(Km).Pentacam and Iol-Master measurements of anterior cham ber depth can be substituted.3.Shallow anterior chamber depth after SMILE is the cause of err ors in the predicted effective intraocular lens position. |
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