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.     

Vascular optic neuropathy in diabetes mellitus

A retrospective analysis of clinical profiles of 20 patients with anterior and posterior ischemic optic neuropathy and diabetic papillopathy was used to evaluate optic neuropathy in diabetes. We found that vascular optic neuropathy in diabetic patients resulted from microangiopathy, macroangiopathy, and certain structural factors in the optic nerve head.     

Ischaemic optic neuropathy complicating cardiopulmonary bypass.

Bilateral anterior ischaemic optic neuropathy occurred in two patients undergoing cardiopulmonary bypass grafting. The causes may have been vasoconstriction of the posterior ciliary arteries by increased circulating angiotensin and diminished ciliary blood flow in the setting of systemic hypotension and elevated intraocular pressure.     

Spheniodal mucocele causing bilateral optic neuropathy and ophthalmoplegia

Sphenoid sinus mucocele comprises only 2% of all paranasal sinus mucoceles. In literature, there is a case report on sphenoidal mucocele causing bilateral optic neuropathy, with unilateral partial recovery and cranial nerve palsy, but we did not come across any literature with bilateral optic neuropathy and ophthalmoplegia together caused by spheno-ethmoidal mucocele. We present such a rare case of spheno-ethmoidal mucocele causing bilateral optic neuropathy and unilateral sixth nerve palsy who had postsurgery, unilateral good vision recovery, and complete resolution of sixth nerve palsy.     

Chronic asymptomatic ischemic optic neuropathy. A report of two cases in adults with diabetes mellitus

Two adult diabetic patients with chronic asymptomatic optic neuropathy attributed to an ischemic etiology are reported. In one case the typical syndrome of ischemic optic neuropathy occurred in one eye, while the fellow eye had asymptomatic hyperemic optic disc edema that persisted for 6 months without optic atrophy. A minor visual field defect initially detected in that eye resolved spontaneously in 1 month. In the second case, a recent onset, middle-aged diabetic developed bilateral optic neuropathy and optic disc edema that persisted for 12 months, with minimal signs of visual dysfunction. Axoplasmic transport blockage from low-grade ischemia to the optic nerve may cause acute or chronic optic disc edema with minimal or no visual symptoms.     

Myopia and diabetes mellitus as modificatory factors of glaucomatous optic neuropathy

Myopic deformation of the eye and metabolic alterations of the nerve tissue of patients with diabetes may modify glaucomatous optic neuropathy (GON). Blockage of axonal transport of neurotrophic factors (NTFs) is the event crucial to understanding the factors that affect GON. The primary, but not sole, blockage site is at the lamina cribrosa (LC). Other than this primary site of damage at the LC, 7 other factors may explain atypical nerve fiber layer (NFL) defects and the vulnerability of the nerve fibers in eyes with high myopia and glaucoma: a second point of blockage at the edge of the posterior scleral foramen; ectatic strain on the NFL; ectasia and distortion of the LC; association of a hypoplastic optic disc; thin and weak collagen fibers; peripapillary chorioretinal atrophy; and myopic neuropathy. Among diabetic patients, diabetic neuropathy in the retinal NFL is present initially, and increased resistance to aqueous outflow leads to ocular hypertension. Superimposition of GON on diabetic neuropathy and ocular hypertension in patients with diabetes may enhance their susceptibility to nerve damage. Results of a meta-analysis study suggested a positive association between diabetes mellitus and glaucoma whereas other reports suggested that leakage of vascular endothelial growth factor, a survival mechanism of ischemic neural tissue, and enhanced stiffness of the LC as a result of diabetic glycation may protect neurons from apoptosis. Thus, modification of GON as a result of diabetes remains controversial.     

同型半胱氨酸与2型糖尿病合并前部缺血性视神经病变的相关性

目的：探讨血清同型半胱氨酸(Hcy)水平与2型糖尿病合并前部缺血性视神经病变(AION)的关系。

方法：选取2016-01/2019-04于河北省眼科医院就诊的2型糖尿病患者100例,依据是否并发AION分为未合并AION组(A组,53例)和合并AION组(B组,47例),另选取同期健康体检者38例为对照组(C组)。检测受检者血Hcy、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、肌酐(Cr)、糖化血红蛋白(HbA1c)等生化指标和血压、最佳矫正视力(BCVA)情况,分析2型糖尿病合并AION患者血Hcy水平与上述临床指标的相关性。

结果：B组受检者血Hcy水平(13.87±5.02μmol/L)显著高于A组(11.83±3.49μmol/L)和C组(11.06±3.62μmol/L)(均P<0.05),且B组受检者HHcy发生率(36.2%)明显高于A组(11.3%)和C组(10.5%)。校正年龄、TG、LDL-C、Cr、糖尿病病程、收缩压和舒张压后,2型糖尿病合并AION患者血Hcy水平与HbA1c水平呈正相关(r=0.517,P=0.001),与BCVA呈负相关(r=-0.353,P=0.026)。

结论：血清Hcy可能参与了2型糖尿病患者AION的发病过程,其可作为防治2型糖尿病合并AION的潜在靶点。     

Ischaemic optic neuropathy--a combined mechanism.

