重视光相干断层扫描技术在神经眼科中的应用

光相干断层扫描技术以能够观察发现轻微视盘水肿、光感受器内外节连接层改变,测量视盘周围平均视网膜神经纤维层厚度、视网膜厚度、黄斑容积,检测轴索丢失、黄斑区神经节细胞复合层损害等独特优势,在青光眼和非青光眼性视神经病变、视神经疾病和黄斑疾病、外层和内层视网膜病变的诊断与鉴别诊断,评价神经眼科疾病疗效、随访观察及评估疾病预后以及神经眼科疾病发病机制研究等方面均表现出重要的应用价值和广泛的应用前景.值得广大神经眼科医生深入了解、重视和应用.     

MRI技术在眼病临床及科学研究中的应用

随着医学影像学的发展,磁共振成像(MRI)技术凭借着无创、成像清晰、对软组织具有高分辨率的特点逐渐运用到眼科疾病及相关动物模型的研究领域中。MRI在眼科最主要应用在眼眶、眼肿瘤疾病,近年来,MRI也逐渐应用于视觉损伤的临床及科学研究中。下面简单介绍MRI在屈光不正、白内障、青光眼、弱视、视神经、脉络膜疾病、视网膜病变等眼病及眼科科研领域中的应用。     

我国视觉生理近五年研究进展

视觉生理学的主要任务是阐明视觉产生的神经机制,视觉的接受过程以视神经细胞膜电化学变化和动作电位沿神经细胞轴索传递为特征.通过使用视觉刺激仪,表面电极和放大记录装置可以观测到视觉器官在视觉接受过程中的生物电活动情况.临床视觉电生理检查已成为眼科临床检查的重要手段之一,提供了从视网膜至视皮层无创伤性的、客观的、定量的、定位的视功能测试方法.近5年来我国视觉生理学的基础研究和临床应用取得了显著的发展.     

2007年神经眼科学习班将在北京举办

吴阶平医学基金会、解放军总医院眼科联合举办的“神经眼科学习班”，将于2007年5月11日至5月13日在北京由中国人民解放军总医院举办。学习班将邀请国内知名专家及中青年医师授课。授课主要内容：（1）神经眼科学的基础知识；（2）视野检测方法；（3）神经眼科学的基本检查法；（4）常见的神经眼科学疾病：颅内静脉窦血栓形成与视乳头水肿、颈内动脉狭窄与相关眼病、蝶鞍区病变与眼科表现、糖尿病视神经病变、视神经炎的诊治、旁中心视力与视神经炎的关系、缺血性视神经病变、外伤性视神经病变诊治的新观点、Leber视神经病、视网膜动脉阻塞、视交叉疾患、有神经眼科意义的眼眶疾病；     

斑马鱼视觉损伤和视神经再生的研究进展

斑马鱼因其视觉系统与人类的相似性和其视网膜再生的巨大潜能,成为目前研究眼变性疾病的热门模型。眼变性疾病特别是视网膜变性、视神经变性会严重影响视力,并且病变后再生修复十分有限,严重者甚至导致失明。与哺乳动物相反,斑马鱼能修复视神经轴突损伤,刺激视网膜Müller胶质细胞去分化为多能祖细胞,从而实现视网膜神经元及神经轴突再生,恢复正常视功能。本文主要从斑马鱼模型在眼病方面的应用,斑马鱼视网膜神经元和Müller胶质细胞响应损伤启动再生修复的关键信号通路方面作一综述。     

《罗兰视觉电生理仪测试方法和临床应用图谱学》一书出版

由中山大学中山眼科中心视觉电生理专家吴德正教授与北京同仁眼科中心刘妍博士主编的《罗兰视觉电生理仪测试方法和临床应用图谱学》一书已由北京科学技术出版社出版。该书通过电生理图形、眼底图片等方式，详细阐述了视觉电生理的临床应用，内容涉及临床上与视觉电生理有关的许多疾病；介绍了罗兰视觉电生理仪的各项测试项目（包括全视野视网膜电图、多焦视网膜电图、视诱发电位及眼电图等）的刺激参数选择、记录条件、结果分析及打印方法；[第一段]     

