Unit12-A Ophthalmic Diseases-青光眼.doc

Unit 12 Ophthalmic Diseases眼部疾病Text A Glaucoma青光眼IntroductionPrimary open-angle glaucoma onset原发性开角型青光眼Glaucoma is a progressive optic neuropathy for which the major risk factor for visual loss is elevated intraocular pressure (IOP) 1 . In primary open-angel glaucoma ( POAG) ,the most common of the glaucomas，raised IOP occurs secondarily to a gradual reduction in the drainage of aqueous humour （房水）via the trabecular mesh work. Glaucoma can be present，however，in the presence of normal IOP ( normal-tension glaucoma).青光眼是一种退行性视神经病变，眼压升高(IOP)是其导致视力丧失的最主要风险因素。在原发性开角型青光眼疾病中，最常见的青光眼是由于眼压升高并通过小梁网导致房水减少。然而，在正常眼压升高下不会导致青光眼。Primary angle-closure glaucoma原发性闭角型青光眼Primary angle-closure glaucoma (PACG) is a condition in which elevation of IOP occurs as a result of obstruction of aqueous outflow by partial or complete closure of the angle by the peripheral iris. Unlike POAG, the diagnosis depends largely on examination of the anterior segment and careful gonioscopy. A normal optic nerve head and visual field do not preclude a diagnosis of PACG. This disease occurs in anatomically predisposed eyes and is frequently bilateral, although presentation of the acute form is often unilateral. Based on the mechanism of angle closure, two forms of PACG e are recognized： (a) pupillary block and (b) plateau iris syndrome, which is rare.原发性闭角型青光眼(PAGG)是条件性病变，主要取决于外围虹膜部分或完全封闭的角度大小，及阻碍房水外流导致眼压升高的程度。不像原发性开角型青光眼，PAGG诊断很大程度上依赖于眼前节和仔细的前房角镜检查。PAGG诊断不应该排除正常视神经乳头和视野检查。这种疾病发生于解剖结构异常眼并双侧频发，尽管严重的发病形式是单侧的。基于角度关闭的机制，PAGG的两种主要病理形式已被认识：主要是瞳孔关闭，稀有形式是高原虹膜综合征。Risk Factors风险因素Glaucoma is a progressive disease. However, the rate at which it progresses varies markedly from person to person. It was once believed that the only important factor to be controlled was the IOP，but it has become clear that many other factors affect the course of the disease. Because the major damage that occurs in most persons with glaucoma is deterioration of the optic nerve, the most important risk factor is the ability of the optic nerve to resist damage. Because most glaucomas are chronic conditions and because they are usually responsive to treatment, the ability of the patient to manage his or her own life is a critical factor in determining whether the patients glaucoma deteriorates. The patients with the best prognoses are those who know how to develop a relationship with the physician in which the physician acts as a junior partner, who take primary responsibility for their health, and who do those things most likely to keep them healthy. The major risk factors are as follows.青光眼是一种进行性疾病，然而，病情进展有着显著的人群差异性。曾经认为唯一的可控风险因素是IOP，但是，越发清晰的是还有其它风险因素影响病程。因为，大多数青光眼患者最主要的损伤是视神经退化，最重要的风险因素视神经抵抗损伤的能力。因为大多数青光眼发生是慢性疾病，且通常对治疗响应，病人个人生活管理能力是决定青光眼病程恶化与否至的关键因素。具有良好预测能力的患者，即知道如何去将负责其个人健康的医生作为良好合作伙伴，并与其良好的关系，这种患者更容易保持眼部健康。最主要的风险因素如下： Age. The average age at presentation is about 60 years ： prevalence increases thereafter.年龄。平均首患病龄为60岁，其后流行增加。 Gender. Females are more commonly affected than males by a ratio of 4: 1.性别。女性较男性更易发青光眼，男女患病比为4:1。 Race. In Caucasians the condition accounts for about 6% of all glaucomas and it affects approximately 1 : 1000 individuals over the age of 40 years. PACG is more common in South-East Asians, Chinese and Eskimos and is uncommon in black people.种族。高加索人种青光眼患者占到所有患者的6%，超过40岁患病个体中，高加索人种患病比例1:1000。相比于黑种人，亚洲东南部，中国人和爱斯基摩人易发青光眼。 Family history. First-degree relatives are at increased risk because predisposing anatomical factors are often inherited 21.家族史。一级亲属处于高风险性，因为遗传结构性发病诱因经常被继承。 Myopia is associated with an increased incidence of POAG 51 and myopic eyes are also more susceptible to high intraocular pressure-induced optic damage 1 . 