Mechanism and Etiology of Primary Chronic Angle Closure Glaucoma

The ocular anatomic features, pupil-blocking force, status of angle synechiae closure and positivity of provocative tests were compared between the primary chronic angle closure glaucoma (PCACG) and primary a-cute angle closure glaucoma (PAACG) by using ultrasonic biometry, computerized anterior ocular segment image processing technique, gonioscopy and provocative tests. The studies showed that the anterior chamber depth of PAACG was shallower than that of PCACG; the pupil-blocking force of PAACG was stronger than that of PCACG; the status of angle synechiae closure of PCACG were mainly creeping synechiae closure; the positivity of mydriasis test was much higher (46. 01%) in PCACG than that (6. 8%) in PAACG after iridectomy. These facts suggest approximately half of the PCACG cases may be multi-mechanism to contribute to the angle closure besides the mechanism of pupillary block. Therefore, the authors emphasis that the pupillary block must be eliminated as well as the other mechanism for the treatment     

激光周边虹膜成形术治疗虹膜切除术后暗室俯卧试验阳性的原发性闭角型青光眼

目的　评价激光周边虹膜成形术治疗虹膜切除术后暗室俯卧试验阳性的原发性闭角型青光眼的临床效果。方法　对激光周边虹膜切除术后暗室俯卧试验阳性的 34例 (5 6只眼 )原发性闭角型青光眼 (非眼外引流手术指征 ,前房角粘连 <1/2周前房角范围 )患者行激光周边虹膜成形术。其中急性闭角型青光眼 2 7例 (49只眼 ) ,慢性闭角型青光眼 7例 (7只眼 )。对患者治疗前后的周边前房深度、前房角、眼压、视野及周边虹膜形态进行详细的对比观察 ,并行暗室俯卧试验及散瞳试验检查。患者术后随访 1～ 4年。结果　所有患者治疗后周边前房深度均明显加深 ,静态前房角镜检查小梁网可见范围增宽。随访期间患者未发生高眼压、前房角进行性粘连及视野损害 ,暗室俯卧试验及散瞳试验均阴性。结论　虹膜切除术后暗室俯卧试验阳性的原发性闭角型青光眼的发病机制是当瞳孔散大时 ,异常的周边虹膜组织堵塞小梁网而引起高眼压 ,瞳孔阻滞因素不起主导作用。激光周边虹膜成形术可以明显改变此类青光眼患者 (前房角粘连 <1/2周前房角范围 )的周边虹膜形态 ,从而控制病情进展。     

青光眼-白内障联合术后患者屈光误差及其与术前眼球生物学参数的相关性

目的　对比分析原发性急性闭角型青光眼(PAACG)、原发性慢性闭角型青光眼(PCACG)、原发性开角型青光眼(POAG)患者行青光眼-白内障联合手术（青白联合手术）后3个月的屈光状态,评估术前眼球生物学参数对患者术后屈光状态的影响。方法　回顾性临床研究。选择2020年2月至2021年2月于山西省眼科医院行青白联合手术的青光眼合并白内障患者90例（108眼）,其中PAACG组30例（33眼）,PCACG组30例（38眼）,POAG组30例（37眼）。所有患者术前均采用IOLMaster 700测量眼轴长度、中央角膜厚度、角膜曲率、前房深度、晶状体厚度、白到白距离（WTW）,使用仪器自带的SRK-T公式计算人工晶状体度数及预留屈光度。术后3个月对患者进行综合验光,计算术后屈光误差。比较三组患者术后3个月的屈光误差分布,及术前眼球生物学参数与屈光误差的相关性。结果　三组患者间术前中央角膜厚度、角膜曲率、WTW差异均无统计学意义(均为P>0.05)。POAG组较PAACG组和PCACG组患者术前眼轴更长、前房更深、晶状体更薄,差异均有统计学意义(均为P<0.05),PAACG组与PCACG组患者间术前眼轴长度、前房深度、晶状体厚度相比差异均无统计学意义(均为P>0.05)。术后3个月,PAACG组、PCACG组、POAG组患者绝对屈光误差分别为(0.53±0.75)D、(0.51±0.70)D、(0.05±0.47)D。远视误差组患者术前眼轴长度短于近视误差组,术前前房深度浅于近视误差组,术前晶状体厚度厚于近视误差组,两组间相比差异均有统计学意义(均为P<0.05);两组患者间术前中央角膜厚度、角膜曲率与WTW之间差异均无统计学意义(均为P>0.05)。术后屈光误差与术前眼轴长度、前房深度均呈负相关(r=-0.62、-0.48,均为P=0.00),与术前晶状体厚度呈正相关(r=0.54,P=0.00),与术前中央角膜厚度、角膜曲率、WTW均无显著相关性(均为P>0.05)。结论　使用SRK-T公式计算人工晶状体度数时,PAACG、PCACG患者比POAG患者呈现较大的屈光误差,且多为远视误差。术前短眼轴、浅前房及厚晶状体患者青白联合手术后更趋于远视误差。     

