Does an iridotomy provide protection against narrowing of the anterior chamber angle during Valsalva maneuvre in eyes with primary angle closure

PURPOSE: To evaluate changes at the anterior chamber angle during Valsalva manoeuver, in eyes having primary angle closure (PAC) and a patent laser peripheral iridotomy. METHODS: Twenty-three eyes of 23 consecutive patients underwent a recording of applanation tonometry, measurement of the anterior chamber angle recess, angle opening distance, iris thickness, anterior chamber depth, and pupil size on ultrasound biomicroscopy before and during the Valsalva maneuver. The Valsalva manoeuver was standardized to a pressure of 40 mmHg for 15 s, using a manometer.RESULTS:The mean baseline intraocular pressure changed from 18.86+3.79 to 26.73+4.73 mmHg during Valsalva, (P<0.0001). The anterior chamber angle recess narrowed from 16.62+6.24 to 6.5+4.02 degrees (P<0.0001). There was a significant increase in the thickness of the ciliary body from 0.92+0.25 to 1.17+0.31 mm (P=0.0006) and in the iris thickness from 0.47+0.17 to 0.57+0.11 mm (P=0.007). A significant increase in pupillary diameter (P=0.008) and a decrease in the angle opening distance (P<0.0001) also occurred during Valsalva, whereas there was no significant change in the anterior chamber depth (P=0.056). The angle recess during Valsalva had a positive correlation with the baseline anterior chamber angle (r=0.41, P=0.05) and a negative correlation with the ciliary body thickness (r=-0.52, P=0.046).CONCLUSIONS: The induction of Valsalva maneuver in day-to-day activities can lead to significant anterior segment angle shallowing and can lead to progression from the PAC stage to primary angle closure glaucoma in such predisposed eyes. The presence of a patent laser iridotomy may not prevent irido trabecular apposition during the Valsalva maneuver.     

Iridociliary apposition in plateau iris syndrome persists after cataract extraction

PURPOSE: To evaluate the ultrasound biomicroscopic appearance of the anterior segment before and after cataract extraction in eyes with plateau iris syndrome and to determine the effect of postoperative zonular relaxation on ciliary body position. DESIGN: Interventional case series. METHODS: Eyes with plateau iris syndrome scanned before and after cataract extraction between January 1994 and September 2001 were enrolled. The iridociliary relationship and the anterior chamber depth at a distance of 3 mm from the scleral spur were assessed. RESULTS: We examined six eyes of six patients. Mean patient age was 74.2 +/- 6.4 years (standard deviation [SD]) (range, 65-81 years). Mean refractive error was + 1.0 +/- 3.9 diopters [D] (range, -5.75-+5.50), and mean axial length was 21.85 +/- 0.77 mm (range, 20.90-22.95 mm). All eyes had undergone laser iridotomy and argon laser peripheral iridoplasty before cataract extraction. Ultrasound biomicroscopy examination revealed a narrow angle and absence of a ciliary body sulcus in all eyes with focal areas of iridotrabecular apposition in three eyes. Following cataract extraction, the anterior chamber depth increased (P =.0006, paired t test), while the iridociliary contact remained unchanged. CONCLUSIONS: Iridociliary apposition persists after cataract extraction in plateau iris syndrome. Whether the cause is congenital or acquired, or both, remains to be determined.     