近视与POAG发病率升高相关，近视眼易患高眼压诱发的视损伤Classification of Glaucoma青光眼分类The broad classification used in this chapter includes glaucoma, which indicates detectable tissue damage； preglaucoma, which indicates some finding ( e. g.，IOP of 80 mmHg) that makes it virtually certain that the patient will develop tissue damage ； and glaucoma suspect, which means that there is something about the patient that raises the suspicion of glaucoma, but does not denote with certainty whether tissue damage has occurred. Glaucoma suspects are individuals in whom the development of glaucoma is considered to be more likely than in individuals who possess none of the risk factors for glaucoma. The glaucoma suspect is further categorized as an individual who has a suspicious finding，such as an optic disc asymmetry，or an individual with a presumed predisposition to glaucoma because of some risk factor, such as a positive family history or pigment dispersion syndrome.本文使用广义分类法，包括可检测组织损伤的青光眼，条件性检出（例如眼压高于80 mmHG）可能会产生组织损伤的前青光眼。怀疑可能患青光眼，但不能确定是否已经发生组织损伤的疑似青光眼患者。疑似青光眼患者被认为更容易比没有任何风险因素的个体患青光眼。疑似青光眼根据个体可疑条件，比如视神经盘不对称或有确定家族史或者颜色分散综合征等风险因素进一步分类。Glaucoma is an optic neuropathy with characteristic appearances of the optic disc and specific pattern of visual field defects that is associated frequently but not invariably with raised IOP. Because the pathophysiology, clinical presentation and treatment of the different types of glaucoma are so varied, there is no single definition that adequately encompasses all forms. Understanding this concept helps to explain, for example, why one patient with glaucoma may have no symptoms while another experiences sudden pain and redness. Glaucoma may be (a) congenital (developmental) or (b) acquired 1. Further sub-classification into open-angle and angle-closure types is based on the mechanism by which aqueous outflow is impaired. The glaucoma may also be (a) primary or (b) secondary depending on the presence or absence of associated factors contributing to the pressure rise. In primary glaucomas, the elevation of IOP is not associated with any other ocular disorder whereas in secondary glaucomas, a recognizable ocular or non-ocular disorder alters aqueous outflow which, in turn, results in elevation of IOP. Secondary glaucomas may be acquired or developmental and of the open-angle or angle-closure type.青光眼是一种以视神经盘和特定视野缺陷为典型特征，时常但不总是与眼压升高(IOP)相关的视神经病。因为，不同类型青光眼在病理学，临床描述和治疗上都各不相同，没有唯一定义能够完全包括所有形式。理解这一定义有助于解释诸如无症状或一些经历突发疼痛和红肿的非青光眼病人。青光眼可能是先天性或获得性的。基于房水外流损害的机制可进一步将青光眼分为开角的和闭角的。青光眼也可以根据有助于眼压升高的相关风险因素是否存在分为原发性的和继发性的。在原发性青光眼中，眼压升高与其它的眼部疾病无相关性。而在继发性青光眼中，可辨认的眼部疾病或非眼部疾病依次改变房水外流，结果导致眼压升高。不论是开角型或闭角型的继发性青光眼都可能是获得性的或发展性的。Signs and Symptoms of Glaucoma青光眼的先兆和症状The stage of glaucoma refers to amount of damage. Although this refers typically to the optic nerve, it also applies to the health of other tissues, such as the cornea.In the earliest stage, the diagnosis is suspected but not definite. There is only a suspicious finding, such as an IOP above 30 mmHg or moderate disc asymmetry. The patient has no ocular symptoms and no evidence of definite damage. The physician may be suspicious that damage has occurred or may occur but cannot ascertain this at the time of the evaluation. The second stage is early glaucoma. In early glaucoma, the patient is still asymptomatic, but there is definite damage, such as an unmistakable nasal step in the visual field，a notch in the optic nerve, a hemorrhage on the optic nerve, or a minimal but definite afferent pupillary defect. The third stage is glaucomatous disease. The patient has some symptoms. He or she notices the field loss, is aware of halos or pain, or notices something else that interferes with visual function. The fourth stage is worsening disease. The patient notices functional impairment and is aware that the functional impairment is worsening.