Management of ischemic optic neuropathies

Ischemic optic neuropathies (IONs) consist primarily of two types: anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). AION comprises arteritic AION (A-AION: due to giant cell arteritis) and non-arteritic AION (NA-AION: due to other causes). PION consists of arteritic PION (A-PION: due to giant cell arteritis), non-arteritic PION (NA-PION: due to other causes), and surgical PION (a complication of several systemic surgical procedures). These five types of ION are distinct clinical entities etiologically, pathogenetically, clinically and from the management point of view. In the management of AION, the first crucial step with patients aged 50 and over is to identify immediately whether it is arteritic or not because A-AION is an ophthalmic emergency and requires urgent treatment with high-dose steroid therapy to prevent any further visual loss in one or both eyes. Patients with NA-AION, when treated with systemic corticosteroid therapy within first 2 weeks of onset, had significantly better visual outcome than untreated ones. Systemic risk factors, particularly nocturnal arterial hypotension, play major roles in the development of NA-AION; management of them is essential in its prevention and management. NA-PION patients, when treated with high-dose systemic steroid therapy during the very early stages of the disease, showed significant improvement in visual acuity and visual fields, compared to untreated eyes. A-PION, like A-AION, requires urgent treatment with high-dose steroid therapy to prevent any further visual loss in one or both eyes. There is no satisfactory treatment for surgical PION, except to take prophylactic measures to prevent its development.     

急性后部缺血性视神经病变

脑血管意外和视网膜血管的循环障碍都是老年常见病。视盘筛板区,后睫状动脉的循环障碍,也可引起大家所熟知的前部缺血性视神经病变(AION),而筛板后至视交叉间的视神经血管,是否也可引起急性循环障碍,从而导致视功能的损害,由于球后视神经的血运情况难于检查,过去未能引起足够的重视。1980年日本下奥仁〔1〕报导了该部缺血引起的后部缺血性视神经病变     

后部缺血性视神经病变临床观察

目的:通过回顾性研究,探讨后部缺血性视神经病变(pos-teriorischemicopticneuropathy,PION)的临床表现、发病机制、诊断及治疗预后。方法:对9例(12眼)PION患者常规行眼部检查及全身检查,并排除压迫性、炎性、青光眼性或其它视神经疾病。行中医综合治疗。观察视力、视野、眼前节及眼底体征。结果:9例12眼均有不同程度视力下降及视野缺损;眼底视盘及视网膜正常6眼,视盘变淡或苍白6眼。经治疗的8例10眼,有效率70%。结论:PION是一种独立的临床眼病,诊断强调排除其它视神经疾病或眼病,中医综合治疗有助于视力改善。     

Studies on the pathogenesis of anterior ischemic optic neuropathy

The pathogenesis of nonarteritic anterior ischemic optic neuropathy (AION) was investigated, on the basis of clinical findings from a patient with nonarteritic AION and experimental study of the vascular architecture of the human optic nerve head. The patient's visual field examination revealed a wide Bjerrum scotoma. This visual field defect suggests that the mechanism of the onset of nonarteritic AION might be similar to that of glaucoma. Fluorescein fundus angiography (FFA) findings suggest that the peripapillary choroidal circulation might recover more easily from perfusion disturbance than the rest. Further, experimental study of the human optic nerve heads revealed that the circle of Zinn forms a complete vascular circle and that small branches from this circle extend to the peripapillary choroid or the optic nerve head, and that the intraneural vascular meshwork is less dense than that in the retrolaminar portion. Based upon the above clinical findings and experimental results, the pathogenesis of nonarteritic AION is postulated as follows: (1) The blood flow in the circle of Zinn is decreased by stenosis of the posterior ciliary artery (PCA). (2) Hypoperfusion is produced in the whole optic nerve head. (3) As in glaucoma, arcuate nerve fibers are first affected, resulting in the onset of nonarteritic AION with arcuate visual field defect or altitudinal defect.     

Ischemic optic neuropathy. Pathogenesis, clinical features, diagnostics and treatment

Ischemic optic neuropathy is a common cause of visual loss in the older population. This disease is classified into anterior and posterior type according to the location the lesions. The anterior type is due to transient nonperfusion or hypoperfusion of the ciliary circulation in the optic nerve head. The etiology of this disease is multifactorial. The most important risk factors for developing anterior ischemic optic neuropathy (AION) include hypertension, nocturnal hypotension, diabetes mellitus, atherosclerosis and small cup in the optic disc. AION presents with sudden painless loss of vision, pale edema of the optic disc, afferent papillary defect and visual field defects, typically in lower quadrants. Posterior ischemic optic neuropathy (PION) is a rare condition and diagnosis of it usually is made only after other causes of a retrobulbar optic neuropathy have been excluded. There are three distinct subtype of PION: perioperative, arteritic and nonarteritic. They are characterized by acute visual loss, variable visual field defects, relative afferent pupillary defect and normal optic disc.     