急性原发性房角关闭对侧眼激光周边虹膜切除术后接触性房角关闭的研究

目的了解急性原发性房角关闭（APAC）对侧眼激光周边虹膜切除术（LPI）后接触性房角关闭的发生率和眼部解剖特征。方法前瞻性研究。选择54例APAC对侧眼没有虹膜前黏连（PAS）的患者作为研究对象,平均年龄（67．1±7．2）岁（54—83岁）。采用超声生物显微镜（UBM）在暗环境下观察LPI后是否发生接触性房角关闭．并比较发生接触性房角关闭与不发生接触性房角关闭患眼的眼压、房角及各项UBM参数,包括房角开放距离。（AOD跏）、房角隐窝面积,。（ARA750）、小梁虹膜夹角（T—I角）、小梁睫状体距离（TCPD）、周边虹膜厚度（IT1）、虹膜悬韧带距离（IZD）、虹膜根部附着位置、中央前房深度（ACD）。对两组数据采用独立样本t检验及两样本秩和检验进行分析。结果LPI后暗环境下UBM检查至少一个象限发生接触性房角关闭的有20例,占37％。反映房角开放程度的指标（AOD500、ARA750、T-I角）和反映睫状体位置的指标（TCPD）：接触性房角关闭（＋）组小于（-）组（t=11．741、11．089、12．175、4．349,P均〈0．01）;反映虹膜形态和位置的指标IT1：接触性房角关闭（＋）组大于（-）组（t=-3．300,P=0．002）;IZD、虹膜根部附着位置及ACD比较,两组差异无统计学意义（t=-1．880,P=0．066;Z=-1．423,P=0．155;t=0．072,P=0．942）。结论APAC对侧眼LPI后在暗环境下仍有一定比例发生接触性房角关闭,房角窄、睫状体前位、周边虹膜厚是LPI后发生接触性房角关闭的解剖学特点,提示LPI后具有这些解剖特点的APAC患者有可能进展为慢性房角关闭。     

Ultrasound biomicroscopy in the subtypes of primary angle closure glaucoma

PURPOSE: To evaluate the anterior segment parameters in the subtypes of primary angle closure glaucoma (PACG) using ultrasound biomicroscopy. METHODS: Five groups, each comprising 30 consecutive patients, diagnosed to have subacute PACG, acute PACG, chronic PACG, primary open angle glaucoma (POAG), and healthy controls were included in the present study. All patients underwent slit-lamp biomicroscopy, direct ophthalmoscopy, 90D fundus examination, gonioscopy, applanation tonometry, visual field testing, A-scan biometry, and ultrasound biomicroscopy (UBM). The anterior segment parameters recorded included: trabecular-iris angle, angle opening distance, trabecular ciliary process distance, and the iris thickness among other parameters. RESULTS: On ultrasound biomicroscopy the trabecular iris angle of control and POAG groups was more than all the subtypes of PACG (P < 0.001). The trabecular iris angle of subacute PACG (P < 0.001) and chronic PACG (P = 0.003) was more than acute PACG. Angle opening distance of controls and POAG group was significantly more than acute PACG and chronic PACG (P < 0.001). The trabecular ciliary process distance of POAG group and controls was more than subacute PACG, acute PACG, and chronic PACG. The trabecular ciliary process distance of subacute PACG (P < 0.001) and chronic PACG (P < 0.001) was more than acute PACG. Eyes with acute PACG had the least iris thickness at the three different positions tested. There was a positive correlation between the anterior chamber angle (trabecular iris angle) and the following parameters: trabecular ciliary process distance, angle opening distance, anterior chamber depth, and the axial length (r = 0.57). CONCLUSION: Eyes with primary angle closure glaucoma have a thinner iris with a shorter trabecular iris angle, angle opening distance, and trabecular ciliary process distance. The eyes with acute primary angle closure glaucoma have the narrowest angle recess.     

Ultrasound biomicroscopic findings in aniridia

PURPOSE: To describe the ultrasound biomicroscopic features of eyes with aniridia. DESIGN: Observational case series. METHODS: Nineteen eyes of 10 patients with aniridia (six males and four females) ranging in age from 3 months to 53 years (21.0 +/- 16.4, mean +/- SD), and 50 normal subjects (30 men and 20 women) ranging from 16 to 56 years (31.1 +/- 13.2) were evaluated. Ultrasound biomicroscopic findings were recorded in the 3-, 6-, 9-, and 12-o'clock directions. Adult patients (aged 16 years or older) with aniridia were compared with the age-matched controls. RESULTS: Ultrasound biomicroscopy (UBM) detected extremely tiny irises in all eyes with aniridia. The eyes with aniridia showed significantly smaller values than the controls in ciliary body length (4.49 +/- 0.63 versus 5.79 +/- 0.44 mm, P <.001, unpaired Student t test), ciliary body thickness (0.75 +/- 0.17 versus 1.24 +/- 0.22 mm, P <.001), iris root thickness (0.47 +/- 0.14 versus 0.61 +/- 0.07 mm, P <.001), scleral-ciliary process angle (31.7 +/- 3.26 versus 43.1 +/- 4.48 degree, P <.001), and anterior chamber depth (1.99 +/- 0.43 versus 2.94 +/- 0.34 mm, P <.001). In the aniridia eyes, there was a significantly positive correlation between iris thickness and ciliary body thickness (Pearson r = 0.829, P =.001). CONCLUSION: Ultrasound biomicroscopic imaging demonstrated that not only iris hypoplasia but also ciliary body hypoplasia exist in aniridia. Anterior inclination of the ciliary process was also found, which was thought to be at least partly responsible for the shallow anterior chamber.     

