Narrowing of the anterior chamber angle during Valsalva maneuver: a possible mechanism for angle closure

PURPOSE: To evaluate changes at the anterior chamber angle during Valsalva maneuver in eyes suspected to have a primary adult glaucoma. METHODS: Seventy-six consecutive patients underwent recording of applanation tonometry, measurement of the anterior chamber angle recess, angle opening distance, angle recess area, scleral spur-iris root distance, iris thickness, iridociliary angle, ciliary body thickness, anterior chamber depth, and pupil size on ultrasound biomicroscopy before and during the Valsalva maneuver. The Valsalva maneuver was standardized to a pressure of 40 mmHg for 15 seconds, using a manometer. RESULTS: The mean baseline intraocular pressure changed from 19.5+/-4.1 mmHg to 29.5+/-4.8 mmHg during Valsalva (p<0.0001). The anterior chamber angle recess narrowed from 17.9+/-9.5 to 7.8+/-9.2 degrees (p=0.0001). The angle recess area diminished from 0.15+/-0.14 mm2 to 0.14+/-0.12 mm2 (p=0.03) and the scleral spur to iris distance decreased from 0.19+/-0.2 mm to 0.16+/-0.18 mm (p=0.0001). The iridociliary angle narrowed from 72.6+/-33.5 degrees to 62.5+/-32.8 degrees (p=0.04). There was a significant increase in the thickness of the ciliary body, from 0.99+/-0.19 mm to 1.12+/-0.16 mm (p=0.001) and in iris thickness from 0.47+/-0.07 mm to 0.55+/-0.09 mm (p=0.0001). There was no significant change in the angle opening distance, anterior chamber depth, or pupillary diameter. A significant narrowing of the angle to less than 5 degrees was seen in 37 eyes, with iridocorneal apposition present in 28 eyes. After multivariate regression analysis it was found that the baseline ciliary body thickness and angle recess were significant predictors of narrowing of the angle (R2=96.1%). CONCLUSIONS: Significant elevation of the intraocular pressure, narrowing of the anterior chamber angle recess, thickening of the ciliary body, and increase in the iris thickness is seen during the Valsalva maneuver. The Valsalva maneuver may lead to angle closure in eyes anatomically predisposed to primary angle closure glaucoma.     

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。     

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。     

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.     

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.     

The effect of laser iridotomy on the anterior segment anatomy of patients with plateau iris configuration

PURPOSE: To determine if laser iridotomy altered the anterior segment anatomy of patients with plateau iris configuration. METHODS: Twenty eyes of 9 female and 1 male patients were imaged using an ultrasound biomicroscope within 19 weeks before and 52 weeks after laser iridotomy. Measurements obtained included the anterior chamber depth (ACD), trabecular-ciliary process distance (TCPD), iris thickness (IT), angle opening distance at 500 micrometers (AOD), iridozonular distance (IZD), and trabecular-iris angle (TIA). Comparisons of the pre- and post- iridotomy measurements were made using a two-tailed paired t test. RESULTS: Laser iridotomy elicited no statistically significant change in ACD, TCPD, IT, AOD, or TIA. However, IZD was decreased (P < 0.05) in both eyes after laser iridotomy. Configuration of the irides was flat before and after laser iridotomies. CONCLUSION: This study suggests that laser iridotomy did not alter anterior segment anatomy, probably because of the fixed anterior insertion of the iris and ciliary body in plateau iris configuration. The decrease in IZD distance may be the result of a small posterior movement of the iris due to a reduction in relative pupillary block, secondary to laser iridotomy. The small reduction in relative papillary block in plateau iris configuration does not alter the width of the anterior chamber angle as measured by AOD and TIA.     