Treatment of anterior ischemic optic neuropathy: Clues from the bench

Anterior ischemic optic neuropathy (AION) is due to optic nerve head ischemia, and there is currently no effective treatment. Age is a significant risk factor for both arteritic and nonarteritic AION (NAION), although we do not fully understand the changes that occur in aging that lead to selective vulnerability of the optic nerve head. Arteritic AION, which is most often seen in the setting of giant cell arteritis, is caused by vasculitis and thromboembolism of the ophthalmic circulation leading to impaired perfusion of the short posterior ciliary artery and infarction of the optic nerve head. More commonly, AION is nonarteritic, and vision loss is typically altitudinal and noted most commonly upon awakening. NAION has been associated with a variety of risk factors, including disc-at-risk, vascular risk factors including diabetes, vasospasm and impaired autoregulation, nocturnal hypotension, and sleep apnea. This review summarizes the clinical presentation of non-arteritic AION and arteritic AION associated with giant cell arteritis and the current and future treatment approaches for human NAION based on lessons from photochemical thrombosis models of NAION.     

Ischaemic optic neuropathy

Ischaemic optic neuropathy is of two types: anterior (AION) and posterior (PION), the first involving the optic nerve head (ONH) and the second, the rest of the optic nerve. Pathogenetically AION and PION are very different diseases. AION represents an acute ischaemic disorder of the ONH supplied by the posterior ciliary artery (PCA), while PION has no specific location in the posterior part of the optic nerve and does not represent an ischaemic disorder of any definite artery. The most important step towards a logical understanding of the underlying causes, clinical features, pathogenesis and rational management of AION, is to understand the basic scientific issues involved; these are discussed in some detail. AION clinically is of two types: (1) that due to giant cell arteritis (arteritic AION: A-AION) and (2) non-arteritic AION (NA-AION). NA-AION, the more common of the two, is one of the most prevalent and visually crippling diseases in the middle-aged and elderly, and is potentially bilateral. NA-AION is a multifactorial disease, with many risk factors collectively contributing to its development. Although there is no known treatment for NA-AION, reduction of risk factors is important in decreasing chances of involvement of the second eye and of further episodes. Our studies have suggested that nocturnal arterial hypotension is an important risk factor for the development and progression of NA-AION. The role of nocturnal arterial hypotension in the pathogenesis of NA-AION and management of nocturnal hypotension is discussed. Potent antihypertensive drugs, when used aggressively and/or given at bedtime, are emerging as an important risk factor for nocturnal hypotension, and there is some evidence that NA-AION may be occurring as an iatrogenic disease in some individuals. A-AION, by contrast, is an ocular emergency and requires immediate treatment with systemic corticosteroids to prevent further visual loss. The clinical parameters which help to differentiate the two types of AION, and their respective management are discussed.     

Diabetic optic neuropathies: clinical features

Optic disc neovascularization, anterior and posterior ischemic optic neuropathy (AION and PION), diabetic papillopathy and Wolfram's syndrome are known conditions affecting the optic nerve in diabetics. Analysis of frequencies of AION in diabetes and two cases with and without background diabetic retinopathy are reported. The literature concerning the pathogenesis of diabetic papillopathy and its clinical similarity to optic disc vasculitis are briefly discussed.     

前部缺血性视神经病变的临床分析

观察分析前部缺血性视神经病变（anterior ischemic optic neuropathy,AION）的发病危险因素、临床特征及治疗效果。 方法：回顾性分析46例51眼AION患者全身及眼部危险因素、临床症状、眼底、FFA、视野改变。治疗和控制全身性疾病,全身或局部应用糖皮质激素、血管扩张剂、神经营养剂,评价治疗效果。 结果：患者平均年龄53±10岁,全身性疾病包括高血压、糖尿病、高脂血症、低血压、心脑血管疾病等。47.06%患者诉视力突然下降,64.71%患者眼底检查示视盘呈灰白色水肿,33.33%患者视野表现偏盲性缺损,56.86%患者FFA早期视盘弱荧光,晚期荧光增强。经治疗80.39%患者视力提高,视野缺损改善。 结论：AION是多病因眼病,高血压、糖尿病、高脂血症、心脑血管疾病等是其发生的危险因素。突然视力下降、视盘灰白水肿、偏盲性视野缺损、FFA视盘早期弱荧光、晚期强荧光是其典型表现。综合治疗后患者可恢复一定视力视野。     

