基于角膜生物力学效应及视网膜血流密度比较FS-LASIK和SMILE治疗近视散光的临床研究

Clinical Study on Treatment of Myopia and Astigmatism Based on Corneal Biomechanical Effects and Retinal Blood Flow Density:FS-LASIK vs.SMILE

目的探讨飞秒激光辅助准分子激光原位角膜磨镶术(femtosecond laser in situ keratomileusis,FS-LASIK)与飞秒激光小切口角膜基质透镜取出术(small incision lenticule extraction,SMILE)治疗近视散光对患者角膜生物力学效应、视网膜血流密度的影响。方法选取2018年6月至2021年3月,近视散光患者400例,依据手术方式不同将患者分为低散光+SMILE组(A组)、低散光+FS-LASIK组(B组)、中高散光+SMILE组(C组)、中高散光+FS-LASIK组(D组),四组均采用飞秒激光制作角膜瓣,制作光参数为重复频率500 kHz、脉冲能量130 nJ,之后A组和C组行SMILE,采用显微分离器分离透镜并取出;B组和D组行FS-LASIK准分子激光频率250 Hz、脉冲能量130 nJ。比较四组患者术前及术后3、6、12个月的视觉质量参数LogMAR视力、高阶相差(higher order difference,HOA)、角膜荧光素染色(corneal fluorescencein staining,CFS)染色评分、中央角膜厚度改变率、角膜滞后量(corneal hysteresis,CH)、角膜阻力因子(corneal resistance factor,CRF)、角膜内皮细胞密度(corneal endothelial cell density,CD)、变异系数(variable coefficient,CV)、六角形细胞百分比、平均细胞面积及黄斑区浅层视网膜血流密度(superficial retinal blood flow density in macula,SCP)和视盘周围视网膜神经纤维层厚度(thickness of retinal nerve fiber layer around optic disc,RNFL)等指标差异。结果术前,各组患者LogMAR视力、HOA、CFS评分、中央角膜厚度改变率、CH、CRF、CD、CV、六角形细胞百分比、SCP及RNFL等指标差异无统计学意义(P>0.05)。与术前比较,术后3、6、12个月,各组LogMAR视力、HOA、CFS评分、中央角膜厚度改变率、CH、CRF等指标均显著改善(P<0.05),而CD、CV、六角形细胞百分比、SCP及RNFL等指标比较差异无统计学意义(P>0.05)。术后3、6个月各时间点,A组与B组及C组与D组在HOA、CFS评分、中央角膜厚度改变率、CH和CRF等指标相互比较差异具有统计学意义(P<0.05),而其他各指标比较差异无统计学意义(P>0.05)。结论SMILE和FS-LASIK对近视散光患者均具有良好的疗效,安全系数高,而散光程度不影响手术疗效;但SMILE对患者HOA、干眼症状、中央角膜厚度改变率及角膜生物力学变化的影响更小。

Objective To explore the effect of femtosecond laser in situ keratomileusis(FS-LASIK)and femtosecond laser small incision lenticule extraction(SMILE)on corneal biomechanics and retinal blood flow density in patients with myopic astigmatism.Methods Totally 400 patients with myopic astigmatism treated over the period from Jun.2018 to Mar.2021 were selected and divided into four groups by surgical methods:low astigmatism+SMILE group(Group A),low astigmatism+FS-LASIK group(Group B),medium to high astigmatism+SMILE group(Group C),medium to high astigmatism+FS-LASIK group(Group D).Femtosecond laser was used to make corneal flap in all four groups.The optical parameters were given as below:500 kHz(repetition rate)and 130nJ(pulse energy).The patients in Group A and C were given SMILE,and the lens were separated and removed by a microscopic separator.The patients in Group B and D were given FS-LASIK with an excimer laser frequency of 250 Hz and pulse energy of 130 nJ.The visual quality parameters LogMAR vision,higher order difference(HOA),corneal fluorescencein staining(CFS)staining score,central corneal thickness change rate,corneal hysteresis(CH),corneal resistance factor(CRF),corneal endothelial cell density(CD),variable coefficient(CV),percentage of hexagonal cells,mean cell area and superficial retinal blood flow density in macula(SCP)and thickness of retinal nerve fiber layer around optic disc(RNFL)were compared among the four groups before and 3,6 and 12 months after the operation respectively.Results Before the surgery,there was no significant difference in LogMAR visual acuity,HOA,CFS score,central corneal thickness change rate,CH,CRF,CD,CV,percentage of hexagonal cells,SCP or RNFL among all groups(P>0.05).The LogMAR visual acuity,HOA,CFS score,central corneal thickness change rate,CH,CRF and other indexes were significantly improved in all groups 3,6 and 12 months after the operation.There was no significant difference in CD,CV,percentage of hexagonal cells,SCP or RNFL among the groups(P>0.05).Significant differences existed in HOA,CFS score,central corneal thickness change rate,CH and CRF between Group A and B,and between Group C and D 3 or 6 months after the surgery(P<0.05),but there was no significant difference in other indexes(P>0.05).Conclusions Both SMILE and FS-LASIK are effective and safe for myopic astigmatism,and the degree of astigmatism does not affect the surgical efficacy.However,SMILE has less effect on HOA,dry eye symptoms,central corneal thickness change rate and corneal biomechanical changes.