Collaborative normal tension glaucoma study

PURPOSE OF REVIEW: Before this study was done, there was a difference of opinion concerning whether intraocular pressure (IOP) was involved in producing optic nerve damage when there was glaucomatous damage to the optic nerve and characteristic visual field loss, even though the IOP was in the statistically normal range. This article reviews the findings of a collaborative study aimed at finding the answer to this question. RECENT FINDINGS: The level of pressure influences the course of normal tension glaucoma, as evidenced by a slower rate of incident visual field loss in cases with 30% or more lowering of intraocular pressure. The rate of progression without treatment is highly variable, but often slow enough that half of the patients have no progression in 5 years. A faster rate occurs in women, in patients with migraine headaches, and in the presence of disc hemorrhages. Some patients may experience greater benefit from lowering of IOP than others, but further research is needed to be able to identify those most likely to benefit. SUMMARY: As a group, patients with normal tension glaucoma benefit from lowering of IOP. Variable rate of deterioration, as well as lack of progression in a substantial number in 5 years, suggest that treatment should be individualized according to the stage of disease and rate of progression. Traits that help predict risk and rate of progression and response to treatment are beginning to become known and, when fully known, will help guide management decisions.     

Diagnostics and therapy for normal tension glaucoma

Pooled data from "The Baltimore Eye Survey", "The Blue Mountains Eye Study", "The Beaver Dam Eye Study", "The Rotterdam Study" and "The Melbourne VIP" showed a strong age-dependent prevalence of open angle glaucoma. Patients younger than 60 years have a prevalence of open angle glaucoma of less than 1 %. Beginning with the age of 60 the prevalence increases exponentially. The prevalence of open angle glaucoma in persons in the 8(th) age decade reaches up to 5 %. Among these patients, 30-50 % have normal intraocular pressure. The diagnostics and therapy for open angle glaucoma with normal intraocular pressure (IOP), also called normal tension glaucoma, is a complex and often interdisciplinary challenge. Established causative factors for developing a glaucomatous optic nerve atrophy in normal tension glaucoma are: relatively increased IOP, older age, non-dippers (0-10 %) or extreme dippers (> 20 %) concerning nocturnal arterial blood pressure drop, small vessel disease with cardiovascular disease and cerebral microgliosis (white matter lesions), decreased blood flow in the optic nerve head, extreme dip of the optic nerve head blood flow in the morning, cerebral blood flow dysregulation and the epsilon4-allele polymorphism of the apolipoprotein E-gene. Clinical pathways are presented for the diagnostics and therapy for normal tension glaucoma.     

正常眼压性青光眼的诊断及治疗

正常眼压性青光眼由于发病隐匿,症状不典型,与原发性开角型青光眼临床症状相似,因此诊断治疗较为困难,并常被忽视.本文对其临床特点、诊断及治疗最新进展进行综述,以期对正常眼压性青光眼有更深入了解和进行更有效的治疗.     

正常眼压性青光眼病因学相关因素与分型

正常眼压性青光眼（NTG）的青光眼性视神经损伤和视野丢失在临床表现和发病机制上与原发性开角型青光眼（POAG）有一定差异。我们将NTG的发病机制可分为缺血缺氧型（存在低血压,合并心肌缺血、头痛和偏头痛、血浆内皮素-1水平增加、血小板聚集能力增加、缺血性颅脑病变等）、免疫异常型（存在单克隆丙种球蛋白血症以及抗视紫红质抗体、热休克蛋白的自身抗体、神经元特异性烯醇酶抗体、抗磷脂抗体异常）、神经退行性病变相关型（如Alzheimer病、Parkinson病）、内分泌异常型（如甲状腺功能低下）、眼压与颅内压失衡等,这将有助于NTG患者临床治疗方式的转变。（眼科,2012,21：19-23）     

The management of normal tension glaucoma

Objective : To outline the difficulties in making management decisions associated with normal tension glaucoma. To suggest treatment strategies according to the clinical presentation of the disease. Method : Literature review and findings based on clinical experience. Conclusions : The treatment of normal tension glaucoma involves many difficult decisions including whether to intervene and, if so, when and how to treat. Providing the patient with information is essential to gain co‐operation and confidence. At present, the treatment objectives are to prevent further visual field loss by reduction of intraocular pressure by 30 per cent or more. This may be achieved by using medical or surgical regimens. Recently, there has been emphasis on the use of neuroprotective drugs that may act independently of the effect of intraocular pressure lowering. The balance between protecting vision and iatrogenic damage is not always easy.     