中国人闭角型青光眼房角关闭机制的研究

目的 对中国人原发性闭角型眼光眼（闭青）房角关闭机制进行研究,为按发病机制分类提供依据。方法采用超声生物显微镜和诊断性的治疗方法对１２６例（１２６只眼）原发性闭青的房角及房角相关解剖结构进行活体、实时、定性及半定量观察分析。结果根据ＵＢＭ房角及房我有相关解剖结构的观察,可将原发性闭青房锄头 闭机制分为单纯性瞳孔阻滞型（４８例,４８只眼,占３８．１％）,单纯性非瞳孔阻滞（９例,９只眼,占７．１％）,     

Angle-closure Glaucoma: The Role of the Lens in the Pathogenesis, Prevention, and Treatment

Primary angle-closure glaucoma is a major cause of blindness worldwide. It is a disease of ocular anatomy that is related to pupillary-block and angle-crowding mechanisms of filtration angle closure. Eyes at increased risk for primary angle-closure are small with decreased axial length, anterior chamber depth, and filtration angle width, associated with a proportionately large lens. Angle-closure glaucoma afflicts Asian and Eskimo eyes more frequently than eyes in other races with similar predisposing dimensions. The treatment of primary angle closure addresses its causal mechanisms. Laser peripheral iridotomy equalizes the anterior and posterior pressures and widens the filtration angle by reducing the effect of pupillary block. Argon laser peripheral iridoplasty contracts the iris stroma to reduce angle crowding and is helpful for some affected eyes. Lensectomy dramatically widens the angle and eliminates pupillary block. Clinical reports of lensectomy with posterior chamber intraocular lens implantation in the treatment of acute, chronic, and secondary angle-closure glaucoma describe very favorable results. The appropriate role for lensectomy in the management of primary angle closure, however, remains unproven. Prospective, randomized clinical trials are ongoing to determine the value and comparative risks and efficacy of lensectomy versus medical therapy, laser peripheral iridotomy, laser iridoplasty, and filtration procedures for the treatment of acute and chronic primary angle closure and for the prevention of chronic angle-closure glaucoma, both after and in place of laser peripheral iridotomy.     

晶状体摘出术治疗原发性闭角型青光眼的研究进展

晶状体的形态和位置改变所引起的浅前房、瞳孔阻滞及房角关闭是诱发原发性闭角型青光眼(PACG)的因素之一.晶状体摘出术可以增加前房深度,解除瞳孔阻滞;而晶状体摘出术联合房角分离术可使关闭的房角重新开放,防止周边房角前粘连.近年来采用晶状体摘出术治疗PACG的研究取得较大进展,而其作用机制的研究、治疗效果的评价及仍然存在的问题等日益受到关注.就PACG的发生和发展与晶状体改变的关系、晶状体摘出术在治疗PACG中的作用、效果及手术的安全性评价等进行综述.     

The threshold of pupil-blocking force

The purpose of this study was to quantitate the dynamic changes which take place in the anterior eye segment during the prone position test. The pupil-blocking force was measured before and after the prone position test (PTT) by a method of image analysis using a computer. The changes in the magnitude of pupillary block were evaluated. The mechanics of this provocation seems to be both pupillary block and direct lens block angle-closure. Pupil-blocking force standardizes the assessment of the eyes with relative pupil-block. The present results provide valuable information in the analysis of the mechanism of primary angle-closure glaucoma and also contribute to the determination of a real value for the threshold of the pupil-blocking force (approximately 0.1 or greater), followed by a clinically significant elevation of intraocular pressure.     