房角关闭机制指导下可疑原发性房角关闭患者激光干预的疗效评价

目的 根据房角关闭的不同机制,对可疑原发性房角关闭（PACS）患者行激光周边虹膜切除（LPI）术或LPI联合激光周边虹膜成形（LPIP）术,通过超声生物显微镜（UBM）评估PACS患者激光早期干预的疗效。设计 前瞻性病例系列。 研究对象2016年1月-11月在河北省邯郸市眼科医院连续就诊的PACS患者50例（65眼）。方法 根据房角关闭的不同机制,通过UBM评估患眼,对所有入选患眼均首先行LPI治疗,术后第3天复查UBM,检查提示仍存在至少一个象限房角呈接触性关闭的患者再进一步联合LPIP治疗。术后3天复查UBM,根据测量的相关参数的前后变化评价治疗效果。主要指标 UBM图像中的中央前房深度（ACD）,巩膜突前500 μm处的房角开放距离（AOD）、小梁虹膜夹角（TIA）、房角隐窝面积（ARA）、小梁睫状体距离（TCPD）、虹膜厚度（IT）。结果 65眼中,47眼（72.3%）行LPI治疗后3天UBM检查未发现存在至少一个象限的房角接触性关闭,术后AOD、TIA、TCPD、ARA较术前均明显增加（P均<0.01）,IT较术前无明显变化（P=0.465）;18眼（27.7%）行LPI术后3天,UBM提示存在至少一个象限的房角接触性关闭,联合LPIP治疗后AOD、TIA、TCPD、ARA较术前均明显增加（P均<0.01）,IT较LPI术后减少更明显（P<0.01）。结论 LPI后UBM可用于判断房角关闭的机制,并据此考虑是否联合LPIP,可进一步改善非单纯性瞳孔阻滞机制的可疑房角关闭患者的疗效。     

Ultrasound biomicroscopic imaging demonstrate thinner ciliary body thickness in eyes with angle closure

AIM: To compare the ciliary body thickness between eyes with primary angle closure (PAC) and primary angle-closure glaucoma (PACG) with the normal eyes, and to investigate the association between ciliary body thickness and ciliary processes situation. METHODS: In this cross-sectional study, 57 patients with PAC/PACG were matched to 57 normal subjects after propensity score matching (PSM) adjusting for age and gender. All subjects underwent conventional ocular examinations and ultrasound biomicroscopy (UBM) examination, among which the patients with PAC/PACG performed the examinations one month after laser peripheral iridotomy (LPI). Quantitative parameters were measured, which included ciliary body thickness at the position of 1 mm posterior to the scleral spur (CBT1), trabecular-ciliary process distance (TCPD) and trabecular-ciliary process angle (TCA). RESULTS: Eyes with PAC/PACG presented significantly thinner CBT1, shorter TCPD and smaller TCA (P<0.001) than the normal eyes, both in comparison of the means of four quadrants and in comparisons of each quadrant. After removing images with peripheral anterior synechia (PAS), the same results were also found in comparisons between the two groups. Significant correlations were found between TCPD (R2=0.537, P<0.001) and TCA (R2=0.517, P<0.001) with CBT1. CONCLUSION: Eyes with PAC/PACG have thinner ciliary body thickness and more anteriorly situated ciliary processes. Thinner ciliary body thickness is associated with anterior situation of the ciliary processes.     

Histological study on transient ocular hypertension after laser iridotomy in rabbits

We performed argon-laser iridotomy on pigmented rabbits and examined histologically the tissue of the anterior chamber angle, the iris, and the ciliary body. After laser iridotomy, 9/10 eyes showed an elevation in transient intraocular pressure. Deposits of blood plasma with fibrin were observed in the tissue of the circumferential anterior chamber angle from eyes enucleated at a period of high intraocular pressure. In the eyes in which ocular pressures returned to the baseline, the quantity of blood plasma was small. In the laser-irradiated iris and iris processes, cells constructing the vessel wall were degenerated, and blood plasma and fibrin exuded. In and around the ciliary body, fibrin was not demonstrated. These observations suggest that argon-laser irradiation to the iris leads to a breakdown of the blood-aqueous barrier mainly in the laser-treated iris, and that deposition of blood plasma with fibrin in the anterior chamber angle tissue may cause transient intraocular pressure elevations after laser iridotomy in rabbits.     