A clinical pathological study is reported of a patient who developed bilateral ischaemic optic neuropathy following a massive gastrointestinal haemorrhage with associated vascular complications in watershed areas of the myocardium and brain. Additional factors of giant cell arteritis and diabetic ketoacidosis contributed to the unique pathology. The distribution of infarction to the optic nerve has been related to known studies on the blood supply of the optic nerve.     

Anterior ischemic optic neuropathy in type I diabetes

Anterior ischemic optic neuropathy (A.I.O.N.) may cause optic disc edema in type-I diabetes. A.I.O.N. affects diabetic patients of all ages. Such optic neuropathy is more likely to become bilateral in diabetics than in the non-diabetic subjects. A 41-year-old diabetic insulin-dependent woman presented A.I.O.N. in RE; 5 years later, the same affection occurred in LE. The clinical course was relatively benign in both eyes, with good functional restitution. The patient was treated by high doses of Sodium Salicylate and Sulfinpyrazone. The pathogenesis of optic disc edema in type-I diabetes is, according to Hayreh (1981), ischemia of different grade in the district of the posterior ciliary arteries: microangiopathy, rheological anomalies and atherosclerotic added lesions produce a variability of clinical pictures of increasing seriousness. Our case has an intermediate position in such a continuous spectrum. The VEP supported the diagnosia of A.I.O.N.     

Orbital actinomycosis associated with painful ophthalmoplegia. Actinomycosis of the orbit

PURPOSE: To evaluate a case of orbital actinomycosis presenting as Tolosa-Hunt syndrome in a patient with a history of carcinomas of the kidney and breast. METHODS: A woman with ingravescent painful ophthalmoplegia was brought to our observation. Brain and orbital and total body CT scans showed the presence of two orbital neoformations and a miliary pattern of dissemination in the lung. The initial diagnosis, which pointed to secondary localisations of the previous kidney and breast tumours, was changed to orbital and pulmonary actinomycosis following microbiological analysis of lung biopsy samples. RESULTS: Prolonged antibiotic therapy with synthetic penicillin completely resolved the case. CONCLUSIONS: Actinomycosis is a very rare infection that may also affect the orbit and its association with a pulmonary dissemination is highly unusual. It is important to consider this type of infection among the causes of painful ophthalmoplegia.     

Topless optic disk syndrome without maternal diabetes mellitus.

PURPOSE: To describe four cases of topless optic disk syndrome without maternal diabetes mellitus. METHOD: Four patients had incidentally discovered inferior visual field defects. RESULTS: Ophthalmoscopic examinations in all four patients disclosed superiorly displaced entrances of the central retinal artery and thinning of the superior peripapillary nerve fiber layers. One patient had a superior peripapillary crescent with pallor of the superior disk. These clinical findings were consistent with a diagnosis of superior segmental optic hypoplasia, the topless disk. None of the patients had mothers who had diabetes. CONCLUSIONS: The topless optic disk syndrome can occur in the absence of maternal diabetes mellitus.     

Human extraocular muscles in mitochondrial diseases: comparing chronic progressive external ophthalmoplegia with Leber's hereditary optic neuropathy

AIMS: To compare the ultrastructural aspects of human extraocular muscles in two types of mitochondrial disease: chronic progressive external ophthalmoplegia (CPEO) and Leber's hereditary optic neuropathy (LHON). METHODS: Muscle samples of the medial rectus obtained from surgery in a sporadic case of CPEO associated with deleted mitochondrial DNA, and post mortem in a case of 3460/ND1 LHON were processed for electron microscopy (EM). The medial rectus from an autoptic time to fixation matched control was used to exclude postmortem artefacts. RESULTS: The CPEO specimen revealed focal areas of disruption and abnormalities of mitochondria in some muscle fibres, creating a "mosaic-like" pattern. In the LHON specimen a diffuse increase in both number and size of mitochondria (mean diameter 0.85 mum v 0.65 mum of control, p<0.0001) with swollen appearance and disorganised cristae filled all spaces of sarcoplasmic reticulum. In some areas the excessive number of mitochondria slightly distorted myofibrils. CONCLUSION: EM investigation of extraocular muscles in CPEO and LHON reveals marked differences. A "mosaic-like" pattern caused by a selective damage of muscle fibres was evident in CPEO, whereas a diffuse increase in mitochondria with preservation of myofibrils characterised the LHON case. These ultrastructural changes may relate to the different expression of the two diseases, resulting in ophthalmoplegia in CPEO and normal eye movements in LHON.     

Late onset Leber''s optic neuropathy: a case confused with ischaemic optic neuropathy.

A case is reported of a 63-year-old man with progressive central visual loss in one eye followed 11 months later by involvement of the fellow eye. A diagnosis of chronic ischaemic optic neuropathy was considered. However, despite a negative family history, the absence of electrocardiographic abnormalities, and minimal fundus changes a diagnosis of Leber's optic neuropathy was made on the basis of magnetic resonance imaging findings and the mitochondrial DNA mutation at base pair 11778.