Study On The Morphological Differences Of Lamina Cribrosa In Primary Open-angle Glaucoma And Physiological Large Cup

Objective:Using spectral domain optical coherence tomography(SD-OCT),the morphological parameters of the lamina cribrosa of the three groups of primary open-angle glaucoma(POAG),physiological large cup(PLC),and normal eyes(Control)will be compared.The correlation and influencing factors among the lamina cribrosa morphological parameters,population background characteristics,ocular biometric parameters,retinal nerve fiber layer thickness,and visual field parameters of the three groups will be explored.And then,the application value of the lamina cribrosa morphological parameters in pathogenesis and diagnosis for POAG measured by the EDI mode of Heidelberg SD-OCT will be further evaluated.Methods:Primary open-angle glaucoma(POAG),physiological large glass(PLC)and normal eyes(Control)were used as research subjects.Five population background characteristics,including age,gender,ethnicity,basic disease history and body mass index(BMI)were recorded of the three groups.Six biometric parameters,including intraocular pressure(IOP),spherical equivalent(SE),central corneal thickness(CCT),anterior chamber depth(ACD),lens thickness(LT)and axial length(AL)were recorded through the conventional ophthalmic examinations.Six lamina cribrosa morphological parameters,including optic cup depth(OCD),lamina cribrosa anterior nerve tissue thickness(PLNT),lamina cribrosa depth(LCD),lamina cribrosa thickness(LCT),Bruch membrane opening distance(BMO diameter),and Bruch membrane opening minimum rim width(BMO-MRW),were measured through SD-OCT EDI scanning.The structural differences of the lamina cribrosa among the POAG,PLC and Control were analyzed.Meanwhile,the correlation and influencing factors among the lamina cribrosa morphological parameters,population background characteristics,ocular biometric parameters,retinal nerve fiber layer thickness,and visual field parameters of the three groups were analyzed.The diagnostic value of the lamina cribrosa morphological parameters for POAG were further explored.Results:In this cross-sectional study,a total of 106 eyes of ophthalmological patients from the First Affiliated Hospital of Kunming Medical University were included,34 eyes of 17 patients with POAG,42 eyes of 21 patients with PLC,and 30 eyes of 15 age-matched healthy people were used as Control.1.A total of 3 eyes were excluded because of unclear posterior boundary of lamina cribrosa,2 eyes in POAG and one eye in Control.The proportion of patients whose morphological parameters of lamina cribrosa could not be measured was 3/(42+34+30)=2.83%.2.Comparison of the population background characteristics in thethree groups and correlation between the morphological parameters of lamina cribrosa and them.2.1 One-way ANOVA and Chi-square test of population background characteristics:There were no significant differences in age(P=0.156),gender(P=0.207),BMI(P=0.430),ethnicity(P=0.322)and history of basic diseases affecting lamina cribrosa metabolism(P=0.079)among the three groups.2.2 Pearson correlation between population background characteristics and morphological parameters of lamina cribrosa:Age was weakly positively correlated with OCD(r=0.257,P=0.009),weakly negatively correlated with PLNT(r=-0.331,P=0.001)and BMO diameter(r=-0.296,P=0.002),moderately negatively correlated with LCT(r=-0.463,P<0.001)and BMO-MRW(r=-0.573,P<0.001).There was no significant correlation between the other background characteristics and the morphological parameters of lamina cribrosa(P>0.05).3.Comparison of the ocular biometric parameters in the three groups and correlation between the morphological parameters of lamina cribrosa and them.3.1 One-way ANOVA of ocular biometric parameters:IOP in POAG was higher than that in PLC(P=0.007)and Control(P=0.004),while there was no significant difference between Control and PLC(P=0.627);there were no significant differences in SE(P=0.362),CCT(P=0.394),ACD)(P=0.120,LT(P=0.098)and AL(P=0.069)between the three groups.3.2 Pearson correlation between ocular biometric parameters and lamina cribrosa morphological parameters.i)OCD:IOP was weakly positively correlated with it(r=0.312,P=0.001),and AL weakly negatively(r=-0.245,P=0.012).ii)LCD:IOP was weakly positively correlated with it(r=0.305,P=0.002),and AL weakly negatively(r=-0.223,P=0.024).iii)LCT:IOP was weakly negatively correlated with it(r=-0.311,P=0.001).iv)BMO diameter:A1 was moderately positively correlated with it(r=0.425,P<0.001).v)BMO-MRW:A1 was weakly positively correlated with it(r=0.331,P=0.001),and IOP weakly negatively(r=-0.209,P=0.035).vi)PLNT:There was no correlation between ocular biometric parameters and PLNT(P>0.05).4.One-way ANOVA of the morphological parameters of lamina cribrosa in three groups.ⅰ)OCD:POAG was significantly deeper than Control(P<0.001)and PLC(P=0.002),and PLC was also deeper than Control(P=0.004).ⅱ)PLNT:POAG and PLC was thinner than Control(both P<0.001),and there was no significant difference between POAG and PLC(P=0.441).