Changes In Anterior Chamber Morphology After Laser Peripheral Iridotomy

PurposeTo prospectively quantify changes in anterior chamber morphology after laserperipheral iridotomy(LPI) using anterior segment optical coherence tomography (AS-OCT) in patients with narrow anterior chamber angle eyes.DesignProspective case series.Participants19patients with narrow angles (included fellow eyes of acute primary angle-closure patients and fellow eyes of chroic primary angle-closure glaucoma patients)whowere scheduled for LPI.MethodsAfter examations of glaucoma specialist, anterior chamber pictures by AS-OCTwere taken under common light,dark,high light,45minutes after1%pilocarpineadministration before LPI and immediately after LPI.4-6weeks after LPI, anteriorchamber pictures by AS-OCT were taken repeatedly under common light,dark,high light,45minutes after1%pilocarpine administration. Only the right eye was enrolled if botheyes were eligible. Measurements performed by a customized imageprocessing soft-ware,included anterior chamber cross-sectional aera(ACCSA),iris cross-sectional aera(ICSA), pupil diameter(PD), central anterior chamber depth (CACD)and central cornealthickness(CCT). Using the SPSS13.0statistical analysis software for statistical analysis.ResultsUnder dark,common light, high light,45minutes after1%pilocarpine administra-tion, ACCSA increased1.089,1.084,1.123,1.433mm2(P=0.000for all）after LPI;before,under1%pilocarpine administration, ACCSA decreased1.616,1.386,0.965mm2thanunder dark,common light, high light,respectively (P=0.000,0.001,0.018);after LPI,under1%pilocarpine administration, ACCSA decreased1.273,1.037,0.654mm2than under dark,common light, high light,respectively(P=0.001,0.006,0.079). It is notstatistically significant in the difference of ICSA before and after LPI (P=0.455,0.629,0.417,0.229) under dark,common light, high light, pilocarpine administer-ation,respectively);before LPI,ICSA decreased in turn under dark, common light, highlight, pilocarpine administration,but F=1.278,P=0.289;after LPI,ICSA decreased in turnunder dark,common light, high light, pilocarpine administration,also,but P<0.05onlybetween dark and high light, dark and pilocarpine administration. It is not statisticallysignificant in the difference of PD before and after LPI(P=0.654,0.537,0.682,0.821under dark,common light, high light, pilocarpine administration,respectively).afterLPI,CACD increased0.051,0.043,0.032,0.052mm under dark,common light, high light,pilocarpine administration,respectively,but P=0.028,0.073,0.057,0.133.There are nochanges in CCT after LPI(P=0.937,0.930,0.865,0.719)under dark,common light, highlight, pilocarpine administration, respectively); before or after LPI,there are no changesin CCT under dark,common light, high light, pilocarpine administration(beforeLPI,F=0.397,P=0.755,after LpI,F=0.2219,P=0.883).ConclusionIn this hospital-based study,we concluded that ACCSA increased after LPI,decreased after pilocarpine administration;but we can not determine whether LPI relievethe decreasement of ACCSA by pilocarpine administration;there is no change in ICSAafter LPI,and there is a tendency to increase in ICSA accompanied myosis;PD did notchange permanent,but it decreased further instantly after LPI; CCT did not change afterLPI or myosis.