| Purpose To analyze the changes of the Lamina cribrosa(LC)thickness in high myopia and identify the characteristics that are associated significantly with the thinning of the LC;To characterize the nonjuxtapapillary deep-layer microvasculature dropout(NJMvD),analyze the incidence of this NJ-MvD in high myopic eyes,and to investigate the factors related to NJ-MvD;To investigate the distribution characteristics of J-MvD in high myopic eyes.To analyze the relationship between LC thickness and high myopic eyes with open angle glaucoma(OAG),and to verify the reliability that using LC thickness as a new diagnostic index for high myopic eyes with OAG;To investigate the distribution characteristics of J-MvD in high myopic eyes with OAG,and to explore the relationship between NJ-MvD and high myopic eyes with OAG.Method One hundred ninety-four high myopic eyes(194 participants)with βparapapillary atrophy(βPPA)γ-zone were divided into three subgroups according to the axial length:26mm～27.9mm(1 group),28mm～29.9mm(2 group),30mm～34.1mm(3 group).The differences of central retinal vessel trunk(CRVT)shift index,LC thickness,LC depth,focal LC defect(FLCD),posterior staphyloma(PS),externally oblique border distance(EOBD),Bruch’s membrane opening distance(BMOD)and NJ-MvD were compared among the groups.Multivariate stepwise linear regression analysis was used to investigate the factors associated with the LC thickness;According to the condition of NJ-MvD,these high myopic eyes were divided into two groups:with NJ-MvD group(NJ-MvD group,57 eyes)and without NJ-MvD group(control group,132eyes);The differences in the structural parameters of optic nerve head,age,gender and axial length were compared among two groups.Logistic regression analysis was used to explore the factors affected NJ-MvD;Agreement analysis of the angle location between the NJ-MvD and the longest βPPA was performed by Bland-Altman plots;Polar plots was used to compared the angle location between NJ-MvD and the longest βPPA;Thirty-three high myopic eyes with OAG(OAG group,33 participants)and another 33 age and axial length matched eyes without OAG(control group,33 participants,1:1 propensity score),the differences of peripapillary microstructures functional index were compared among two groups,such as CRVT shift index,LC thickness,LC depth,cup-to-disc ratio,J-MvD,mean visual field defect(MD);Logistic regression analysis was used to explore the factors affected the diagnosis of OAG in high myopic eyes;Receiver operating-characteristics curve(ROC)and the area(AUC)under ROC were calculated for LC thickness,MD and cup-to-disc ratio;Frequencies and the distribution characteristics of J-MvD were investigated,and agreement analysis and corresponding angle location between the longest βPPA and J-MvD were displayed by Bland-Altman plots and Polar plots.Results The greater the CRVT shift index,thinner the LC,larger BMOD,longer EOBD,and higher prevalence of FLCD,PS,temporal scleral step,and NJ-MvD were observed in longer axial length group;A stepwise linear regression analysis revealed that the LC thickness was associated with FLCD(B=11.701,P<0.001),temporal scleral step(B=8.09,P=0.042),EOBD(B=-0.009,P<0.001),CRVT shift index(B=-20.892,P=0.016);Logistic regression analysis revealed that NJ-MvD was affected by aging(OR=1.229,95%CI:1.08-1.398,P=0.002),longest βPPA distance(OR=1.218,95%CI:1.123 to 1.321,P<0.0001)、PS presence(OR=3.072,95%CI:1.265 to 7.459,P=0.013).There was a good agreement between the angle location of the longestβPPA and NJ-MvD(mean difference:-8.6°;95%limits of agreement of the difference ranged from-91.7° to-74.5°).Polar plots demonstrate the corresponding location of NJ-MvD and the longest βPPA,both NJ-MvD and the longest βPPA were located in temporal retina mostly.Compared with control group,OAG group had a larger CRVT shift index,a thinner LC,a deeper LC anterior surface(all P<0.05),and a higher incidence of temporal scleral step and FLCD(all P<0.05).J-MvD was observed in 93.9%of the OAG group,whereas none of the control group exhibited J-MvD(P<0.05);Logistic regression analysis revealed that the diagnosis of high myopia with OAG was affected by the percent of CRVT off Bruch’s membrane opening center(OR=1.368,95%CI:1.039-1.801,P=0.026)and LC thickness(OR=0.776.95%CI:0.627-0.959,P=0.019);As a new index,the diagnostic performance of LC thickness(sensitivity 87.9%,specificity 93.9%,AUC 0.975,cut-off point 120.05 μm)was better than MD(sensitivity 81.8%,specificity 72.7%,AUC 0.807,cut-off point Value 7.15)and cupto-disk ratio(sensitivity 84.8%,specificity 72.7%,AUC 0.874,cut-off value 0.6);Bland-Altman plots showed the good agreement of angle location between the longestβPPA and J-MvD(mean difference:-2.8°,95%limits of agreement of the difference ranged from-64.5° to 58.8°);Polar plots demonstrate the corresponding location of JMvD,and the location of longest βPPA,both the longest βPPA and J-MvD were located in temporal retina.Conclusions The LC thickness of high myopic eyes tend to be thin with the enlargement of the axial length.FLCD,temporal scleral step of the optic disc,CRVT shift and EOBD enlargement contribute to the results of LC thinning;The optic nerve head suffered from mechanical and hemodynamic damage attributed to LC thinning and shift and J-MvD,which were main factors resulted in high myopia with OAG;LC thickness can be used as a sensitive signal for OAG diagnosis,especially suitable for high myopia,which was coexistent the abnormal distribution of retinal nerve fiber layer thickness and the misjudgment of cup-to-disc ratio.Ophthalmologists should carefully consider the existence of glaucomatous optic nerve damage in myopic eyes with a thickness of LC 120.05 μm or less;NJ-MvD,a manifestation of the deformation and displacement of the sclera adjacent to the optic nerve head,detected in high myopia was related to aging,the longest βPPA distance and PS presence,which performs a form of damage to some extent in the blood supply of parapapillary. |
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