原发性青光眼患者血流变学和血流动力学的变化(英文)

目的:探讨原发性青光眼患者血粘度水平改变及眼血流动力学变化对视神经的损害的意义及二者间的关系。方法:测定原发性开角型青光眼、急性闭角型青光眼、慢性闭角型青光眼和正常对照组(老年性白内障患者)各20例的全血比粘度、血浆比粘度、纤维蛋白原进行分析比较,并使用彩色多普勒成像技术检测其眼动脉(OA)和视网膜中央动脉(CRA)的收缩期血流速度(PSV)、舒张末期血流速度(EDV)、阻力指数(RI)、频谱形态和监听频声。各组间的均数差异比较用t检验,并将原发性青光眼患者的血流变指标分别与CDI血流动力学各项指标进行线性相关分析。结果:3组青光眼与对照组比较除纤维蛋白原差异无统计学意义外,其余各项血流变指标均显著升高;OA、CRA的PSV和EDV有明显下降,而RI明显增高;3组青光眼的血粘度各项指标与OA和CRA的PSV、EDV呈负相关,与RI呈正相关;正常对照组内血粘度水平与血流动力学各项指标无相关性。结论:原发性青光眼患者眼部存在不同程度的血液循环障碍,其血粘度水平升高可能是原发性青光眼视神经损害的潜在性危险因素;CDI对球后血管血流改变有较高的敏感性,在青光眼早期诊断及预后判断等方面均有重要的参考价值。     

Acute increase of intraocular pressure releases ATP into the anterior chamber

Throughout the body, mechanical perturbations are transduced into neurochemical signals by the release of ATP from non-neuronal cells. As an increased intraocular pressure (IOP) can initiate mechanical changes, we hypothesized that extracellular levels of ATP might be increased in the anterior chamber of human patients with primary acute angle closure glaucoma (PAACG). ATP levels in aqueous humor samples were determined using the luciferin-luciferase assay. Samples were obtained from 18 controls scheduled for cataract extraction and from 14 subjects with angle closure glaucoma during paracentesis. All subjects with angle closure glaucoma had remarkably elevated levels of ATP in their aqueous humor. The mean ATP concentration was ninefold higher for patients with angle closure glaucoma than for control. The concentration of ATP was correlated with IOP levels, further supporting a causal relationship. ATP levels were not influenced by the duration of the PAACG attack, suggesting the rate of ATP release was sustained. We conclude that increased IOP leads to increased levels of extracellular ATP in the anterior chamber. This elevated ATP may contribute to the extreme pain experienced by subjects with angle closure glaucoma, and may serve as a source of elevated adenosine in the anterior chamber.     

Case-based approach to managing angle closure glaucoma with anterior segment imaging

This is a case-based approach to the diagnosis and management of angle closure glaucoma of a variety of causative factors, with a special emphasis on the use of advanced anterior segment imaging including ultrasound biomicroscopy and anterior segment optical coherence tomography. Although all angle closure is caused by iridotrabecular contact, the cause of angle closure glaucoma is classified based on the site of primary blockage of aqueous movement from anterior to posterior: pupillary block, plateau iris, lens-related, and posterior causative factors. Although gonioscopy is traditionally used to visualize the angle structures and estimate the angle width, objective and reproducible measurement of the anterior chamber angle can best be obtained with advanced anterior segment imaging. In this review article, we demonstrate the utility of anterior advanced imaging to identify underlying mechanisms in cases of angle closure glaucoma in guiding directed management.     

A method of measuring pupil-blocking force in the human eye

A new method of measuring pupil-blocking force in the human eye is reported. The anterior segment of the eye was photographed using a slit-lamp apparatus and the color photographs then analyzed with a digitizer for converting the optical image of the anterior eye segment into the true image using a computer. This technique permits precise estimation of the relative positions of the anterior chamber, such as pupil margins, iris root insertions, and central anteroposterior pupillary axis. Pupil-blocking force was calculated from these data according to Hook's law. There was a statistically significant difference in pupil-blocking force between normal subjects (mean ± SD, – 0.027 ± 0.029; = Young's module) and patients with primary angle-closure glaucoma (mean ± SD, + 0.134 ± 0.068) (P < 0.001). In patients with primary angle-closure glaucoma, during an acute attack the pupil-blocking force was markedly high. This technique for measuring pupil-blocking force will provide valuable data for the analysis of the mechanism of primary angle-closure glaucoma.     

