Appositional angle closure in fellow eyes of acute primary angle closure after laser peripheral iridotomy

Abstract

Objective To investigate the frequency and anatomical characteristics of appositional angle closure after laser peripheral iridotomy in the fellow eyes of acute primary angle closure.Methods Prospective study.Fifty-four fellow eyes of acute primary angle closure without peripheral anterior synechia after laser peripheral iridotomy were studied.Mean age of (67.1±7.2)years (range 54-83 years).Uhrasounic biomicroscopy (UBM) were performed in darkness.Qualitative analysis of appositional angle closure and quantitative measurements of the angles from UBM images were taken.It was compared between the eyes of positive and negative appositional angle closure groups in intraocular pressure,gonioscopy and UBM parameters,including angle opening distance500 (AOD500),angle recess area750 (ARA750),trabecular-iris angle (T-I angle),trabecular-ciliary process distance (TCPD),peripheral iris thickness (IT1),iris-zonule distance (IZD),the position of iris insertion and central anterior chamber depth (ACD).All analyses were performed using a two-tailed Student's t test and two independent samples rank sum tests of SPSS 12.0 statistical software.Results Twenty patients (37％) were found to have appositional angle closure in at least one quadrant from UBM images in darkness after laser peripheral iridotomy,The indexes showing angle open degree (AOD500,ARA750,T-I angle) and the index showing ciliary body position (TCPD) in appositional angle closure positive group were less than those in negative group (t=11.741,11.089,12.175 and 4.349 respectively,P＜0.01).The index showing iris configuration and position IT1 in appositional angle closure positive group was more than that in negative group (t=-3.300,P=0.002).There were no significant differences in 1ZD,position of iris insertion and center anterior chamber depth between the two groups (t=-1.880,P=0.066; Z=-1.423,P=0.155; and t=0.072,P=0,942 respectively).Conclusion The fellow eyes of acute primary angle closure still appear appositional angle closure in darkness proportionally after laser peripheral iridotomy.The narrower angle,the more anterior position of the ciliary body,and the thicker peripheral iris,are the anatomical characteristics associated with appositional angle closure after laser peripheral iridotomy.It suggests the possibility of chronic angle closure development in the eyes having these anatomical characteristics in acute primary angle closure after laser peripheral iridotomy. Key words: Angle closure,acute primary; Iridotomy,peripheral; Angle closure,appositional