Medical treatment of normal tension glaucoma

Normal-tension glaucoma was previously thought to be pressure insensitive, as medical treatment hardly reduced intraocular pressure and it did not prevent visual field loss. In the last decade, however, evidence has shown that the treatment of normal-tension glaucoma by lowering intraocular pressure can slow the deterioration of visual fields, hence the glaucomatous process. It was shown that a reduction of IOP of at least 30% is needed to induce a favorable alteration in the course of normal-tension glaucoma. New agents, such as prostaglandin analogs, the alpha(2)-adrenoceptor agonist brimonidine, and carbonic anhydrase inhibitors, have become available and may be of use in the treatment of normal-tension glaucoma. Monotherapy with prostaglandin analogs may meet the target of a reduction of IOP with 30%, but combination therapy will be needed in many cases. Few studies have been performed with brimonidine, travoprost, and bimatoprost, and it is suggested that more attention should be given to studies with these agents, as about 30% of patients with open angles and glaucomatous visual field defects have normal-tension glaucoma. Although neuroprotection is the goal of the future, no hard data are available yet which demonstrate that treatment with these agents will indeed result in preservation of visual fields.     

正常眼压性青光眼的危险因素

正常眼压性青光眼（normal tension glaucoma,NTG）在临床特征上除了眼压在正常范围外,其余均与开角型青光眼有许多相同之处,故以往一直被认为是开角型青光眼的一个亚型.但随着对此疾病的认识逐渐加深,发现其危险因素与高眼压性开角型青光眼有所不同,全身情况及眼局部因素都对NTG的发生发展产生影响,主要包括性别、年龄、脑供血不足、眼压波动、眼轴长度、屈光度等方面.     

Surgery for normal tension glaucoma.

The long term follow up of surgery in normal tension glaucoma is presented. One eye of 18 patients with bilateral progressive disease underwent fistulising surgery. Over follow up periods ranging from 2 to 7 years (50% > or = 5 years) the operated eye showed on average a 30% reduction in intraocular pressure (IOP). This was associated with a marked difference in the rate and number of retinal locations showing a progressive decline in retinal function, suggesting some protective function for lowering IOP in patients with normal tension glaucoma.     

正常眼压青光眼与原发性开角型青光眼的比较

正常眼压青光眼（ＮＴＧ）的发病率逐渐增加,日益受到眼科工作者的重视。ＮＴＧ发病隐蔽,早期诊断较其它青光眼显得更为困难和复杂,其发病机制、诊断标准及其与原发性开角型青光眼（ＰＯＡＧ）的异同等一系列问题仍无统一意见。就ＮＴＧ与ＰＯＡＧ的诊断标准,发病机制,临床表现,治疗原则以及相互关系等问题的研究进展等进行综述。     

正常眼压性青光眼的研究现状

正常眼压性青光眼(normal tension glaucoma,NTG)长期以来是一备受争议的话题.关于其发病机制,各学说均提出了有利证据,如NTG患者跨筛板压增大;筛板较为薄弱,对眼压的耐受力较差;氧化应激反应导致小梁网退行性改变及视网膜神经节细胞凋亡;眼部血流动力学异常;颈内动脉对视神经的机械压迫等.各因素之间既...     

Erythrocyte deformability in high-tension and normal tension glaucoma

The exact cause of primary open angle glaucoma is still unknown. Intraocular pressure is a major factor but it is impossible to explain the whole mechanism of glaucomatous optic nerve damage with only increased intraocular pressure. Other factors play important roles in the development of glaucoma. With this point of view, vascular factors have been implicated in the pathogenesis of glaucoma.We tried to determine the etiopathogenetic role of decreased erythhrocyte deformability in normal tension glaucoma and high-tension glaucoma. The study group consisted of 16 patients with the diagnosis of normal tension glaucoma, 17 patients with the diagnosis of high-tension glaucoma, and 24 patients as controls.Independent t-tests were used to compare the three groups two by two for age, hematocrit, mean cell volume, plasma protein level, cardiovascular risk factors, and erythrocyte deformability. There was no statistically significant relationship (p > 0.05) between the groups concerning the erythrocyte deformability. When we consider all of 57 patients, we found that both increasing age (> 60 years) and greater mean cell volume (> 84 fl) had a statistically significant relationship with decreased erythrocyte deformability (p < 0.05). When we performed Pearson correlation analysis, we found that only mean cell volume and erythrocyte deformability had a statistically significant relationship (r=0.31, p=0.02).We conclude that decreased erythrocyte deformability is not a major factor in the ethiopathogenesis of normal tension glaucoma and high-tension glaucoma.     

Ophthalmic segment aneurysm simulating normal tension glaucoma

A diagnosis of glaucoma is made in the presence of a characteristic form of optic neuropathy and visual field defect, with some regard to intraocular pressure. We encountered a case of compressive optic neuropathy caused by an aneurysm of the ophthalmic segment, which presented with signs suggestive of normal tension glaucoma. To our knowledge, this mode of presentation of an ophthalmic aneurysm has not been previously described.     

New thoughts on normal tension glaucoma.