原发性闭角型青光眼患者与可疑原发性房角关闭患者虹膜睫状体构型特征的比较分析

目的 比较原发性闭角型青光眼（PACG）患者与可疑原发性房角关闭（PACS）患者的房角生物学特征。设计 回顾性比较性病例系列。研究对象 2019年10月至2021年3月同济医院58例PACG及PACS患者。方法 回顾患者病例资料及超声生物显微镜（UBM）图像,测量其房角生物学参数,进行定量及定性分析。主要指标 中央前房深度（ACD）、500 μm房角开放距离（AOD500）、500 μm小梁虹膜夹角（TIA500）、500 μm小梁睫状突距离（TCPD500）、500 μm小梁睫状体夹角（TCA500）、虹膜根部厚度（IT500）、睫状突长度（CPL）、睫状体厚度（CBT）。结果 与PACS组（n=25）相比,PACG组（n=33）患者最佳矫正视力（BCVA）更低（0.4±0.35、0.2±0.17）,基线眼压更高（21.17±6.09、15.57±3.57 mmHg）,眼轴更短（22.17±1.22、22.74±0.88 mm）,ACD更浅（1.77±0.27、1.94±0.25 mm）,AOD500、TIA500、TCPD500、TCA500更小（0.04±0.04、0.10±0.05 mm;3.90±4.58、11.07±4.77°;0.51±0.10、0.58±0.10 mm;60.55±13.26、71.54±12.58°）,CPL更长（1.43±0.26、1.28±0.15 mm）。虹膜插入点位于睫状体基底部的比例（54.5%、20.0%）及睫状体前旋的比例（68.0%、39.4%）PACG组较PACS组更大（P均<0.05）。而IT500、CBT、虹膜成角和虹膜凸度在两组间未见差异。结论 PACG眼较PACS眼具有更短的眼轴和更浅的前房,长而前旋的睫状体构型更明显,虹膜插入点位于基底部的比例更高。（眼科,2022,31： 20-26）     

环扎加压术后眼前节改变的初步观察

目的 观察环扎加压术后患眼眼前节的结构改变,探讨这些变化对预后的影响。方法 应用超声生物显微镜检测２５名非复杂性视网膜脱离患者手术前后眼前节的改变,观察是否有脉络膜脱离,并进行定量测定,结果行配对ｔ检验。结果 术前９只眼（３６％）有睫状脱离,以裂隙状主。术后２１只眼（８４％）发生睫状体脱率,以楔状为主,并伴有睫状体水肿,水肿的程度与脱离的宽度密切相关（ｒ＝０．７１３,Ｐ〈０．０５）。定量测定表明：房角开放距离、小梁／虹膜平角、睫状体厚度、睫状体脱离的宽度均有显著性差异（Ｐ〈０．０１）。而前房中央深度无显著改变（Ｐ〉０．０５）。结论 睫状体脱离,睫状体水肿,前房角狭窄是环扎加压术后的普遍现象。房角狭窄是继发青光眼的潜在危险因素。     

Comparison of ultrasound biomicroscopic parameters after laser iridotomy in eyes with primary angle closure and primary angle closure glaucoma

PURPOSE: To study changes in anterior segment morphology after laser peripheral iridotomy (LPI) in primary angle closure (PAC) and primary angle closure glaucoma (PACG) using ultrasound biomicroscopy (UBM). METHODS: Ninety-three eyes of 93 patients underwent anterior segment evaluation including gonioscopy, disc evaluation with + 90D lens, applanation intraocular pressure, and standard achromatic perimetry. UBM was performed before and 2 weeks after Nd:YAG LPI to measure the trabecular-iris angle (TIA), the angle-opening distance (AOD 250/500), and the central anterior chamber depth (ACD). RESULTS: The superior TIA widened from a mean of 7.54+/-3.15 to 15.66+/-6.69 degrees (P=0.0001), the inferior TIA increased from a mean of 9.0+/-4.7 to 15.9+/-6.8 degrees (P=0.0001) after LPI in PAC. In PACG, the mean superior angle changed from 4.55+/-2.5 to 6.12+/-3.8 degrees (P=0.4) and the inferior angle increased from 4.75+/-2.0 to 7.9+/-3.7 degrees (P=0.1). The mean ACD increased from 2.19+/-0.36 to 2.30+/-0.36 mm in PAC group (P=0.0003), with no significant change seen in the PACG group (1.79+/-0.32 vs 1.82+/-0.33 mm, P=0.13). CONCLUSION: LPI leads to a widening of the anterior chamber angle and a deepening of the anterior chamber in eyes with PAC. It does not significantly change any anterior segment parameters in eyes with PACG.     