图像反转视觉诱发电位(第二部分:关于临床应用问题)

图像反转视觉诱发电位(VEPP)对于许多眼科和与眼科有关的疾病的诊断与鉴别诊断、病程确定、预后及疗效估计有着特殊的作用,如青光眼、各种原因的视神经病变、黄斑疾病、视网膜血液循环障碍、弱视、功能性或器质性视觉障碍的客观判断等。其在临床工作中的重要性正日益体现出来。本文拟在对正常人眼所行的VEPP分析的基础上,对该检查方法的临床应用问题进行一些讨论,以和     

经角膜电刺激在视网膜疾病治疗中的研究进展

近年来,眼部电流刺激(electrical stimulation,ES)在不同方向的研究中逐渐揭示了其在多种视网膜疾病中的潜在治疗价值。其中,经角膜电刺激(transcorneal electrical stimulation,TES)作为一种非侵入性的治疗方法,能对视网膜、视神经、眼底血管及其相关结构产生积极的影响。TES能够改善视力,在保护感光细胞和减缓疾病进展方面显示出积极效果,提高患者的生存质量,还能够在不损伤眼球的情况下调节大脑中的神经元活动,为视网膜疾病的治疗提供一种新的选择。该文对近年来TES在视网膜色素变性(retinitis pigmentosa,RP)、年龄相关性黄斑变性(age-related macular degeneration,AMD)、视网膜血管病、青光眼以及视神经病变等疾病中的应用研究进行了综述。研究发现,TES治疗是一种安全且无需手术的辅助治疗工具,具有广泛的应用前景。该文旨在为临床医师提供一个全面的TES研究概述,并深入探讨其在眼科学领域的潜在应用价值。然而,TES治疗的具体机制仍需进一步探讨,以便更好地应用于临床实践。同时,未来研究还应关注TE...     

2007年军队继续医学教育神经眼科学习班招生通知

吴阶平医学基金会、解放军总医院眼科联合举办的“神经眼科学习班”,将于2007年5月11~13日在北京市中国人民解放军总医院举办。学习班将邀请国内知名专家及近年来活跃的中青年医生授课。授课主要内容:(1)神经眼科学的基础知识。(2)视野。(3)神经眼科学的基本检查法。(4)常见的神经眼科学疾病:颅内静脉窦血栓形成与视乳头水肿、颈内动脉狭窄与相关眼病、蝶鞍区病变与眼科表现、糖尿病视神经病变、视神经炎的诊治、旁中心视力与视神经炎的关系、缺血性视神经病变、外伤性视神经病变的诊治新观点、Leber视神经病、视网膜动脉阻塞、视交叉、有…     

视觉诱发电位在眼科学中的临床应用价值——Christchurch医院的经验

目的 探讨视觉诱发电位在眼科临床中的应用价值.方法 总结Christchurch医院30年来视觉诱发电位在临床应用的经验.结果 视神经炎是视神经的炎症病变,表现为单眼的突发性失明并伴随眼球移动时疼痛.视神经炎的电生理表现为视觉诱发电位的潜伏期延长,这种延长在发病3周视力恢复后仍存在.由于视神经炎关系到多发性硬化症的并发,对其正确的鉴别诊断十分重要.视神经诱发电位一个重要的临床应用,是能发现已痊愈的视神经炎的电位异常.在视觉诱发电位中,P100潜伏期的延长可从急性期延迟很长时间,它在占位性视神经疾病的诊断中有重要的诊断价值,也可作为视交叉占位性病变的确诊手段.另外,视觉诱发电位在功能性失明或装盲(尤其是儿童)有重要应用价值.结论 视觉电生理在眼科临床中的应用应得到肯定.(中国眼耳鼻喉科杂志,2007,775～78)     