原发性闭角型青光眼房角关闭机制的研究进展

本文总结了原发性房角关闭与原发性闭角型青光眼的概念,综述了原发性闭角型青光眼房角关闭机制分为单纯性瞳孔阻滞型、单纯性非瞳孔阻滞型和多种机制共存型,并对导致房角关闭的相关因素做了分析。     

前房型人工晶体植入术后继发性青光眼

目的 了解前房型人工晶体（ａｎｔｅｒｉｏｒｃｈａｍｂｅｒｉｎｔｒａｏｃｕｌａｒｌｅｎｓ,ＡＣ－ＩＯＬ）植入术后对眼压,房角的影响及继发性青光眼的发生情况。方法 回顾调查６２只眼ＡＣ－ＩＯＬ植入术后,随访期为３个月至７年,平均３１个月,眼部检查着重度的检查,白内障类型以外伤性及老年性为主,手术方式包括眼前段切除术或白内障囊外摘除（ｅｘｔｒａｃａｐｓｕｌａｒｃａｔａｒａｃｔｅｘｔｒａｃｔｉｏｎ,ＥＣＣ     

白内障超声乳化术治疗闭角型青光眼临床分析

目的:评价白内障超声乳化吸除联合人工晶状体植入术治疗临床前期原发性闭角型青光眼的疗效。方法:2006-06/2007-12就诊于我院白内障患者中,38例(38眼)经术前检查确诊为原发性闭角型青光眼临床前期,行白内障超声乳化吸除联合人工晶状体植入术,比较术前及术后周边前房深度、房角宽度、青光眼暗室加俯卧试验、眼压、视力。结果:术前所有患者周边前房<1/4CT,静态前房角镜检查>3/4象限不见巩膜突,青光眼暗室加俯卧试验阳性;术后所有患者周边前房加深,房角加宽,青光眼暗室加俯卧试验均为阴性。手术前后眼压无统计学差异,所有患者视力均提高。结论:白内障超声乳化吸除联合人工晶状体植入术可以作为原发性闭角型青光眼临床前期一种有效治疗手段。     

Effect of changing from concomitant timolol pilocarpine to bimatoprost monotherapy on ocular blood flow and IOP in primary chronic angle closure glaucoma.

The aim of the present prospective masked study was to assess the effect of bimatoprost monotherapy on ocular blood flow and intraocular pressure (IOP) in eyes of primary chronic angle closure glaucoma patients already on concomitant timolol and pilocarpine. Thirty two patients of bilateral primary chronic angle closure glaucoma (PCACG) on topical timolol 0.5% twice a day and pilocarpine 2% three times daily were switched over to bimatoprost 0.03% once daily in both eyes. Intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) were recorded before and after starting bimatoprost and were followed up every four weeks for three months. Bimatoprost had statistically significant (p < 0.05) mean IOP reduction from 19.3 +/- 6.6 to 13.5 +/- 4.5 mmHg (30.5%) and there was improvement from 858 +/- 260 to 1261 +/- 321 microL/min (46.8%) in mean pulsatile ocular blood flow (p < 0.05). Conjunctival hyperemia (32%) was the most common adverse effect of bimatoprost. Bimatoprost 0.03% monotherapy improved ocular blood flow and provided a better diurnal IOP control than concomitant timolol-pilocarpine in eyes with primary chronic angle closure glaucoma and was found to be well tolerated.     

Angle closure in younger patients

PURPOSE: Angle-closure glaucoma is rare in children and young adults; only scattered cases associated with specific clinical entities have been reported. We evaluated the findings in patients aged 40 or younger with angle closure in our database. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Our database was searched for patients aged 40 years or younger with angle closure. Data recorded included age at initial consultation, age at the time of diagnosis, gender, slit-lamp examination, gonioscopy, ultrasound biomicroscopy (from 1993 onward), clinical diagnosis, and therapy. Patients with prior incisional surgery were excluded, as were patients with anterior chamber proliferative mechanisms leading to angle closure. RESULTS: Sixty-seven patients (49 females, 18 males) met entry criteria. Mean age at the time of consultation was 34.4 +/- 9.4 (standard deviation) years (range, 3-68 years). Diagnoses included plateau iris syndrome (35 patients); iridociliary cysts (8 patients); retinopathy of prematurity (7 patients); uveitis (5 patients); isolated nanophthalmos (3 patients); relative pupillary block (2 patients); Weill-Marchesani syndrome (3 patients); and 1 patient each with Marfan syndrome, miotic-induced angle closure, persistent hyperplastic primary vitreous, and idiopathic lens subluxation. CONCLUSIONS: The etiology of angle closure in young individuals differs from the older population and is typically associated with structural/developmental ocular anomalies rather than relative pupillary block. After laser iridotomy, these eyes should be monitored for recurrent angle closure and the need for additional laser or incisional surgical intervention.     