原发性房角关闭眼激光虹膜切除术后UBM测量参数比较

目的:比较激光虹膜切开术前后原发性房角关闭(primary angle closure,PAC)眼超声生物显微镜(ultrasound biomicroscopy,UBM)参数。方法:对46例74眼PAC患者进行了一项前瞻性临床试验。平均年龄58,04±11.33(24.0-82.0)岁。所有病例行完整的眼科检查,前房角镜A超生物测量和超声生物显微镜检查(Vu-max,SonomedInc.,NY,USA)及24-2标准无色差视野检查(SAP,Humphrey Visual Field Analyzer-II i,Carl Zeiss Meditec Inc.,Dublin,CA,USA)。使用配对t检验评估基准和随访的平均值之间的变化。结果:激光周边虹膜切除术(laser peripheral iridotomy,LPI)术后,平均房角从8.02±4.61(0.10-19.60)度增加到17.66±6.39(0.10-32.70)度(P=0.000),房角开放距离500(angle opening distance 500,AOD500)从0.11±0.06(0.01-0.30)mm增加到0.23±0.07(0.13-0.50)mm(P=0.000),平均虹膜厚度(iris thickness,IT)从0.58±0.11(0.33-0.99)mm下降到0.52±0.10(0.25-0.77)mm(P=0.000)。小梁睫状突距离,虹膜睫状突距离和睫状体厚度均未发现显著统计学差异。结论:LPI术后PAC的白种人眼睛的AOD500,虹膜晶体距离和前房角增加,IT和虹膜晶体高度减少。这说明LPI解除了瞳孔阻滞,加深了前房,扩大了房角,减少了虹膜前凸和增厚。     

应用超声生物显微镜研究睫状肌麻痹剂对眼前节结构的影响

目的应用超声生物显微镜观察局部应用睫状肌麻痹剂前、后眼前节形态结构的改变及其与眼压的关系,同时对睫状体厚度、睫状体晶体赤道部距离进行观察。方法以４８只正常眼为研究对象,在局部应用２％后马托品前、后分别进行眼前节结构的超声生物显微镜定量测定,并测量眼压。对其结果进行统计学分析。结果用药后在反映房角改变的参数中,小梁虹膜夹角减小,房角开放距离２５０减小,虹膜厚度１增厚,前房加深,虹膜晶体接触距离缩短,差异均有显著性（Ｐ＜０．０５）;在反映睫状体改变的参数中,睫状体和睫状突的厚度减小,巩膜睫状体夹角增大,虹膜悬韧带距离减小,睫状体晶体距离增大,差异有显著性（Ｐ＜０．０５）。应用睫状肌麻痹剂后,眼压由２．３５±０．４６ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）升高至２．４３±０．４７ｋＰａ,但差异无显著性（Ｐ＞０．０５）。结论局部应用睫状肌麻痹剂后,前房加深、房角变窄、睫状体变薄且向后运动、睫状体晶体距离增大。超声生物显微镜能动态观察眼前节结构的改变并行定量测定,在眼前节形态学研究中具有优越性。     

Ultrasound biomicroscopic study of ciliary body thickness in eyes with narrow angles

