Primary angle closure glaucoma: a developing world perspective

Primary angle closure glaucoma (PACG) is estimated to affect a significant proportion of the population worldwide. Of those affected, the majority reside in developing countries. In the developing world, more than 80% of the people afflicted with glaucoma are unaware that they have the disease, and visual impairment from PACG is more severe than from primary open-angle glaucoma. Considering the paucity of resources and competing opportunity costs, it is imperative that the developing world extrapolates current literature and exiting data sensibly, and develops cost-effective strategies for the detection and management of angle closure glaucoma. The number needed to treat (NNT) was used to extrapolate the trials for an individual patient. To extrapolate to the overall population (where applicable) the authors used the population attributable risk percentage (PAR%). For individual patient care, treatment of a primary angle closure suspect (PACS) has an NNT of 6 over 5 years to prevent one patient progressing to primary angle closure (PAC). The NNT for PAC to prevent PACG over 5 years is 5. The 'effective' PAR% for PACS is 56.4% and the 'effective' PAR% for PAC is 65%. This suggests both PACS and PAC are important health burdens but because of the absence of a good screening test and the opportunity costs involved, population-based screening will probably be unfeasible in developing countries.     

Primary angle closure glaucoma: a descriptive study in Scottish Caucasians

Purpose: The aim of this study is to describe the ocular and demographic features of Caucasian patients newly presenting with primary angle closure glaucoma and the proportion of workload it represents at a tertiary university hospital glaucoma service. Methods: A retrospective case notes review was conducted for all Caucasian patients newly diagnosed with narrow angles, primary angle closure, acute primary angle closure and primary angle closure glaucoma that were seen over a period of 2 years. Demographic and ocular variables were compared and statistical analysis was carried out with the paired t‐test and chi‐squared test. Number of primary open angle closure glaucoma and acute angle closure cases were compared with total number of new referrals to the department, new patients diagnosed with glaucoma and population numbers for the North East of Scotland. Results: One hundred and four patients were analysed. Twenty‐four (23.1%) had narrow angles, 30 (28.8%) had primary angle closure and 50 (48.1%) had primary angle closure glaucoma. Twelve (11.5%) presented with acute primary angle closure. There was no significant difference for gender, age, hypermetropia or visual acuity between groups. Primary angle closure glaucoma constituted 22.9% (50/128) of newly diagnosed glaucoma cases. Based on the 2001 Scotland census, the crude annual incidence of newly diagnosed primary angle closure glaucoma was estimated at 14.8 per 100 000 and 3.6 per 100 000 for acute primary angle closure in the over‐45‐year‐old population. Conclusion: Our study confirms that primary angle closure glaucoma is uncommon in Caucasians, but not as rare as originally perceived as it makes up a fair proportion (22.9%) of glaucoma workload.     

Primary phacoemulsification following acute primary angle closure glaucoma

Recent developments and clinical studies indicate that primary phacoemulsification and intraocular lens implantation are safe and effective for the surgical treatment of primary angle closure glaucoma (ACG) compared to conventional iridectomy or laser-iridotomy. When compared to control eyes treated using standard peripheral iridectomy, the outcome in terms of intraocular pressure control, adjunct anti-glaucoma medication, visual acuity, and the necessity for successive surgical interventions favored primary phacoemulsification and intraocular lens implantation. Earlier biometric data underline the importance of the "lens factor" in the pathogenesis of relative pupillary block in ACG obtained by Scheimflug image processing and ultrasound biomicroscopy. The vast improvements in modern cataract surgery combined with our current understanding of the pathogenesis of relative pupillary block in ACG indicate that lens extraction is a better procedure in uncontrolled angle closure glaucoma than conventional iridectomy.     

Primary angle closure glaucoma: Extracapsular cataract extraction or filtering procedure?

Summary An extracapsular cataract extraction (ECCE) with posterior-chamber-IOL was performed in 21 eyes of 20 patients with primary angle closure glaucoma (PACG; 2 suspects, 5 acute PACG, 14 chronic PACG). The ECCE was performed to improve the IOP. In 14 cases the ECCE was done in lieu of a filtering procedure. After the ECCE the anterior chamber deepened. The mean IOP was reduced from 31 mmHg preoperative to 16mmHg postoperative. Only 5 eyes needed additional medication after the ECCE. The IOP was reduced even if extensive peripheral anterior synechiae were diagnosed or after failed filtering procedures. The only temporary complication was the IOP-peak in the immediate postoperative period. It is concluded that an ECCE with PC-IOL should be seriously considered as the procedure of choice in PACG instead of a filtering procedure (or instead of a combined procedure).Presented in part at the Meeting of the Netherlands Ophthalmological Society, March 1987.     