Normal tension glaucoma (NTG) is considered a primary optic neuropathy within the glaucoma family. Whereas NTG shares many of the same pathologic characteristics as primary open angle glaucoma (POAG), there are several differences such as pattern of visual field defect and incidence of disc hemorrhaging. The most notable difference is that NTG does not manifest a recordable intraocular pressure (IOP) greater than 21 mmHg. Debate has existed as to whether NTG is a pressure-sensitive neuropathy and if pressure reduction affects the course of the disease. Likely, there are aspects in the pathophysiology of NTG that are both pressure sensitive and insensitive, and the etiology of NTG has never been adequately explained.     

Macular retinoschisis associated with normal tension glaucoma

Background  

To describe a case of macular retinoschisis in a patient with normal tension glaucoma without evidence of optic nerve pits or peripapillary retinoschisis.     

Optic disc findings in normal tension glaucoma

One hundred thirty stereo photographs of optic discs in patients with normal tension glaucoma (NTG) were reviewed in order to identify characteristics of the three following types of NTG: focal ischemic, senile sclerotic, and generalized cup enlargement. Twenty patients in each group were selected. Focal ischemic patients were more frequently women, had a higher incidence of migraine, a relatively smaller disc size, and localized superior scotoma that often threatened fixation. Senile sclerotic patients were generally elderly, had a higher incidence of surgery under general anethesia, had more ischemic heart disease or systemic hypertension, had a small rim area, and also had extensive peripapillary atrophy as well as combined diffuse and localized visual field defects. Generalized cup enlargement patients were younger, had a relatively larger disc size and a greater incidence of purely diffuse visual field loss. Results of our study suggest that the different characteristics of the groups are related to pathogenic mechanisms specific to each group.     

正常眼压性青光眼发病机制研究进展

正常眼压性青光眼在临床上被认为是眼底和视野出现特征性青光眼损害,而眼压始终正常的一种状态.正常眼压性青光眼在分类上被认为是原发性开角型青光眼的一个亚型,迄今有关其视神经损伤机制的研究主要集中在机械压力因素、血管及血流动力学因素、免疫调节因素及遗传因素等方面.     

C-reactive protein levels in normal tension glaucoma

PURPOSE: To determine C-reactive protein (CRP) levels in patients with normal tension glaucoma (NTG). METHODS: This study included 20 cases with NTG and 30 controls, with no history of ocular disease. Plasma CRP levels of all the study participants were determined using a highly sensitive CRP kit. RESULTS: Twenty cases (11 males, 9 females, mean age 69 +/- 5 years) with NTG and 30 age-matched controls (15 males, 15 females, mean age 68 +/- 6) were evaluated. Both groups had similar demographic parameters (age, sex, BMI). Plasma CRP levels were significantly higher in the NTG cases than in controls (median [range], 3.20 [0.17-8.4] mg/dL compared with 0.5 [0.1-3.2], P < 0.001). The mean plasma CRP level was significantly elevated in the NTG cases compared with the controls (3.21 +/- 0.6 mg/dL and 0.85 +/- 0.17 mg/dL, respectively, P < 0 0.01). CONCLUSION: Our findings suggest that higher CRP levels may be associated with NTG. It is possible that a vascular inflammatory process is involved in the etiology of this glaucoma.     

Corneal biomechanical properties in primary open angle glaucoma and normal tension glaucoma

PURPOSE: To determine and compare the corneal biomechanical properties between eyes with primary open angle glaucoma (POAG) and eyes with normal tension glaucoma (NTG). PATIENTS AND METHODS: Prospective cross-sectional study. Consecutive eligible POAG and NTG patients attending the Glaucoma Clinic had assessment of their corneal biomechanical properties-corneal hysteresis (CH) and corneal resistance factor (CRF)-using the Ocular Response Analyzer by an observer masked to the diagnosis. Exclusion criteria included previous intraocular surgery, corneal pathology, inflammatory connective tissue disease, and refraction of 5-dimensional or over. If both eyes were eligible, then the right eye was used for analysis. The main outcome measures were corneal hysteresis and CRF measurements. Data analysis was performed using the t test and general linear model. RESULTS: Eighty-one patients (80 whites) were analyzed. Forty had NTG, whereas 41 had POAG. Thirty-five were females. There was a statistically significant difference in mean CH (NTG 9.6+/-1.3 mm Hg; POAG 9.0+/-1.4 mm Hg; P=0.01), but not in mean CRF (NTG 9.9+/-1.4; POAG 10.8+/-1.7; P=0.06). The highest recorded Goldmann applanation intraocular pressure (IOP) was statistically significantly associated with lower CH (P=0.01) and higher CRF (P=0.02). CONCLUSIONS: There was a small but statistically significant difference in the mean CH between POAG and NTG (CH was higher in NTG). The highest recorded Goldmann applanation IOP was also statistically significantly correlated with lower CH and higher CRF, suggesting that alterations to the corneal biomechanical properties may occur as a result of chronic raised IOP in POAG.