Management of glaucoma after retinal detachment surgery

Secondary glaucoma may complicate retinal detachment surgery. Intraocular pressure (IOP) elevation has been described after scleral buckling procedures and vitrectomy with intravitreal injection of gas or silicone oil. Angle-closure glaucoma after scleral buckling develops because of congestion and anterior rotation of the ciliary body. Medical therapy and laser iridoplasty are usually successful in controlling IOP, but the presence of conjunctival scarring and recession and retinal hardware after scleral buckling procedures can make surgical management challenging. Intravitreal injection of expansile gases like sulfur hexafluoride (SF6) and perfluoropropene (C3F8) may produce secondary angle-closure glaucoma with or without pupillary block. Aspiration of a portion of the intraocular gas may be needed, especially if IOP is elevated to a level that may compromise ocular perfusion. Glaucoma also can develop after intravitreal injection of silicone oil secondary to pupillary block, inflammation, synechial angle closure, rubeosis iridis, or migration of emulsified or nonemulsified silicone oil into the anterior chamber. A prophylactic inferior iridectomy at the time of surgery serves to prevent pupillary block. Patients with medically uncontrolled glaucoma after silicone oil injection may require oil removal with or without concurrent glaucoma surgery.     

原发性闭角型青光眼周边虹膜切除前后房角相关结构的研究

目的：探讨我国不同类型原发性闭角型青光眼对周边虹膜切除术的反应,对不同房锄头 闭机制的闭角青光眼寻找合理的治疗方案。方法：采用房角检查技术,超声生物显微镜眼前段活体结构检查技术,ＵＢＭ暗室试验技术,ＵＢＭ眼前段图像处理技术,对不同类型闭角型青光眼周边虹膜切除术前后的房角状态,房 关解剖结构进行了定性及半定量观察,结果：周边虹膜切除术后,房角ＵＢＭ检查发现,临床经过呈慢性经过的闭青（慢闭）,特别是房     

Post-miosis changes in the anterior chamber structures in primary and lens-induced secondary chronic angle-closure glaucoma

To evaluate post-miosis changes in the anterior chamber structures in various angle-closure glaucomas (ACG). Totally 14 eyes of primary chronic angle-closure glaucoma (PCACG), 12 eyes of lens-induced secondary chronic angle-closure glaucoma (LSACG) and 14 healthy eyes were recruited. After miosis, for PCACG group, intraocular pressure (IOP) and anterior chamber depth (ACD) changed not significantly, while anterior chamber angle widened significantly. LSACG group showed a significant increase in IOP, decrease in ACD, and narrowing in anterior chamber angle. Healthy eyes showed significant decreases in IOP and anterior chamber parameters. Thus, miosis could widen the anterior chamber angle of patients with PCACG, while increase the narrowing of anterior chamber angle and IOP of patients with LSACG. We should pay attention to the distinction between PCACG and LSACG patients and the proper administration of pilocarpine in the treatment of patients with chronic ACG.     

High Resolution Ultrasonography in Eyes with Angle-Closure Glaucoma Associated with the Cicatricial Stage of Retinopathy of Prematurity

Background Angle-closure glaucoma in children at the cicatricial stage of retinopathy of prematurity (ROP) has been thought to be caused by the anterior displacement of the lens–iris diaphragm resulting from contraction of a retrolental fibrous membrane. Other possible mechanisms include pupillary block and ciliary block.Cases Three patients (three eyes) at the cicatricial stage of ROP with angle-closure glaucoma were examined by high-resolution ultrasonography before and after peripheral iridectomy.Observations High-resolution ultrasonography preoperatively showed that the angle was closed. A retrolental fibrous membrane was attached behind the lens. After the iridectomy, ultrasonography showed an open angle, and the intraocular pressure was normal.Conclusions The angle closure in our three patients was caused mainly by a pupillary block and could be treated by peripheral iridectomy. Jpn J Ophthalmol 2005;49:312–314 © Japanese Ophthalmological Society 2005