PURPOSE:To determine the ciliary body thickness and other biometric findings in eyes with narrow angles.METHODS:Eighteen otherwise normal eyes with narrow angles in 18 Japanese patients and 18 normal control eyes with open angles in 18 age-matched and sex-matched Japanese patients were studied. A-scan ultrasonography was performed to measure anterior chamber depth, lens thickness, axial length, and relative lens position. Ultrasound biomicroscopy was also performed to obtain measurements of the anterior ocular structures, including anterior chamber depth and ciliary body thickness at sites 1 mm and 2 mm posterior to the scleral spur (positions 1 and 2, respectively). RESULTS:Compared with normal control eyes, the narrow-angle eyes showed a shallower anterior chamber (narrow angle, 1.87 +/- 0.27 mm; control, 2.69 +/- 0.26 mm; P <.0001), a thicker lens (4.97 +/- 0.49 mm, 4.26 +/- 0.53 mm; P <.0001), a more anteriorly located lens (2. 21 +/- 0.13, 2.35 +/- 0.14; P <.0001), a shorter axial length (22.70 +/- 0.97 mm, 23.41 +/- 0.86 mm; P =.012), and a thinner ciliary body (position 1: 454 +/- 107 microm, 602 +/- 86 microm; P <.0001; position 2: 203 +/- 50 microm, 321 +/- 68 microm; P <.0001). Lens thickness was significantly correlated with ciliary body thickness at positions 1 (R(2) = 0.34; P =.0001) and 2 (R(2) = 0.43; P <.0001). Anterior chamber depth was significantly correlated with ciliary body thickness at positions 1 (R(2) = 0.48; P <.0001) and 2 (R(2) = 0.56; P <.0001).CONCLUSION:Thinning of the ciliary body may be one of the important factors associated with the anterior location of the lens, the increased lens thickness, and the decreased anterior chamber depth in eyes with a narrow angle.     

Ultrasound biomicroscopic characteristics of the anterior segment in primary congenital glaucoma

PURPOSE: To evaluate qualitatively and quantitatively ultrasound biomicroscopic (UBM) features of the anterior segment in eyes with primary congenital glaucoma. METHODS: UBM of 45 eyes of patients with primary congenital glaucoma (39 previously operated and 6 unoperated eyes) and 28 control eyes were included in this study. UBM parameters were correlated with ocular biometry. Iris thickness, ciliary body thickness, ciliary body-lens distance, posterior chamber depth, and anterior chamber angle were measured and compared with control eyes. Other features of the anterior segment were qualitatively evaluated. RESULTS: A thin, stretched-out ciliary body and abnormal tissue at the iridocorneal angle were features seen in 90% of UBM scans. Iris thickness and stretched zonules correlated with the axial length (r = -0.6 and 0.58, respectively; p = 0.04) but not with the mean corneal diameter. Abnormal insertion of the ciliary body to the posterior surface of the iris was noted in eight eyes (17%). CONCLUSIONS: The present study documents characteristic anterior segment dysplasia and ciliary body anomalies in patients with primary congenital glaucoma.     

Peripheral anterior synechiae and ultrasound biomicroscopic parameters in angle-closure glaucoma suspects

PURPOSE: To investigate the correlation between peripheral anterior synechia (PAS) and the quantitative anterior chamber angle parameters measured by ultrasound microscopy (UBM) in angle-closure glaucoma suspect (ACGS) eyes. METHODS: Eyes were defined ACGS as having occludable angles and intraocular pressure less than 21 mm Hg without glaucomatous optic nerve head. The gonioscopic criteria for ACGS were the trabecular meshwork invisible in 3 or more quadrants of the entire angle and the angular width less than 20 degrees by Shaffer classification. Twenty-seven eyes of 20 patients underwent anterior chamber angle and ciliary body imaging with UBM. Angle opening distance (AOD(500)), angle recess area (ARA), trabecular-ciliary process distance (TCPD) and trabecular-iris angle (TIA) were measured from the UBM images at each quadrant. RESULTS: The AOD(500), ARA, and TIA were not significantly different between the eyes with PAS (9 eyes) and without PAS (18 eyes) at each quadrant. However, the TCPD was significantly shorter in the superior quadrant when compared with the eyes without PAS (mean: 405.3+/-70.9 microm vs 536.4+/-140.5 microm) (p<0.05). CONCLUSIONS: The results suggest that the shorter distance from trabecular meshwork to ciliary body or the anterior placement of ciliary process may play a role in the development of PAS in ACGS eyes.     