ⅲ)LCD:POAG was deeper than PLC and Control(both P<0.001),and there was no significant difference between PLC and Control(P==0.056).ⅳ)LCT:POAG was significantly thinner than PLC and Control(both P<0.001),and PLC was also thinner than Control(P<0.001).ⅴ)BMO diameter:POAG and Control were narrower than PLC(both P<0.001),but there was no statistical significance between POAG and Control(P=0.786).ⅵ)BMO-MRW:POAG was significantly narrower than PLC and Control(both P<0.001),PLC was also narrower than Control(P<0.001).Superior BMO-MRW:POAG was significantly thinner than PLC and Control(both P<0.001),and PLC was also thinner than Control(P=0.005).Inferior BMO-MRW:POAG was significantly thinner than PLC and Control(both P<0.001),and PLC was also thinner than Control(P=.001).vii)Average RNFL(G):POAG was significantly thinner than PLC and Control(both P<0.001),and there was no significant difference between PLC and Control(P=0.852).Superior RNFL:POAG was significantly thinner than PLC and Control(both P<0.001),and the difference between PLC and Control was not statistically significant(P=0.604).Inferior RNFL:POAG was significantly thinner than PLC and Control(both P<0.001),and the difference between PLC and Control was not statistically significant(P=0.865).5.Pearson correlation between the morphological parameters of the lamina cribrosa and the traditional structural parameter RNFL.i)Average RNFL(G):OCD and LCD were moderately negatively correlated with it(r=-0.471,P<0.001;r=-0.484,P<0.001,respectively);PLNT and BMO diameter were weakly negatively correlated with it(r=0.238,P=0.015;r=0.326,P=0.001,respectively);LCT was moderately positively correlated with it(r=0.682,P<0.001).BMO-MRW was highly positively correlated with RNFL(r=0.762,P<0.001).ii)Local RNFL:Superior BMO-MRW was moderately positively correlated with superior RNFL(r=0.667,P<0.001),and inferior BMO-MRW was highly positively correlated with the inferior RNFL(r=0.730,P<0.001).6.Multiple linear regression of the influencing factors of the population background characteristics and the ocular biometric parameters on the morphological parameters of the lamina cribrosa.i)OCD:IOP(P=0.006)and SE(P=0.042)were positively correlated with OCD.OCD(μm)=-192.848+14.207×IOP(mmHg)+15.918×SE(D).ⅱ)PLNT:Age(P=0.001)and CCT(P=0.033)were negatively correlated with PLNT.PLNT(μm)=394.192-1.362×age(year)-0.376xCCT(μm).ⅲ)LCD:IOP was positively correlated with LCD(P=0.008).LCD(μm)=349.974+11.084xIOP(mmHg).iv)LCT:Gender was positively correlated with LCT(P=0.003),while age(P<0.001),IOP(P<0.001)and basic disease history(P<0.001)were negatively correlated with LCT.LCT(μm)-365.044-0.768×age(year)-2.637×IOP(mmHg)-18.792×based disease+13.892xgender.v)BMO diameter:CCT was positively correlated with BMO diameter(P<0.001),while SE was negatively correlated with BMO diameter(P<0.001).BMO diameter(μm)=60.435-68.367×SE(D)+2.881×CCT(μm).vi)BMO-MRW:AL was positively correlated with BMO-MRW(P<0.001),while age(P<0.001),basic disease history(P<0.001)and BMI(P=0.003)were negatively correlated with BMO-MRW.BMO-MRW(μm)=90.255+23.175×AL(mm)-74.307×basic disease history-2.564xage(year)-6.737×BMI(kg/m2).7.Pearson correlation between lamina cribrosa morphological parameters and visual field parameters.OCD was moderately negatively correlated with MD and VFI(r=-0.498,P<0.001;r=-0.427,P<0.001,respectively).LCD was moderately negatively correlated with MD and VFI(r=-0.507,P<0.001;r=-0.437,P<0.001,respectively).LCT was moderately positively correlated with MD and VFI(r=0.636,P<0.001;r=0.579,P<0.001,respectively),BMO-MRW was moderately positively correlated with MD and VFI(r=0.677,P<0.001;r=0.649,P<0.001,respectively).PLNT was weakly positively correlated with MD and VFI(r=0.260,P=0.008;r=0.214,P=0.034,respectively),while,BMO diameter had no correlation with visual field parameters(P>0.05).8.Analysis of ROC curve of lamina cribrosa morphological parameters on the diagnostic efficiency for POAG.OCD,LCD,PLNT,LCT and BMO-MRW have higher diagnostic accuracy(ie,AUC greater than 0.5).Among the lamina cribrosa morphological parameters,AUC of LCT was 0.996(P<0.001),the corresponding to the best critical value of POAG was 267.0μm,with sensitivity 1.000 and specificity 0.915;AUC of BMO-MRW was 0.929(P<0.001),the corresponding to the best cut-off value of POAG was 227.7μ.m,with sensitivity 0.875 and specificity 0.957.LCT and BMO-MRW had higher diagnostic accuracy for POAG.LCT had the best diagnostic efficiency,followed closely by BMO-MRW,but slightly weaker than RNFL.Conclusion:1.The lamina cribrosa morphological parameters have high structure-structure correlation with RNFL,the traditional structural parameters of optic nerve head,and high structure-function correlation with MD and VFI,the functional parameters of visual field.Furthermore,the lamina cribrosa morphological parameters have an important diagnostic value for POAG.2.There is a small overlap between the lamina cribrosa morphological parameter values of PLC and POAG,which requires long-term follow-up observation.3,EDI-OCT can detect the lamina cribrosa structure clearly and accurately,which provides new evidence for the diagnosis,treatment and follow-up for glaucoma.