A prospective ultrasound biomicroscopy evaluation of changes in anterior segment morphology after laser iridotomy in Asian eyes

PURPOSE: To prospectively quantify changes in anterior segment morphology after laser iridotomy using gonioscopy and ultrasound biomicroscopy (UBM). DESIGN: Prospective comparative observational case series. PARTICIPANTS: Fifty-five fellow eyes of patients presenting with acute primary angle closure (APAC). METHODS: The fellow eyes of patients presenting with APAC were examined with UBM, A-scan ultrasonography, and optical pachymetry at presentation and 2 weeks after sequential argon/neodymium yttrium-aluminum-garnet laser peripheral iridotomy (LPI). UBM images were analyzed using UBM Pro 2000 software. Baseline measurements were made both under standard lighting conditions and in darkness to look for changes in anterior segment findings. MAIN OUTCOME MEASURES: The degree of angle opening was measured using the angle-opening distance (AOD) at 250 and 500 microm from the scleral spur (AOD250 and AOD500, respectively) and angle recess area (ARA). RESULTS: Fifty-five Asian patients were examined; AOD250, AOD500, and ARA all significantly increased after sequential laser iridotomy (P < 0.002). Gonioscopic grading of the angle opening significantly increased in all 4 quadrants (P < 0.001). The Van Herick grade of limbal anterior chamber depth increased (P < 0.001), whereas the number of eyes classified as occludable decreased (73%-33%, P < 0.001). Anterior chamber depth did not change significantly (2.41 mm +/- 0.28 mm vs. 2.42 mm +/- 0.30 mm, P = 0.43) as measured with optical pachymetry. Increased illumination increased the angle-opening measures, but induced a different alteration in peripheral iris morphology. Illumination-induced changes were greater after iridotomy than before laser treatment. CONCLUSIONS: In Asian eyes at high risk of developing APAC, sequential LPI produced a significant widening of the anterior chamber angle without deepening the anterior chamber centrally. LPI produces changes in iris morphology that are different from those caused by an increase in illumination, indicating that different mechanisms account for angle opening under these 2 conditions.     

原发性前房角关闭眼激光周边虹膜切开术后前房角形态学变化

目的 定量检测和评价原发性前房角关闭(PAC)眼行激光周边虹膜切开(LPI)术后前房角形态学变化.方法 临床病例系列研究.对入选的31例(54只眼)PAC患者于LPI术前、术后2周、6及12个月,进行眼科常规检查,定量检测超声活体显微镜(UBM)图像中前房角的各项参数.各随访时间点的UBM参数比较采用重复测量的方差分析,巩膜突前750μm与500 μm处各参数的比较采用配对t检验.结果 LPI术后前房深度较术前加深0.10 mm,但差异并无统计学意义(F=3.50,P＞0.05).LPI术前,巩膜突前750 μm处,前房角开放距离(66.2±51.6) μm,小梁网与虹膜间夹角5.0°±3.5°,前房角隐窝面积(0.025±0.017)mm2,小梁网与睫状突距离(571.0±97.2) μm;LPI术后2周、6及12个月,巩膜突前750 μm处,前房角开放距离分别为(165.0±70.3)、(185.8±68.5)及(196.1±77.7)μm,小梁网与虹膜间夹角分别为(11.9±4.9)、(13.3±4.8)及14.0°±5.4°,前房角隐窝面积分别为(0.058±0.024)、(0.065±0.023)及(0.068±0.026)mm2,小梁网与睫状突间距离分别为(647.1±113.0)、(701.8±93.4)及(670.1±95.4) μm,均较LPI术前增加,差异均有统计学意义(前房角开放距离:F =92.60,小梁网与虹膜间夹角:F=92.60,前房角隐窝面积:F=92.60,小梁网与睫状突间距离:F =34.00;P ＜0.05).术后前房角开放距离、小梁网与虹膜间夹角及前房角隐窝面积均较术前增加1倍以上.巩膜突前750 μm处检测参数的增加幅度均较巩膜突前500 μm处大(前房角开放距离:t=5.90,P＜0.05;小梁网与虹膜间夹角:t=2.70,P＜0.05;前房角隐窝面积:t=2.00;P =0.05).结论 LPI能显著增宽PAC眼的周边前房角,且随访观察1年期间前房角仍开放.巩膜突前750 μm处的参数比500μm处参数对评价周边前房角形态变化更为敏感.     