全景超声生物显微镜对人眼睫状沟距离及前房直径的测量

背景睫状沟距离的直接测量对人工晶状体（IOL）植人术中IOL尺寸的选择具有重要意义。全景超声生物显微镜（UBM）的问世使在活体眼直接进行睫状沟距离的测量成为可能。目的探讨人眼前房直径和睫状沟距离之间的相关性及其在不同前房深度人群中的差别。方法将疑似青光眼患者30例30只右眼作为浅前房组,而具有高度近视（-7— -18D）的30例30只右眼作为深前房组。应用全景超声生物显微镜（UBM）进行图像采集,每眼获取焦点位于虹膜平面的眼球水平方向3：00～9：00处的全景截面图像共3张。由同一测量者对每一幅图像的前房直径和睫状沟距离进行测量。取3幅图像测量值的均值为最终测量结果,用独立样本t检验和线性回归方程分析评估前房直径与睫状沟距离测量值的关系。结果浅前房组的30眼中,全景UBM测得的前房直径为（11．49±0．75）mm,睫状沟距离为（10．97±0．86）mm,二者间的平均差值为（-5．14±0．55）mm,差异有统计学意义（t=-5．092,P=0．000）,线性回归分析显示二者之间呈线性相关（R2=0．593,P=0．000）,Pearson相关系数为0．767。深前房组的30眼中,全景UBM测得的前房直径均值为（12．69±0．67）mm;睫状沟距离为（12．31±0．61）mm,二者之间平均差值为（-0．38±0．17）mm,差异有统计学意义（t=-5．531,P=0．000）;线性回归分析显示二者之间具有显著相关性（R2=0．699,P=0．000）,Pearson相关系数为0．836。结论全景UBM测得的睫状沟距离和前房直径呈明显正相关,深前房眼的相关性大于浅前房眼,该结果对于IOL植入术中IOL尺寸的选择具有重要意义。     

OCT-Goniometrie vor und nach Iridotomie beim Engwinkelglaukom

PURPOSE: Visualization of the anterior chamber angle is an important diagnostic method in patients with angle-closure glaucoma. In this study, optical coherence tomography (OCT) was used to image the angle width, the iris configuration, and the iris thickness in patients with angle-closure glaucoma. METHODS: Thirteen eyes of 11 patients suffering from angle-closure glaucoma were studied with slitlamp-adapted OCT. All patients were treated with Nd:YAG laser iridotomy. The angle width ( degrees ), the angle opening distance (AOD) (microm), and the iris thickness (microm) were measured with OCT. The configuration of the iris was classified as steeply convex, convex, or flat. RESULTS: The mean angle width was preoperatively 5.1+/-5.0 degrees (0-15 degrees ) and enlarged significantly (p=0.007) to 10.4+/-5.5 degrees (0-19 degrees ) postoperatively. The AOD changed from 71+/-55 microm (0-157 microm) preoperatively to 143+/-74 microm (0-256 microm) postoperatively (p<0.001). The mean iris thickness was 338+/-33 microm. With the exception of two eyes the predominant iris configuration changed from convex to flat. CONCLUSIONS: OCT allowed visualization and noninvasive assessment of the anterior chamber angle region in patients with angle-closure glaucoma. Our results suggest that goniometry with OCT could improve the evaluation in patients with narrow or closed anterior chamber angles.     

小剂量激光睫状体成形术治疗急性闭角型青光眼的试点研究

目的 观察小剂量激光睫状体成形术（low dose trans-scleral cycloplasty,LDCP）治疗急性闭角型青光眼后前房深度和房角参数的变化。设计 前瞻性病例系列。研究对象 2018年5月至 2019年11月温州医科大学附属眼视光医院急性闭角型青光眼急性大发作患者12例15眼,年龄（54.7±14.1）岁。方法 LDCP是采用较少激光点数（能量1200~2000 mw,持续时间2 s）、仅对2个钟点范围睫状体光凝而达到睫状体重塑、松解睫状环阻滞的一种方法。分析治疗前和治疗后1周、1个月、3个月的临床资料。主要指标 眼压、中央前房深度、房角开放距离500 （angle opening distance 500,AOD500）、小梁网-虹膜夹角500 （trabecular iris angle 500,TIA500）、最大睫状突厚度（CBTmax）、小梁睫状突夹角（TCA）、降眼压药物使用情况。结果 15眼平均激光治疗点数为（13.3±2.3）（9~16个点）。治疗前眼压中位数（范围）为26.6（7.3~60.0） mmHg,治疗后1周为10.6（6.1~53.9） mmHg（Z=-2.726,P=0.006）。治疗前抗青光眼药数量中位数（范围）为3 （0~5）种,治疗后1周为0 （0~3）种 （Z=-3.078,P=0.002）。超声生物显微镜（ultrasound biomicroscopy,UBM）显示平均中央前房深度、AOD500和TIA500分别由治疗前的（1.44±0.48）mm、0.00（0~0.19） mm、0.00（0~20.1）°,增加至治疗后1周的（1.66±0.34）mm、0.04（0~0.28）mm、4.63（0~28. 5）°  （P均<0.05）;平均CBTmax和TCA分别由治疗前的（0.98±0.12）mm和（55.7±16.8）°,增加至治疗后1周的（1.05±0.09）mm和 （66.8±17.3）° （P=0.060,0.004）;13眼（86.7%）周边前房深度（Van Herick法）较治疗前有不同程度的增加。8眼在治疗后1个月内因不同原因行白内障手术,未行二次手术治疗的7眼治疗后3个月的中位数眼压和平均前房深度分别为15.5 mmHg和1.73 mm。结论 LDCP可明显加深急性闭角型青光眼的中央和周边前房,具有良好的即时降眼压效应,为闭角型青光眼急性期的治疗提供了一种新思路,但该治疗的安全性有待进一步观察。（眼科,2021,30： 30-35）     

