Anterior Segment Parameters Differences Between Acute And Chronic Primary Angle Closure Glaucoma

PurposeTo measure parameters in ocular anterior segment quantitively by using ultrasonic biological microscope(UBM)and A-ultrasound and compare the parameters differences between attack eyes of acute primary angle closure glaucoma(APACG),fellow eyes of APACG and chronic primary angle closure glaucoma(CPACG)MethodThis retrospective study enrolled thirty subjects(30 eyes)with APAC(G),twenty-nine subjects(29 eyes)with fellow eyes of APAC(G),and thirty-eight subjects(38 eyes)with CPAC(G)from December 2018 to June 2019.For every patient,UBM images capturing superior(12 o'clock),nasal(3 o'clock),inferior(6 o'clock)and temporal(9 o'clock)positions centered over the limbus are utilized.Using UBM built-in software,parameters in the four positions including iris curvature(IC),iris thickness(IT500),ciliary body thickness(CBT1),trabecular-ciliary process distance(TCPD),scleral ciliary process angle(SCPA)and trabecular-ciliary angle(TCA)were measured.The figures of every parameter obtained in four positions were averaged.The central anterior chamber depth(ACD)and pupil diameter(PD)was measured in the image captured through the nasal-temporal position centered over the pupil.Then the lens thickness(LT),axial length(AL)and relative lens position(RLP)were measured and calculated by A-ultrasound.The parameters differences among APAC(G),fellow eyes of APAC(G)and CPAC(G)were compared by statistical methodsResult1.The final value of parameters in 3 group:APAC(G):ACD(1.75±0.27)mm,IC(0.213±0.058)mm,IT500(0.356±0.525)mm,CBT1(0.547±0.072)mm,TCPD(0.511±0.071)mm,SCPA 39.06(6.97)mm,TCA(66.90±9.65)mm,LT(4.94±0.40)mm,AL(21.94±0.82)mm,RLP(2.20±0.11)mm.Fellow eyes of APAC(G):ACD(1.94±0.17)mm,IC(0.281±0.046)mm,ITsoo(0.400±0.043)mm,CBT1(0.567±0.076)mm,TCPD(0.561±0.074)mm,SCPA 39.60(5.83)mm,TCA(70.79±10.31)mm,LT(4.98±0.27)mm,AL(22.14±0.66)mm,RLP(2.19±0.08)mm.CPAC(G):ACD(1.97±0.21)mm,IC(0.235±0.051)mm,IT500(0.388±0.049)mm,CBT1(0.552±0.067)mm,TCPD(0.574±0.078)mm,SCPA 38.81(6.91)mm,TCA(75.07±10.06)mm,LT(4.99±0.39)mm,AL(22.43±0.63)mm,RLP(2.20±0.10)mm?2.The parameters of ACD(P=0.000),ITsoo(P=0.13),TCPD(P=0.001),TCA(P=0.001),AL(P=0.007)in APAC(G)group are significantly smaller than CPAC(G)group.There was no significant difference in IC,CBT1,SCPA,LT and RLP between APAC(G)group and CPAC(G)group.3.The parameters of ACD(P=0.022),IC(P<0.001),ITsoo(P=0.003)and TCPD(P=0.036)in APAC(G)group are significantly smaller than fellow eyes of APAC(G)group.There was no significant difference in CBT1,SCPA,TCA,LT,RLP and AL between APAC(G)group and fellow eyes of APAC(G)group.4.The parameter of IC(P=0.004)in fellow eyes of APAC(G)group is significantly larger than CPAC(G)group.And the parameter of AL(P=0.049)in fellow eyes of APAC(G)group is significantly smaller than CPAC(G)group.There was no significant difference in ACD,IT500,CBT1,TCPD,TCA,LT and RLP between fellow eyes of APAC(G)group and CPAC(G)group.Conclusions1.APAC(G)group has the shortest ACD and AL length,CPAC(G)group has the longest.The fellow eyes of APAC(G)group has the middle length.2.The fellow eyes of APAC(G)group has the most curved iris while APAC(G)group has the thinnest iris.Pupillary block is the main pathogenesis of APAC(G)3.APAC(G)group has the smallest TCPD and TCA,which means the ciliary bodies in APAC(G)group are the most anteriorly rotated4.There are no significant differences on LT,RLP and CBT1 among three groups.