Quantitative evaluation of iris convexity in primary angle closure

PURPOSE: In eyes with primary angle closure (PAC), we quantitatively evaluated anterior bowing of the iris by means of ultrasound biomicroscopy (UBM). DESIGN: Retrospective, observational, and consecutive case series. METHODS: A total of 203 phakic eyes with PAC that had not undergone any surgical or laser treatment were included. Using UBM, we measured anterior chamber depth (ACD) and iris convexity (IC): the maximum distance from the posterior surface of the iris to the iris plane passing through the pupillary margin of the iris and iris root. RESULTS: The average IC was 0.22 +/- 0.1 mm, although there was considerable individual variation. The IC value was correlated weakly, albeit significantly, with age (r = 0.22, P < .01), and strongly with ACD (r = -0.57, P < .0001). CONCLUSIONS: In eyes with PAC, older age and a more shallow ACD appear to be important causes of increased forward bowing of the iris resulting from pupillary block.     

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.     

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.     

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。     

The anterior and posterior biometric characteristics in primary angle-closure disease: Data based on anterior segment optical coherence tomography and swept-source optical coherence tomography

Purpose:Obtaining a better understanding of the pathogenesis of primary angle-closure disease (PACD) still requires studies that provide measurements of anterior and posterior biometric characteristics together and that assess the relationship between them.Methods:In total, 201 eyes were enrolled in this cross-sectional study: 50 normal controls, 49 primary angle-closure suspect (PACS), 38 primary angle closure (PAC), and 64 primary angle-closure glaucoma (PACG) eyes. The anterior and posterior structural features were measured by anterior segment optical coherence tomography and swept-source optical coherence tomography.Results:All PACD groups had smaller anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume (ACV), angle opening distance at 750 μm from the scleral spur (AOD750), trabecular–iris space area at 750 μm from the scleral spur (TISA750), and angle recess area (ARA), as well as a larger lens vault (LV), than controls (all P < 0.001). The PACS and PAC groups had thicker iris thickness at 750 μm from the scleral spur (IT750) than controls (P = 0.017 and P = 0.002, respectively). Choroidal thickness (CT) was not statistically different among normal, PACS, PAC, and PACG eyes. Univariate and multivariate linear regression analysis revealed a significant association between thinner IT750 and increased CT in PACD eyes (P = 0.031, univariate analysis; P = 0.008, multivariate analysis).Conclusion:Thinner iris thickness was associated with increased CT in PACD eyes; however, the underlying mechanism needs further investigation.     

Anterior segment morphology after laser iridotomy in primary angle closure suspects

Purpose

To evaluate and compare the changes in anterior segment parameters in primary angle closure suspects before and after laser peripheral iridotomy and intrasession repeatability of measurements before laser iridotomy as assessed by Scheimpflug‐Placido disc topographer.

Methods

Before laser iridotomy, 56 eyes of 56 primary angle closure suspect patients underwent anterior segment analysis with the Sirius Scheimpflug‐Placido disc topographer system using glaucoma analysis mode, which was repeated a week after iridotomy. Anterior segment parameters such as central anterior chamber depth, central corneal thickness, anterior chamber volume and iridocorneal angle were analysed before and after laser iridotomy and compared with paired t‐test. Three consecutive scans were obtained to assess the intrasession repeatability of measurements before iridotomy by a single examiner and intraclass correlation co‐efficient was calculated. Multivariate regression analysis was performed to evaluate the predictors associated with iridocorneal angle narrowing.

Results

Intraclass correlation co‐efficient values ranged from 0.982 for anterior chamber volume to 0.998 for the iridocorneal angle. After laser iridotomy, mean central anterior chamber depth increased from 2.14 ± 0.29 mm to 2.21 ± 0.28 mm (p = 0.04), mean anterior chamber volume increased from 96.2 ± 16.98 mm³ to 98.14 ± 15.87 mm³ (p < 0.0001) and mean iridocorneal angle widened from 33.38 ± 3.96° to 34.82 ± 4.27° (p = 0.01), compared with pre‐iridotomy status. There was no change in central corneal thickness, intraocular pressure or pupil diameter. Multivariate regression analysis model showed that at one week after iridotomy, iridocorneal angle opening was positively correlated with age (β = 0.773, p = 0.005) and anterior chamber volume (β = 1.308, p < 0.0001).