Ultrasound biomicroscopy dark room provocative testing: a quantitative method for estimating anterior chamber angle width

PURPOSE: To describe a quantitative method for measuring the iridocorneal angle recess area, and, using this, to evaluate factors associated with appositional angle-closure during dark room provocative testing using ultrasound biomicroscopy (UBM). METHODS: All patients (178 patients, 178 eyes) with clinically narrow angles referred for UBM dark room provocative testing between September 1996 and March 1998 were enrolled in this study. Images of the inferior quadrant of the angle taken under standardized dark and light conditions were analyzed. The angle recess area (ARA) was defined as the triangular area demarcated by the anterior iris surface, corneal endothelium, and a line perpendicular to the corneal endothelium drawn from a point 750 microm anterior to the scleral spur to the iris surface. ARA, and acceleration and gamma-intercept of the linear regression analysis of the ARA were calculated. In the linear regression formula, y = ax + b, the acceleration a describes the rate at which the angle widens from the scleral spur; the y-intercept b describes the distance from the scleral spur to the iris. RESULTS: Under dark conditions, the angles in 99 patients (55.6%) showed evidence of appositional angle-closure during testing. ARA (0.11 +/- 0.04 vs. 0.15 +/- 0.05 mm2, P < .0001, Student t-test), acceleration a (0.22 +/- 0.15 vs. 0.26 +/- 0.17, P = .068), and y-intercept b (66 +/- 46 vs. 92 +/- 47 microm, P = .0003) were smaller in eyes that were occluded. In the eyes that were not occluded, y-intercept b showed no significant difference between light and dark conditions (P = .1, paired t-test), while acceleration a did (P < .0001). In the eyes that were occluded, both decreased significantly under dark conditions (P < .0001). CONCLUSIONS The ARA linear regression formula provides useful quantitative information about angle recess anatomy. The more posterior the iris insertion on the ciliary face, the less likely the provocative test will be positive.     

Ultrasound biomicroscopic changes during accommodation in eyes with accommodating intraocular lenses: pilot study and hypothesis for the mechanism of accommodation