Retinal prosthesis for the blind

Most of current concepts for a visual prosthesis are based on neuronal electrical stimulation at different locations along the visual pathways within the central nervous system. The different designs of visual prostheses are named according to their locations (i.e., cortical, optic nerve, subretinal, and epiretinal). Visual loss caused by outer retinal degeneration in diseases such as retinitis pigmentosa or age-related macular degeneration can be reversed by electrical stimulation of the retina or the optic nerve (retinal or optic nerve prostheses, respectively). On the other hand, visual loss caused by inner or whole thickness retinal diseases, eye loss, optic nerve diseases (tumors, ischemia, inflammatory processes etc.), or diseases of the central nervous system (not including diseases of the primary and secondary visual cortices) can be reversed by a cortical visual prosthesis. The intent of this article is to provide an overview of current and future concepts of retinal and optic nerve prostheses. This article will begin with general considerations that are related to all or most of visual prostheses and then concentrate on the retinal and optic nerve designs. The authors believe that the field has grown beyond the scope of a single article so cortical prostheses will be described only because of their direct effect on the concept and technical development of the other prostheses, and this will be done in a more general and historic perspective.     

Advances in the development of visual prostheses

Visual prostheses are based on neuronal electrical stimulation at different locations along the visual pathway (ie, cortical, optic nerve, epiretinal, subretinal). In terms of retinal prostheses, advances in microtechnology have allowed for the development of sophisticated, high-density integrated circuit devices that may be implanted either in the subretinal or epiretinal space. Analogous to the cochlear implants for some forms of deafness, these devices could restore useful vision by converting visual information into patterns of electrical stimulation that would excite the remaining spared inner retinal neurons in patients with diseases such as retinitis pigmentosa and age-related macular degeneration. The different types of implants and recent results are discussed, but special emphasis is given to retinal implants.     

Neuroprotective effect of transcorneal electrical stimulation on the acute phase of optic nerve injury

PURPOSE: Traumatic optic neuropathy often induces a loss of vision that proceeds rapidly within several hours, together with retinal ganglion cell death, in a much slower time course. Electrical stimulation has previously been shown to rescue injured retinal ganglion cells from cell death. The present study tests whether transcorneal electrical stimulation could preserve visual function after an optic nerve crush. METHODS: Transcorneal electrical stimulation was given immediately after a calibrated optic nerve crush. We measured visually evoked potentials (VEPs) in the visual cortex of rats before and immediately after the optic nerve crush and after the transcorneal stimulation to estimate an extent of damage and effects of stimulation in individual animals. In addition, the retinal axons were labeled with a fluorescent anterograde tracer to determine whether the transcorneal electrical stimulation can protect the retinal axons from degeneration. RESULTS: The optic nerve crush was made at an intensity that does not allow a spontaneous recovery of VEP for 1 week. The transcorneal stimulation immediately increased VEP amplitude impaired by the optic nerve crush, and this augmentation was often preserved after 1 week. In the stimulated animals, a larger amount of retinal axons projected centrally beyond the crushed region in comparison to the unstimulated animals. CONCLUSIONS: Transcorneal electrical stimulation would restore the functional impairment of optic nerve by traumatic injury at a very early stage and protect retinal axons from the ensuing degeneration.     

Elektrostimulation des visuellen Systems Von therapeutischer Empirie zur Entwicklung von Sehprothesen

The investigation of the influence of electrical stimulation on the visual system can be sub-divided into empirical, diagnostic and therapeutic phases of development. The first electrical stimulations of the visual system in animals dating back to the eighteenth century represent empirical approaches well before knowledge on the principles of bioelectrical nerve activity was available. Despite this lack of understanding, attempts were made at that time to treat blind people by electrical stimulation. More than 100 years later, with the advancement of technology and knowledge on nerve function, attempts were made to establish various methods of electrical stimulation for the diagnosis of different diseases of the visual system. For more than 30 years attempts to develop electrical devices have been made to by-pass defects of the visual system and to restore basic orientation. Presently nine different groups world-wide are focusing on retinal, optic or cortical implants. A short review on the historical use of electrical stimulation and new therapeutical attempts are given in this paper.     