Ischemic optic neuropathy

Ischemic optic neuropathy is one of the major causes of blindness or seriously impaired vision, yet there is disagreement as to its pathogenesis, clinical features and especially its management. This is because ischemic optic neuropathy is not one disease but a spectrum of several different types, each with its own etiology, pathogenesis, clinical features and management. They cannot be lumped together. Ischemic optic neuropathy is primarily of two types: anterior (AION) and posterior (PION), involving the optic nerve head (ONH) and the rest of the optic nerve respectively. Furthermore, both AION and PION have different subtypes. AION comprises arteritic (A-AION – due to giant cell arteritis) and, non-arteritic (NA-AION – due to causes other than giant cell arteritis); NA-AION can be further classified into classical NA-AION and incipient NA-AION. PION consists of arteritic (A-PION – due to giant cell arteritis), non-arteritic (NA-PION – due to causes other than giant cell arteritis), and surgical (a complication of several systemic surgical procedures). Thus, ischemic optic neuropathy consists of six distinct types of clinical entities. NA-AION is by far the most common type and one of the most prevalent and visually crippling diseases in the middle-aged and elderly. A-AION, though less common, is an ocular emergency and requires early diagnosis and immediate treatment with systemic high dose corticosteroids to prevent further visual loss, which is entirely preventable.Controversy exists regarding the pathogenesis, clinical features and especially management of the various types of ischemic optic neuropathy because there are multiple misconceptions about its many fundamental aspects. Recently emerging information on the various factors that influence the optic nerve circulation, and also the various systemic and local risk factors which play important roles in the development of various types of ischemic optic neuropathy have given us a better understanding of their pathogeneses, clinical features and management. This knowledge should help us not only to manage them better but also to reduce their incidence. For example, clinically, the evidence that about 40% of NA-AION eyes experience spontaneous improvement in visual acuity and that systemic steroid therapy during early stages in both NA-AION and NA-PION has a significant beneficial effect for visual outcome are encouraging developments. This review discusses the current concepts on various issues related to various types of ischemic optic neuropathy.     

Optic disc structure in anterior ischemic optic neuropathy

The etiology of anterior ischemic optic neuropathy (AION), when not associated with giant cell arteritis, is usually unknown. Clinical, pathologic, and experimental studies have not determined a cause. The optic disc appearance in both the involved and normal fellow eye was studied in 51 patients with acute nonarteritic AION. The number of discs (both involved and fellow) without a physiologic cup was significantly greater than would be expected from normal population studies. The etiology of nonarteritic AION may be related to the anatomic configuration of the optic nerve.     

糖尿病性视乳头病变

目的:探讨糖尿病视乳头病变与糖尿病视网膜病变分期、糖尿病病程之间的关系。方法:回顾分析302例荧光素眼底血管造影、眼底镜、视野计检查确诊的糖尿病视网膜病变患者。根据我国现行的DR诊断分期标准对DR进行分期。统计分析糖尿病视乳头病变的发生率以及糖尿病视乳头病变与糖尿病病程、糖尿病视网膜病变分期之间的关系。结果:DR98例135眼有PD(32.4%),包括76眼发生缺血性视乳头病变,54眼发生视乳头水肿,5眼发生视神经萎缩。Ⅰ期DR糖尿病视乳头病变的发生率为8.3%,Ⅱ期DR糖尿病视乳头病变的发生率为21.1%,Ⅲ期DR糖尿病视乳头病变的发生率为32.4%,Ⅳ期DR糖尿病视乳头病变的发生率为44.8%,Ⅴ期DR糖尿病视乳头病变的发生率为76.2%。结论:糖尿病视乳头病变是糖尿病视网膜病变患者视力损害的常见原因,糖尿病视乳头病变发生率随糖尿病病程延长以及糖尿病视网膜病变的加重而增加.     

Two presentations of nonarteritic ischemic optic neuropathy

Background

Nonarteritic ischemic optic neuropathy (NAION) is the most common acute optic neuropathy in adults over the age of 50. Patients affected notice sudden and painless loss of vision in 1 eye, often upon awaking. Studies have found that the opposite eye may be affected in approximately 15% to 20% of cases within a 5-year period. NAION vision loss results from an ischemic event often affecting the short posterior ciliary arteries. This results in optic nerve pallor, nerve fiber layer defects, and corresponding visual field defects.

Case Reports

Two cases of NAION are discussed here. The first patient, a 57-year-old woman, had a 10-year history of visual symptoms, and the second, a 66-year-old man, presented in less than a week after first noticing symptoms. Both had predisposing systemic risk factors and resultant visual field loss and decreased visual acuity.