青光眼不同病程阶段的损害具有累积性。尽管这种损害涉及典型的视神经损伤，也经常累及其它健康组织，如角膜。在临床早期，诊断不能确诊，仅仅存在一些可疑发现，比如眼压高于30 mmHg或者轻微的视盘不对称。病人没有明显的视障和其它证据表明视伤害。医师仅仅是怀疑损害已发生或可能发生，但是在那时不能准确评估。第二阶段是青光眼早期，病人任然无症状，但有一定的损伤，比如明显的鼻侧阶梯视野，视神经刻痕，病理性视神经出血，或最小的但是明确的瞳孔生理性输入缺陷。病人有一些症状，如发现视野丢失，意识到和光晕和疼痛，或其它一些东西正在干扰视觉功能。第四阶段是病情恶化阶段，病人注意到视觉功能损伤且意识到在加剧中。Treatment of Glaucoma青光眼治疗Primary open-angle glaucoma (POAG), also referred to as chronic simple glaucoma, is a generally bilateral, but not always symmetrical disease, and its treatment is as follows.Target pressure.It is assumed that the pre-treatment level of IOP has damaged the optic nerve and will continue to do so (Fig. 12-1). An IOP level is identified below which further damage is considered unlikely (target pressure).The target pressure is identified taking into account the severity of existing damage. The level of IOP，the rapidity with which damage occurred (if that is known), as well as the age and general health of the patient. Therapy should maintain the IOP at or below the target level.原发性开角型青光眼（POAG）经常被称为慢性青光眼，通常是双侧的，但不总是有对称性，其治疗如下：限压人们假设预处理眼压水平对视神经有损伤并随之加剧。限压被用于解释当前损伤程度，限压以下的IOP造成进一步损伤是不可能的。IOP水平与损伤发生密切相关，和患者年龄和一般健康状况一样。治疗必须维持IOP在限压水平或以下。Monitoring is performed of the optic nerve and visual fields.视神经和视野检查In the event of further damage the target IOP is reset at a lower level ( Fig. 12-2). Although there is no “safe” level, progression is uncommon if the IOP is 16 mmHg 1. As the disease progresses the degree of redundancy or “ reserve capacity v within the visual system diminishes and the loss of each remaining ganglion cell inflicts a greater impact on visual function. Lower target pressures are therefore required in patients with advanced disease.Acute angle-closure glaucoma is a medical emergency. The first goals are to break the acute attack, usually with medical therapy to relieve permanently the pupillary block with neodymium： yttrium-argon-gamet ( Nd： YAGlHl ) laser iridotomy.进一步的损害发生限制眼压被复位在更低水平。尽管没有安全水平，连续性眼压低于16 mmHg，随着疾病发展的冗余度或视觉系统可用容量的减少及每神经节细胞的丢失，将对视觉功能造成较大的影响。重症患者因此需要低的限压。急性闭角型青光眼需要急诊，第一目标是阻止急性发作，通常通过钕剂治疗并解除持续性瞳孔封闭，激光虹膜切开术。Medical therapy医学治疗 Acetazolamide 500 mg intravenously and 500 mg orally (not slow-release) provided there is no vomiting.静脉注射500 mg乙酰唑胺，如果不呕吐可口服500 mg非缓释乙酰唑胺。 Topical therapy局部治疗Pilocarpine 2% two drops to both eyes.Dexamethasone (or equivalent) q. i. d.A beta-blocker if there is no systemic contraindication.双眼滴药2滴2% 匹鲁卡品地塞米松或等价药物非系统禁忌症可使用贝尔塔受体阻滞剂Surgical therapy Nd：YAG laser iridotomy ：Permanent relief of pupillary block is achieved with Nd： YAG laser peripheral iridotomy. If one eye had an acute attack, the fellow eye should prompt prophylactic laser iridotomy to prevent an acute attack.激光虹膜切除术：使用Nd-激光虹膜切除术永久性解除瞳孔封闭。如果一只眼睛急性发作，对侧眼应及时使用激光切除术保护其急性发作。 Surgical peripheral iridectomy.The anterior chamber angle may appear open or show peripheral anterior synechiae of variable extension after the attack. Permanent relief of pupillary block is achieved with surgical therapy.As for the chronic angle-closure glaucoma laser peripheral iridectomy is the initial treatment of choice. However, if most of the anterior chamber angle is closed, laser iridotomy will not be helpful in controlling the IOP. Long-term aqueous suppressants and, sometimes, filtering surgery, may be required. If more than one quadrant of the anterior chamber angle has appositional closure and opens with indentation gonioscopy，laser iridotomy may be enough to arrest the progression of the disease.外科虹膜切除术急性发作后，前房角出现或显示外周虹膜黏连动态性扩展，使用外科虹膜切除手术解除永久性瞳孔闭合。慢性闭角型青光眼外周激光切除术作为初始治疗手段，然而，如果大多数前房角是关闭的，激光切除术将不会有利于控制IOP。长期房水抑制药物，有时，手术筛选，是必要的。如果不只一个前房象限角同位闭合且始于房角镜，激光切除术将会加剧疾病发展。New Wordsglaucoma gbik