scholarly journals Biometric Indicators of Anterior Segment Parameters Before and After Laser Peripheral Iridotomy by Swept-Source Optical Coherent Tomography

Author(s):  
Bo Yu ◽  
Kang Wang ◽  
Xiaoli Xing

Abstract Background Primary angle closure glaucoma (PACG) is the most common type of glaucoma in China. Laser peripheral iridotomy (LPI) is the primary choice to treat PAC. We aim to evaluate the changes and to find the biometric indicators of anterior segment parameters before and after laser peripheral iridotomy (LPI) in primary angle closure (PAC) eyes using swept-source optical coherent tomography (OCT). Methods LPI was performed in 52 PAC eyes of 28 participants. The change of intraocular pressure and anterior segment parameters, including angle opening distance (AOD500), AOD500 area, trabecular iris space area (TISA500), TISA500 volume, trabecular iris angle (TIA500), iridotrabecular contact (ITC) index, ITC area, anterior chamber volume (ACV), anterior chamber depth (ACD), lens vault (LV) and lens thickness (LT) before and 1 week after LPI were measured by Tomey CASIA2 anterior segment OCT. We also estimate and analyze potential contributing factors possibly affecting the change of anterior chamber angle parameters. Results No post-laser complications were found. The LV and LT did not change significantly 1 week after LPI. AOD500, AOD500 area, TISA500, TISA500 volume, TIA500, ACV and ACD increased significantly after LPI. There was significant decrease in ITC index and ITC area. LT was positively correlated to the change of ITC index (r=0.411, p=0.002) and ITC area (r=0.384, p=0.005). ACD was negatively correlated to the change of ITC index (r=0.292, p=0.036). Conclusions The anterior segment architecture significantly changed after LPI in PAC spectrum eyes. Crystalline lens measurements remained unchanged before and after LPI. AS-OCT can be used to follow anterior chamber parameter changes in PAC spectrum eyes. Pre-treatment LT and ACD affect the therapeutic effect of LPI.

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sung-Cheol Yun ◽  
Ji Wook Hong ◽  
Kyung Rim Sung ◽  
Jin Young Lee

Purpose. To investigate the effect of laser peripheral iridotomy (LPI) in subgroups of primary angle closure based on iris insertion configuration.Methods. Anterior segment optical coherence tomography (AS-OCT) images were obtained before and two weeks after LPI. Qualitative classification of angle closure eyes according to iris insertion (basal insertion group (BG) and nonbasal insertion group (NBG)) was performed. Anterior chamber depth (ACD), lens vault (LV), iris curvature, iris area, iris thickness (IT750), and angle opening distance (AOD750) 750 microns from scleral spur were calculated. Uni- and multivariate regression analysis was carried out to evaluate factors associated with AOD750before and after LPI.Results. Ninety-two eyes of 92 subjects were categorized as NBG (39 eyes) or BG (53 eyes). The mean change after LPI was not significantly different between two groups in all parameters. In both groups, AOD750was affected by ACD (p<0.001,p=0.044) before LPI. AOD750was affected by LV (p=0.012) in NBG, but by ACD (p<0.001) and IT750(p=0.039) in BG after LPI.Conclusions. The outcomes of LPI are not significantly different between angle closure subgroups with different iris insertions. However, factors affecting AOD750show differences between two subgroups after LPI.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xinbo Gao ◽  
Yuying Zhou ◽  
Chengguo Zuo ◽  
Liming Chen ◽  
Jiawei Ren ◽  
...  

Aim: The aim of this study was to investigate the changes in anterior segment parameters as assessed by ultrasound biomicroscopy (UBM) after laser peripheral iridotomy (LPI) and to propose a prediction equation for the width of the angle after LPI.Design: This was a prospective study.Participants: The participants included 100 subjects with primary angle closure suspect (PACS).Methods: Anterior segment UBM parameters were measured, whereas AOD750 was chosen to indicate the width of the angle associated with gonioscopic angle closure, as found in a prior study.Main Outcome Measures: Angle parameters, iris parameters, anterior chamber parameters and ciliary body parameters.Results: All angle parameters increased after LPI, including the mean angle opening distance at 750 μm (AOD750), mean angle opening distance at 500 μm from the scleral spur (AOD500), mean angle opening distance at 750 μm from the scleral spur (AOD750), and mean angle recess area at 750 μm from the scleral spur (ARA750). Among iris parameters and ciliary body parameters, the iris thickness at 2,000 μm (IT2000), iris curvature (IC), and trabecular-ciliary process distance (ICPD) were reduced after LPI. The final equation consisted of four parameters: anterior chamber depth (ACD), iris thickness at 750 μm from the scleral spur (IT750), AOD750, and lens vault (LV). This equation explained 42.7% of the variability in the angle opening indicator AOD750 after LPI, whereas in the plateau iris configuration subgroup, the accuracy of the prediction equation reached the highest a maximum of 68.6%.Conclusions: There was an increase in angle opening and iris flattening after LPI. An equation involving four angle parameters was constructed, this equation which could explained 42.7% of the variability in the angle opening indicator AOD750 after LPI whereas in the plateau iris configuration subgroup, the accuracy of the prediction equation reached a maximum of 68.6%.


2016 ◽  
Vol 166 ◽  
pp. 133-140 ◽  
Author(s):  
Sasan Moghimi ◽  
Rebecca Chen ◽  
Mohammadkarim Johari ◽  
Faezeh Bijani ◽  
Massood Mohammadi ◽  
...  

2017 ◽  
Vol 8 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Hiroshi Sakai ◽  
Michiko Yonahara ◽  
Miyako Sakai

A 59-year-old woman was seen by an ophthalmologist for blurred vision, ocular pain, headache, and nausea. She was diagnosed with acute primary angle closure (APAC) and successfully treated with medications. Using ultrasound biomicroscopy (UBM), engorged episcleral vein was observed and small uveal effusion was diagnosed after laser peripheral iridotomy (LPI). The uveal effusion disappeared and was again diagnosed by UBM together with anterior segment inflammation with ocular pain. Iritis caused by LPI after APAC might be a cause of uveal effusion in this specific case.


2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Wakako Ikegawa ◽  
Takashi Suzuki ◽  
Koji Namiguchi ◽  
Shiro Mizoue ◽  
Atsushi Shiraishi ◽  
...  

Purpose. To quantify changes in anterior segment (AS) parameters after laser peripheral iridotomy (LPI) using AS-optical coherence tomography (OCT) of iris bombe. Method. AS images of eight eyes were captured before and after iris bombe and more than 2 weeks after LPI (post-LPI) using AS-OCT. We compared the following AS parameters: anterior chamber depth (ACD), anterior chamber volume (ACV), iris curvature (IC), iris thickness at 500 μm from the scleral spur (IT-1) in the middle between the iris root and pupillary margin (IT-2) and 500 μm from the pupillary margin (IT-3) to the anterior chamber angle (ACA) (angle opening distance [AOD750]), and trabecular iris space area. Results. Mean IT-1 and IT-3, but not IT-2, were lower after iris bombe (IT-1, P=0.001; IT-2, P=0.081; and IT-3, P=0.001). There were no significant differences between ACD at pre-LPI and before iris bombe (P=0.096). The mean ACV and AOD750 of iris bombe increased at post-LPI (ACV, P<0.01, and AOD750, P<0.05). The mean IT-1, IT-2, and IT-3 increased at post-LPI (all, P≤0.01). IC decreased at post-LPI (P<0.001), and ACD at post-LPI did not change. Conclusions. The iris extends and becomes thinner during iris bombe. LPI during bombe decreases the IC and increases the ACV and ACA.


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