Conclusions

Predisposing factors for NAION include small cup-to-disc ratios of the optic nerve, obstructive sleep apnea, nocturnal hypotension, diabetes, and other vascular diseases. The vision loss is irreversible, and there is no known effective treatment to prevent subsequent disc atrophy or recurring episodes.     

Anterior ischemic optic neuropathy: Nonarteritic form in small and giant cell arteritis in normal sized optic discs

Summary By estimating cup/disc ratios in fellow eyes it has been assumed that nonarteritic anterior ischemic optic neuropathy (AION) occurs more often in small optic nerve heads. Correcting the photographic magnification we used absolute size units to measure 33 affected and 25 fellow optic discs with nonarteritic AION and 7 affected and 7 fellow optic nerve heads with arteritic AION.The affected and fellow discs with nonarteritic AION (2.37 + -0.29 mm² and 2.31 + -0.31 mm²) were significantly (p<0.001, Mann-Whitney-test) smaller than 457 normal optic nerve heads (2.69 +-0.70 mm²). They were significantly (p<0.001; Mann-Whitney-test) larger than optic nerve heads with pseudopapilledema or drusen. Affected and fellow optic nerve heads with arteritic AION were not significantly different in size from normal discs but significantly (p<0.005) larger than the discs affected by nonarteritic neuropathy. There were no significant form differences between the pathologic and normal discs.Optic disc morphometry can be helpful in the differentiation of nonarteritic and arteritic AION: Non-arteritic AION occurs more often in small optic discs, arteritic AION is more often in normal sized optic nerve heads.Parts of this study have been presented at the meeting of the Optic Nerve Study Group held in Padova/Italy May 13–14th 1987, and at the meeting of the Swiss Ophthalmologic Society, held in Engelberg September 9–12.     

Recovery of visual field defects in ischemic optic neuropathy and idiopathic optic neuritis]

Fifty-four eyes of 41 patients with optic nerve disease demonstrating acute visual field defects without any traumatic, compressive, or other known etiology were classified into four categories. Those showing poor recovery of visual field defects were ischemic optic neuropathy which was subclassified into either anterior ischemic optic neuropathy (AION) or posterior ischemic optic neuropathy (PION) according to the ophthalmoscopic changes in the optic nerve head. Those showing good recovery of visual field defects were idiopathic optic neuritis which was subclassified into either papillitis or retrobulbar neuritis according to the ophthalmoscopic pathology of the optic disc. Patients with ischemic optic neuropathy were significantly older than those with optic neuritis. All eyes with optic neuritis showed good recovery of vision, whereas those with ischemic optic neuropathy showed varying outcomes of vision. With regard to the pattern of field defect, central or paracentral scotoma was predominant in all but eyes with AION in which altitude defect predominated. Pale swelling of the optic nerve head and angiographic evidence of circulatory disturbance in the optic disc or adjacent choroid were common findings in eyes with AION, whereas such findings were never observed in eyes with papillitis. The amplitude of pattern visual evoked potential was significantly lower in eyes with PION than in those with retrobulbar optic neuritis. Four patients classified as optic neuritis developed into multiple sclerosis in the follow-up study. It was concluded that poor recovery of visual field defect is one of the most convincing evidences for the diagnosis of ischemic optic neuropathy.     

曲安奈德联合葛根素治疗非动脉炎性前部缺血性视神经病变

目的观察曲安奈德联合葛根素治疗非动脉炎性前部缺血性视神经病变(nonarteritic anterior ischemic optic neuropa-thy,NAION)的临床疗效。方法收集我院近年来确诊的NAION患者84例(84眼),随机分为2组,各42例,对照组静脉滴注葛根素400mg,每日1次;治疗组在对照组的治疗基础上,加用曲安奈德注射液20mg患眼球后注射,1周后重复注射1次;疗程均为2周。观察治疗前后患者视力、视野、图形视觉诱发电位、闪光视网膜电图、盘周视网膜神经纤维层厚度变化情况。结果治疗组治疗前后视力分别为0.24±0.12、0.57±0.27,差异有显著统计学意义(t=7.921,P<0.01);对照组治疗前后视力分别为0.25±0.15、0.46±0.62,差异有统计学意义(t=2.185,P<0.05);治疗组治疗后视力高于对照组,差异有统计学意义(t=2.893,P<0.05)。治疗后2组患者平均视野缺损值降低和平均光敏感度提高,与治疗前比较,差异均有统计学意义(均为P<0.05);治疗组患者平均视野缺损值及光敏感度好转程度较对照组高,差异均有统计学意义(t=2.423、2.704,均为P<0.05)。2组患者治疗后图形视觉诱发电位的P100波潜伏期缩短、振幅提高,治疗前后比较差异均有统计学意义(均为P<0.05);治疗组患者P100波潜伏期及振幅的改善程度较对照组好,差异均有统计学意义(t=2.433、2.228,均为P<0.05)。治疗组患者视网膜振荡电位(OPs)总和振幅提高,与对照组比较,差异有统计学意义(t=2.515,P<0.05)。治疗组盘周4个象限视网膜神经纤维层厚度减轻幅度均高于对照组,差异均有统计学意义(均为P<0.05)。结论曲安奈德联合葛根素治疗NAION疗效优于单纯葛根素,能安全有效地促进视功能恢复。     