PURPOSE: To document ciliary body constriction and movement with the Crystalens AT-45 intraocular lens (IOL) (eyeonics) using ultrasound biomicroscopy. SETTING: Eye Clinic, Department of Neurological and Visual Sciences, University of Verona, Verona, Italy. METHODS: Patients with no preexisting ocular conditions other than cataract who agreed to return for follow-up were considered. Twenty eyes of 14 patients with a best corrected visual acuity of 5/10 or worse and a refractive error (spherical equivalent) of +/-1.0 diopter (D) had implantation of a Crystalens AT-45 accommodating IOL. Six patients had bilateral implantation. Ultrasound biomicroscopy was performed postoperatively at 1 and 6 months. Before and during accommodation, the anterior chamber depth (ACD) was measured to assess the endothelium-IOL distance and measure the scleral-ciliary process angle to determine whether there was anterior rotation of the ciliary body. The uncorrected distance acuity, best corrected distance acuity, uncorrected near acuity, distance corrected near acuity, best corrected near acuity, and accommodative amplitude were determined. Analysis was done to determine whether there was a correlation between the accommodative amplitude and the percentage variation in the ACD and scleral-ciliary process angle. RESULTS: All surgical procedures were uneventful. The mean uncorrected distance acuity at 1 month was 0.8 +/- 0.14 (SD) and remained stable at 6 months. Three of 20 eyes (15%) and 8 of 20 eyes (40%) had a Jaeger acuity of J1 and J3, respectively, without additional power correction. During accommodation, the mean reduction in ACD was 0.32 +/- 0.16 mm at 1 month and 0.33 +/- 0.25 mm at 6 months. The mean narrowing of the scleral-ciliary process angle was 4.32 +/- 1.87 degrees at 1 month and 4.43 +/- 1.85 degrees at 6 months. There was a correlation between accommodative amplitude and a decrease in the ACD (r=0.404) and a decrease in scleral-ciliary process angle (r=0.773). CONCLUSIONS: Anterior displacement of the Crystalens IOL and corresponding anterior rotation of the ciliary body occurred during near vision. The IOL displacement and rotation were proportional to the accommodation capacity.     

Assessment of anterior chamber angle changes after phacoemulsification with swept-source OCT

AIM: To assess the changes of anterior chamber angle in patients with shallow anterior chamber after phacoemulsification combined with intraocular lens (IOL) implantation, based on anterior segment swept-source optical coherence tomography (AS-SS-OCT) measurements. METHODS: This was a prospective case control study; sixty eyes of sixty case were scheduled for cataract surgery with normal intraocular pressure (IOP). Based on anterior chamber depth (ACD) and gonioscopy findings, the eyes were divided into two groups: group of shallow anterior chamber and narrow angle (SAC group, 30 eyes); and group of normal anterior chamber group with wide angle (NAC group, 30 eyes). Measurements of ACD, anterior chamber volume (ACV), iris volume (IV), lens vault (LV), angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) were conducted in each group before and 3mo after surgery. RESULTS: There was no significant difference in age, axial length (AL), corneal curvature, corneal diameter, intraocular pressure, and IV between two groups before surgery, except for the LV (P=0.000). ACD and ACV were prominently larger in the NAC group than the SAC group 3mo after operation (3.69±0.38 vs 3.85±0.39 mm, P=0.025; 161.37±19.47 vs 178.26±20.30 mm3, P=0.002). AOD750, ARA750 in nasal and inferior quadrants, TISA750 in all quadrants except temporal, and TIA750 in all quadrants in SAC group were significantly smaller than those in NAC group after operation (all P<0.05). CONCLUSION: Cataract surgery can deepen anterior chamber and increase the width of anterior chamber angle in Chinese subjects, but the angle related parameters including AOD750, ARA750, TISA750, TIA, TISA750, and ACV in patients with shallow anterior chamber and narrow angle do not reach the normal level.     

Ultrasound biomicroscopic measurement of development of anterior chamber angle

AIM: To establish normative values for the anterior segment in normal infants and children in relation to age. METHODS: Anterior segments were measured in 46 normal infants and children (21 males and 25 females, aged from 1 to 60 months (mean 17.09 (SD 16.99) months)), by use of ultrasound biomicroscopy. RESULTS: Anterior chamber depth, trabecular-iris angle, angle opening (trabecular-iris) distances at 250 and 500 microm from the scleral spur, and the thickness of the thickest part of the iris were 1724-3473 microm (2505 (SD 480) microm), 15.35-44.79 degrees (28.74 (7.46) degrees ), 116-367 microm (247.4 (65.9) microm), 166-509 microm (349.5 (87.1) microm), and 249-579 microm (434.6 (74.6) microm), respectively. All factors in this study showed a significant correlation with logarithm of age (r = 0.937, p = 0. 0001; r = 0.867, p = 0.0001; r = 0.929, p = 0.0001; r = 0.917, p = 0. 0001; r = 0.748, p = 0.0001), and significantly correlated with each other. CONCLUSIONS: Ultrasound biomicroscopy is a powerful tool for obtaining precise images and measurement of the development of the anterior segment in infants and children. Normative values were established for anterior segment dimensions in relation to age. Anterior chamber depth, trabecular-iris angle, angle opening distances at 250 and 500 microm from the scleral spur, and iris thickness showed linear increases in relation to logarithm of age.