A Clinical Study Comparing The Biological Parameters Of The Atrial Angle And Ciliary Body In Two Types Of Closed-angle Glaucoma

Objective: To quantify the atrial angle and ciliary body-related parameters in patients with acute primary angle-closure glaucoma(APACG)and chronic primary angle-closure glaucoma(CPACG)using ultrasound biomicroscopy(UBM),to compare the differences in these anterior segment biology parameters between patients with APACG and CPACG,and to understand the differences in the anatomy of the two different clinical presentations of angle-closure glaucoma and their relationship to the pathogenesis.Methods: A total of 56 eyes were selected for this study,including 23 eyes in the APACG group and 33 eyes in the CPACG group.The clearer UBM images collected from each patient were retrieved,and quantitative measurements were analyzed using the built-in software of UBM.The biological parameters measured included: atrial angle opening distance(AOD500),trabecular-ciliary distance(TCPD),iris-ciliary distance(ICPD),scleral-ciliary angle(SCPA),trabecular-ciliary angle(TCA),ciliary body thickness at 500 μm(CBT500),and ciliary body length 500(CBL500).Results: Parameter measurements in the PACG group were AOD500(0.0482±0.0476)mm,TCPD(0.6374±0.1104)mm,ICPD(0.1105±0.0764)mm,SCPA(35.1047±3.4838)°,TCA(60.0963±8.2962)°,and CBT500(1.0520±0.1482)mm,CBL500(0.9877±0.2506)mm.The parameters measured in the CPACG group were AOD500(0.1232±0.0989)mm,TCPD(0.7102±0.1448)mm,ICPD(0.1194±0.0942)mm,SCPA(38.2800±4.6263)°,TCA(66.4780±11.8301)°,CBT500(1.1539±0.1264)mm,CBL500(1.0065±0.2689)mm.The AOD500,TCPD,SCPA,TCA,and CBT500 were smaller in the APACG group than in the CPACG group,and the differences were statistically significant(P<0.05);while the differences in ICPD and CBL500 between the APACG and CPACG groups were not statistically significant.Conclusion: There are differences in the atrial angle and ciliary body structure between patients with acute primary closed-angle glaucoma and those with chronic primary closed-angle glaucoma.Patients with acute closed-angle glaucoma have narrower atrial angles and a more anteriorly rotated,thinner ciliary body than patients with chronic closed-angle glaucoma.Differences in ciliary body position and morphology may be important factors in the different forms of attack in the two primary forms of closed-angle glaucoma.