X-recessive angiopathic opticopathy

A familial optic atrophy with X-recessive heredity, distinct from Leber's optic atrophy (LOA), is described. The symptoms are: slight to moderate pallor of the papillomacular bundle at the disc possibly preceded by some hyperaemia of the disc, telangiectasia on the disc with normal retinal vessels, occurrence in the second decade of life, slow progression with often subclinical visual loss, a small relative central scotoma with an intact peripheral visual field, slight acquired tritanopia and deuteranopia, and vasomotor headaches. The disease may exhibit severe exacerbations with loss of vision to 1/60, provoked by vasoconstrictors and reacting favourably to vasodialators. This acute loss of vision is associated with ischaemia of the disc, a deep central scotoma with marked disturbance of colour vision in the form of an acquired deuteranopia, and sensoparalytic pupils. This is followed by increasing pallor of the disc, slow resolution of the central scotoma with a permanent reduction in the central light sensitivity, markedly disturbed Visual Evoked Potentials (VEP), acquired deuteranopia and normal ERG and EOG.In contrast to all hereditary opticopathies so far described, fluorescein angiography showed a disturbance of perfusion in the peripapillary choroid and the prelaminar part of the optic nerve. A similar disturbance of perfusion is described in anterior ischaemic optic neuropathy (AION) and low-tension glaucoma. To these acquired, non-hereditary vascular opticopathies, which usually occur late in life, will have to be added the X-recessive vascular optic atrophy which we describe here, for which we propose the name: X-recessive angiopathic opticopathy. The differential diagnosis from some other hereditary, especially X-recessive, optic atrophies is discussed.     

Nonarteritic posterior ischemic optic neuropathy treated with optic nerve sheath decompression Report of two cases

Posterior ischemic optic neuropathy (PION) is a rare form of ischemic optic neuropathy that is thought to be due to impaired blood flow in the posterior circulation of the optic nerve. It presents with acute monocular loss of vision and impaired visual field in the presence of a normal appearing optic disc. Infectious, demyelination, and compressive optic neuropathy must be excluded in order to make the diagnosis of nonarteritic PION (NPION). To our knowledge, this is the first report of NPION successfully treated with optic nerve sheath fenestration. We treated two patients within four and six days of the onset of symptoms. Visual acuity and visual fields improved rapidly and permanently in both patients.     

Posterior ischemic optic neuropathy. III. Clinical diagnosis

14 cases of posterior ischemic optic neuropathy (PION) were clinically analyzed, in whom we excluded known etiologies of optic nerve disturbances and confirmed the decreased blood supply to the posterior portion of the optic nerve. On the basis of our clinical findings, we have proposed the following criteria for the diagnosis of idiopathic PION: (1) sudden onset of unilateral visual disturbance in older patients; (2) normal optic disc, subsequently developing simple optic atrophy; (3) hypertensive and arteriosclerotic changes in the retinal vessels; (4) varying degrees of impaired vision, variable visual field defects; (5) associated systemic disease such as hypertension, diabetes mellitus, hyperlipemia, hypotension, etc.; (6) exclusion of other demonstrable causes of optic nerve disturbances, and (7) confirmation of abnormal hemodynamics in the posterior portion of the optic nerve by carotid angiography, ophthalmodynamography, ophthalmodynamometry and fluorescein fundus angiography.     

前部缺血性视神经病变的眼底荧光血管造影

报导了22例34眼前部缺血性视神经病变(AION)的眼底荧光血管造影所见。病程早期主要表现为视盘部分性或全部性低荧光或高荧光。全视盘高荧光者,荧光索渗漏从静脉早期才开始出现并渐增强。病程超过2周的病例,视盘均呈低荧光并逐渐出现视神经萎缩的特征。在不同病程,常可见视盘附近局限性脉络膜灌注不良的低背景荧光表现。认为眼底荧光血管造影对AION的鉴别诊断及病理过程的深入认识有重要价值。