The Relationship Between Anterior Segment Structure And Primary Angle Closure Glaucoma And The Weight Of Structural Parameters On Angle Closure

Objective: To explore the structure characteristics of different types of PACG anterior segment and its relationship with the whole,to provide help for the early PACG classification,and to explore the weight of the changes of ocular structure parameters to the angle closure.Methods: This is a case-control study.From June 2017 to February 2018,10 cases of the control group,20 cases of acute primary angle closure glaucoma(APACG),and 20 cases of chronic primary angle closure glaucoma(CPACG)were selected from the ophthalmology outpatient of the First Affiliated Hospital of China Medical University.22 parameters of anterior segment structure and eye axis were measured by A ultrasound and ultrasound biomicroscopy(UBM).Statistical analysis was carried out on the results of the measurement,and the similarities and differences between the groups were compared,and the correlation and regression analysis between structural parameters and angle closure was performed.Results: The anterior chamber depth(ACD),angle open distance 500/750(AOD500/750),trabecular ciliary process distance(TCPD500),posterior axis length(PAL),and axis length(AL)decreased in both group APACG and CPACG group;while lens vault(LV),lens thickness(LT),maximum iris bow height(MIBH),anterior placement of ciliary body(APCB),and ciliary body thickness(CBT0)were found increased(P<0.05).Group APACG showed ACD,AOD750,iris length(IL),corneal height(CH),anterior axis length(AAL),AL,MIBH and APCB greater(P<0.05)compared with the CPACG group.There was a positive correlation between AOD750 and AOD500 in APACG group,while LV and I-Area were negatively correlated with AOD500(P<0.05),and AOD750 and AOD500 showed linear correlation(P<0.05,B=0.7).There was a linear correlation between AOD750 and AOD500 in group CPACG(P<0.05,B=0.875).Conclusion: Stenosis of anterior chamber and angle,anterior movement of iris ciliary body lens complex and shortening of posterior axis are common risk factors of PACG.APACG has shorter AAL,anterior chamber in central axis crowding and iris bulge than CPACG,which can help predict PACG classification.In addition to AOD500,AOD750 decreasing has the maximum weight of PACG angle closure,and I-Area and LV increasing has large weight of APACG angle closure.In clinical,these parameters can help the prevention and follow-up of PACG patients.