Gonioscopy in primary angle closure glaucoma

Primary angle closure is a condition characterized by obstruction to aqueous humor outflow by the peripheral iris, and results in changes in the iridocorneal angle that are visible through gonioscopic examination. Gonioscopy in these eyes, however, can be difficult. This chapter discusses techniques that might help in the examination. These include beginning the examination with the inferior angle, methods to help in looking over the iris, cycloplegia, locating the corneal wedge, indentation, van Herick estimation, examining the other eye, and topical glycerin. Finally, there is a discussion about the pathology associated with the closed angle, with emphasis on the appearance of iris bombé, plateau iris, and the distinction between iris processes and peripheral anterior synechiae.     

Gonioscopy in primary angle closure glaucoma

Primary angle closure is a condition characterized by obstruction to aqueous humor outflow by the peripheral iris, and results in changes in the iridocorneal angle that are visible through gonioscopic examination. Gonioscopy in these eyes, however, can be difficult. This chapter discusses techniques that might help in the examination. These include beginning the examination with the inferior angle, methods to help in looking over the iris, cycloplegia, locating the corneal wedge, indentation, van Herick estimation, examining the other eye, and topical glycerin. Finally, there is a discussion about the pathology associated with the closed angle, with emphasis on the appearance of iris bombé, plateau iris, and the distinction between iris processes and peripheral anterior synechiae.     

原发性急性闭角型青光眼合并晶体脱位的超声生物显微镜观察

目的应用超声生物显微镜(ultrasound biomicrocopy，UBM)观察原发性急性闭角型青光眼合并晶体脱位的特点．探讨原发性急性闭角型青光眼合并晶体脱位的病因、临床表现及治疗效果。方法对2000年1月1日～2004年1月1日我院收治的19例(19眼)原发性急性闭角型青光眼合并晶体脱位者常规行裂隙灯及超声生物显微镜检查，观察晶体脱位范围、手术方式、术前术后视力、眼压等情况。结果19例19眼均被手术结果证实，晶体全脱位3眼，半脱位16眼。晶体脱位范围90度～360度，11眼行小梁切除术联合白内障超声乳化人工晶体植入术，8眼行小梁切除术联合晶体切除、前部玻璃体切除术、二期植入悬吊人工晶体。术前眼压大于21mmHg者17眼，术后眼压大于21mmHg者1眼。术前最佳矫正视力0．1以下者5眼，0．1～0．3者11眼，0．3以上者3眼；术后最佳矫正视力0．1以下者1眼，0．1～0．3者6眼，0．3以上者12眼。结论原发性急性闭角型青光眼合并晶体脱位可能由于急性发作期眼压骤然升高或应用降眼压药物引起眼压波动过大所致；也可能是患者年龄较大，晶体悬韧带部分断裂致晶体位置异常、瞳孔阻滞而引起急性闭角型青光眼急性发作。     

Neurotrophic factor delivery as a protective treatment for glaucoma

Glaucoma is a progressive optic neuropathy and a major cause of visual impairment worldwide. Neuroprotective therapies for glaucoma aim to ameliorate retinal ganglion cell degeneration through direct or indirect action on these neurons. Neurotrophic factor (NTF) delivery is a key target for the development of potential neuroprotective glaucoma treatments. This article will critically summarize the evidence that NTF deprivation and/or dysfunction plays a role in the pathogenesis of glaucoma. Experimental support for the neuroprotective potential of NTF supplementation in animal models of glaucoma will be reviewed, in particular for brain-derived neurotrophic factor, ciliary neurotrophic factor, and glial cell line-derived neurotrophic factor. Finally, the challenges of clinical translation will be considered with an emphasis on the most promising NTF delivery strategies including slow-release drug delivery, gene therapy, and cell transplantation.     

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％）,     

Five-year risk of progression of primary angle closure to primary angle closure glaucoma: a population-based study

OBJECTIVE: To report the 5-year progression to primary angle closure glaucoma (PACG) in a population-based cohort of primary angle closure (PAC) subjects. METHODS: A total of 37 patients diagnosed as PAC during a population-based study in 1995 were invited for re-examination in 2000. Patients underwent a complete ophthalmic examination including ocular biometry. Progression to PACG was based on optic disc damage and field defects on automated perimetry. RESULTS: In all, 28 of 32 PAC subjects who could be contacted presented for examination. Eight (28.5%; 95% CI 12-45%) had progressed to PACG; two of seven with appositional and six of 21 with synechial closure. All were advised laser peripheral iridotomy (LPI) in 1995; one of the nine who underwent LPI progressed compared to seven of 19 who refused LPI. Four of those originally diagnosed with appositional closure developed peripheral anterior synechiae. One eye of a person previously diagnosed with appositional PAC was reclassified as a primary angle closure suspect (PACS). There was no significant difference in biometric parameters between those who progressed and those who did not. None developed acute PACG or blindness due to glaucoma. CONCLUSION: In this population-based study of primary angle closure, the 5-year incidence of PACG was eight patients (28.5%; 95% CI 12-45%). We were unable to identify any features that predicted progression.     