Conclusions

Laser peripheral iridotomy induces significant changes in the 3‐D anterior segment morphology in primary angle closure suspect patients. The Scheimpflug‐Placido disc topographer provides reproducible measurements of the iridocorneal angle and other parameters measured and hence, may become clinically useful for non‐invasive detection of potentially occludable angles. Predictors of iridocorneal angle widening after iridotomy were older age and anterior chamber volume.

     

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.     

An ultrasound biomicroscopic study of the anterior segment in Indian eyes with primary angle-closure glaucoma

PURPOSE: To evaluate the presence of plateau iris in eyes with primary angle-closure glaucoma (PACG) after laser peripheral iridotomy by gonioscopy and ultrasound biomicroscopy and to evaluate the pathogenesis of this condition by comparing the UBM parameters of these eyes with those in normal subjects. PATIENTS AND METHODS: This prospective study was carried out in the Glaucoma clinic of a tertiary eye care center. A detailed clinical examination including applanation tonometry, indentation gonioscopy with a Sussman four-mirror gonioscope, and ultrasound biomicroscopic examination in one randomly selected eye of 55 patients (55 eyes) with PACG who had undergone laser peripheral iridotomy and 22 normal subjects (22 eyes). RESULTS: Among the PACG eyes, 40% (22/55) had an open angle (angle opening distance > 130 microns) and 60% (33/55) eyes had a narrow angle (angle opening distance 相似文献   

频域眼前节光学相干断层扫描仪(AS-OCT)对激光周边虹膜切开术后患者前房角结构定量检测

目的 利用频域眼前节光学相干断层扫描仪(anterior segment optical coherence tomography,AS-OCT)检测原发性闭角型青光眼及原发性房角关闭眼激光周边虹膜切开术后的房角参数,并探讨测量参数的选择及在青光眼患者筛查与随访中的临床意义.方法 选取原发性闭角型青光眼及原发性房角关闭患者共40例(55眼),其中原发性急性闭角型青光眼缓解期8例11眼,原发性急性闭角型青光眼临床前期20例(20眼),原发性房角关闭12例(24眼).应用频域AS-OCT量化评价激光周边虹膜切开术后房角结构,测量上方、下方、鼻侧、颞侧前房角(anterior chamber angle,ACA)、小梁虹膜夹角(trabecular-iris angle,TIA)、房角开放距离(angle open distance,AOD)、小梁虹膜空间面积(trabecular iris space area,TISA),对检查结果进行分析.结果 选取角膜内侧距巩膜突500 μm和750μm的点,分别测量上方、下方、鼻侧、颞侧四个方位的AOD、TIA、ACA、TISA,归为500系列和750系列.500系列及750系列TIA、ACA、AOD测量值均值均为颞侧最大,鼻侧最小;TISA测量均值下方最大、上方最小.Pearson相关性分析显示TIA500和ACA500(r=0.799、P=0.00)、TIA750和ACA750(r=0.799、P=0.00)、TIA500和TI-SA500(r=0.919、P=0.00)、TIA750和TISA750(r=0.920、P=0.00)均具有正相关关系.以TIA500为自变量x,TISA500为因变量y,得回归方程y=-0.300 +0.005x(F=1195,P=0.00),即TISA500与TIA500呈线性正相关关系.以TIA750为自变量x,TISA750为因变量y,得回归方程y=-0.440 +0.009x(F=854,P=0.00),即TISA750与TIA750呈线性正相关关系.750系列参数的变异系数在四个方位均小于500系列.结论 频域AS-OCT可用于原发性闭角型青光眼及原发性房角关闭患者术后的疗效评价与随访.在房角狭窄时,750系列参数变异系数更小,更具有临床应用价值.