Clinical Observation Of Ultrasound Biomicroscopy In Primary Angle Closure Suspect With Laser Peripheral Iridectomy

Aims:To measure anterior segment parameters of primary angle closure suspect(PACS)patients before laser peripheral iridectomy(LPI)and after LPI by ultrasound bio microscopy(UBM),To observe the trerapeutic effect of PACS after LPI,and to explore the risk and correlative factors in PACS patients with positional angle closure after LPI.Methods: Seventy-eight eyes of acute primary angle-closure(APAC)patients(23 man,55 women)without peripheral anterior synechia were selected,the mean age of(62.41±8.53)years old.47 cases without miotic at the first visitwere examined under Indoor illumination condition(60~70 Lux)before LPI and at 1 week after LPI by UBM.Anterior segment parameters,including anterior chamber depth(ACD),angle open distance at 500μm(AOD500),peripheral iris thickness(IT),iris convex(IC),trabecular-ciliary process distance(TCPD)were observed.Each patient underwent 3 minutes UBM dark-room provocative test at 1 week after LPI,and each patient was performed in darkness(0.8~1Lux)at 6 month and 1 year after LPI by UBM,Anterior segment parameters,including ACD,AOD500,IT,IC,TCPD,iris inserti on(IRI),and the number of positional angle closure(NPAC)were observed.all data was analyzed by statistic methods.Results: 1.AOD500 and TCPDof 47 cases without miotic at the first visit were significantly increased after LPIunder Indoor illumination condition(60~70 Lux)(t1=-9.815、t2=-2.845,P1=0.000、P2=0.007),IC was significantly lowered after LPI(t1=3.291,P1=0.002)。 2.PACS Patients were examined in darkness by UBM after LPI,26 eyes(33%)occur at least one positional angle closure,19 eyes(24%)were positive in 3 minutes dark-room provocative test among them.It occurs a positive relationship between the elevation intraocular pressure and the number of positional angle closure in dark-room provocative test(r=0.84,P=0.000).3.AOD500、IT、IC were significantly(t1=-6.880、t2=12.104、t3=8.423,P1=0.000、P2=0.000、P3=0.000)changed from normal light to darkroom between positional angle closure positive group and positional angle closure negative group.4.In single factor analysis,AOD500,IT,IC,TPCD,IRIwere correlative factors of p ositive results(P1=0.003、P2=0.012、P3=0.043、P4=0.015、P5=0.024).In multiplefactor analysis,only IT,TPCD,IRIwere independent risk factors of positive results(P1=0.011、P2=0.009、P3=0.024).5.The number of cases with positional angle closure was significantly increased from 26 cases at 1 week after LPIto 39 casesat 1year after LPI(c2=4.457,P=0.035).ACD and AOD500 were significantly decreased at 6 months after LPI compared to 1 week(t1=2.712、t2=-2.240,P1=0.008、P2=0.028),LV was significantly increased at 6 months after LPI compared to 1 week(t=-2.209,P=0.030).ACD and AO D500 were significantly lowered at 1 year after LPI compared to 1 week(t1=2.990、t2=2.878,P1=0.004、P2=0.005),LV was significantly increased at 1 year after LP I compared to 1 week(t1=-4.515、t2=-3.447,P1=0.000、P2=0.001).Conclusions: 1.A certain proportion of patients with PACS after LPI appeared positional angle closure in a dark room,high risk patients could be screened by 3 minutes UBM d ark-room provocative test.Peripheral iris hypertrophy,anterior displacement of the ciliary body and iris root attachment points are independent risk factors in the early postoperative period of LPI.2.With extension of time after LPI,thicker lens thickness,shallower anterior cha mber and narrowerchamber angle,the incidence of positional angle closure in dark ness appears to be increasing.In order to avoid the PACS patients evolve to PAC G after LPI,long-term close follow-up study and intervention treatment are necessaryin high risk patients after LPI.