Vogt-Koyanagi-Harada disease presenting as acute angle closure glaucoma at onset

Background: To investigate the clinical features of Vogt‐Koyanagi‐Harada (VKH) disease presenting as acute angle closure glaucoma at onset. Design: Retrospective non‐comparative case series. Participants: Four hundred and eighty‐six VKH patients seen from February 2001 to March 2010. Methods: The history and clinical findings of all patients were reviewed. Auxiliary examinations, including ultrasound biomicroscopy, fundus fluorescein angiography and optical coherence tomography, were performed in certain cases. Corticosteroids with or without cyclosporine A were used to treat these patients. Main Outcome Measure: Patients' demographics, clinical presentation and auxiliary examination findings. Results: Eight out of 486 VKH patients were misdiagnosed as acute angle closure glaucoma. The mean age of these eight patients was 55.6 years. Six patients were female. The mean intraocular pressure (IOP) at disease onset was 32.9 mmHg. All of these patients had a shallow anterior chamber and a narrow or closed angle at their first visit. The complaints of these patients were mostly headache and sudden decreased vision in both eyes. Alterations shown on ultrasound biomicroscopy included detachment of the ciliary body and peripheral choroid. The increased IOP did not respond to anti‐glaucoma therapy, but resolved following treatment with corticosteroids. The eye of one patient was enucleated after failed trabeculectomies prior to referral to our uveitis centre. Conclusion: VKH disease presenting with a bilateral increased IOP mostly occurs in older women. The strikingly decreased visual acuity associated with mild to moderate increased IOP is a clue to the diagnosis. The increased IOP responded well to corticosteroids but not to anti‐glaucoma treatment.     

Ultrasound biomicroscopic evaluation of anterior segment cysts as a risk factor for ocular hypertension and closure angle glaucoma

AIM:To investigate the relationship between the ultrasound biomicroscopic (UBM) features of anterior-segment cysts (ASCs) and increased intraocular pressure (IOP) as a risk factor for closed-angle glaucoma (CAG).METHODS:Totally 24 eyes with recently diagnosed ASCs were divided into two groups . First group with ASC and ocular normotension (n=13), second group with ASC and ocular hypertension (n=11). An ophthalmologic examination, including tonometry, slit-lamp biomicroscopy (SLBM), gonioscopy, fundoscopy, pentacam, and UBM, was performed. The features of the ASCs were compared with the IOP.RESULTS:ASCs were accurately diagnosed and delineated in 24 eyes using UBM. IOP was elevated in those ASCs with a secondary aetiology (P=0.027), iridociliary location (P=0.006), deformed shape (P=0.013), increased size (P=0.001) and elongated pupillary aperture (P=0.009). However, the count (P=0.343) of ASCs, anterior chamber depth (ACD; P=0.22) and axial lenght (AL; P=0.31) were not associated with ocular hypertension. Correlations were found between the IOP and ASC size (r=-0.712; P=0.003), anterior chamber angle (ACA; r=-0.985; P<0.001), angle opening area (AOA; r=0.885; P<0.001), angulation of iris (r=-0.776, P<0.001), and affected iris quadrant (r =-0.655, P=0.002).CONCLUSION:Ocular hypertension in some eyes with ASC might be associated with various mechanisms, including secondary aetiology, iridociliary location, deformed shape, increased size and elongated pupill, which can be determined by UBM.     

Role of phacoemulsification in angle closure glaucoma

 Cataract or clear lens extraction has been suggested as a treatment option for different spectrums of primary angle closure diseases. It might reduce the risk of progression of angle closure and/or glaucoma by helping to open the angle and control the intraocular pressure (IOP). Conventionally, medically uncontrolled primary angle closure glaucoma was treated with trabeculectomy or phacotrabeculectomy and acute primary angle closure was treated with laser peripheral iridotomy. However, recent randomized controlled trials have demonstrated greater promise of phacoemulsification cataract surgery alone for control of the IOP. In this report we review the current literature to evaluate the impact of cataract surgery upon preventing and controlling primary angle closure diseases.     

Argon laser iridotomy in angle closure glaucoma

Argon laser iridotomy was successfully performed in 30 eyes of glaucoma patients. A modified two stage procedure has been described to achieve a successful iridotomy in pigmented eyes. At the chosen site of laser iridotomy, partial thickness burns were applied in the first stage followed by a penetrating burns in the second stage. This minimised the complications associated with laser iridotomy and decreased the incidence of subsequent closure. At the end of 6 months follow up the success rate was 93.3 percent.