Response properties of electrically evoked potential elicited by multi-channel penetrative optic nerve stimulation in rabbits

Visual prosthesis is a potential way to restore partial vision for the patients with degenerative retinal diseases such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD). Optic nerve stimulation with penetrating microelectrode array has been suggested as a possible method for visual prosthesis. The purpose of this study was to investigate the feasibility and basic response properties of cortical responses elicited by optic nerve stimulation with penetrating electrodes in rabbits. In this study, three triangularly or linearly configured platinum–iridium wire electrodes were inserted into the optic nerves of rabbits for electrical stimulation. The charge-balanced current pulses with amplitudes ranging from 10 to 100 μA at 0.5 ms pulse duration were used as the electrical stimuli. The electrically evoked potentials (EEPs) were recorded with a 16-channel silver-ball electrode array in the rabbit visual cortex. Our experimental results showed that the activities of visual cortex could be effectively evoked by the optic nerve stimulation with penetrating electrodes. The threshold of current and charge density to elicit EEPs under optic nerve stimulation at 0.5 ms pulse duration was 20.3 ± 7.5 μA and 37.8 ± 13.9 μC/cm², respectively. Current stimuli with cathode-first pulses elicited larger cortical responses than that with anode-first pulses. The amplitude of P1 and extent of EEPs increased as the stimulating current amplitude increased, while the latency of P1 decreased. The spatial distributions of multi-channel EEPs in visual cortex demonstrated distinctively different properties under stimulation with different orientations of the stimulating electrodes. Changsi Cai and Liming Li contributed equally to this work.     

Transkorneale Elektrostimulation

Stimulation with weak electrical currents as a potential therapy for ophthalmic diseases has been propagated for a long time and encountered mixed acceptance but has recently regained interest due to observations in retinal implant projects. In these projects involving patients with retinitis pigmentosa a neuroprotective effect of weak, even subthreshold, electrical stimulation was found which led to improvement in visual functions even in areas distant from the implant. Results of several animal studies clearly substantiate a neuroprotective effect in degenerative retinal diseases and traumatic optic neuropathies. Studies in patients have so far been published for nonarteritic anterior ischemic and traumatic optic neuropathy, retinal artery occlusion and Stargardt's disease. These studies were mostly small and of short duration so that effects did not reach statistical significance. A controlled, randomized study in patients with retinitis pigmentosa has recently been published where positive tendencies and several statistically significant improvements in visual function were observed in one subgroup. Electrical stimulation further deserves further attention as several companies currently offer devices which should enable patients to self-administer electrical stimulation. This article gives an overview of the scientific background of electrical stimulation and critically assesses data from animal and human studies with focus on retinitis pigmentosa.     

角膜电刺激对糖尿病大鼠前部缺血性视神经病变模型的影响

观察并评估角膜电刺激对糖尿病大鼠前部缺血性视神经病变（AION）模型的影响。方法：实验 研究。健康雄性Sparague-Dawley大鼠40只，随机分组后抽出8只作为正常大鼠组。余下32只先予 以链脲佐菌素腹腔注射建立糖尿病大鼠模型，将造模成功的大鼠随机抽出8只作为糖尿病组，余下 24只糖尿病大鼠采用孟加拉玫瑰红联合532 nm激光方法建立AION大鼠模型。将24只造模成功的 AION大鼠随机分成3组，每组8只，分别为AION模型组，不予任何处理；电刺激组，予以角膜电刺 激（刺激参数为：电流1 mA，频率20 Hz，波宽1 ms/phase，刺激时间1 h，隔日1次，刺激2周）；假电 刺激组，电极安放位置与电刺激组相同，仅不接通电源。2周后5组大鼠进行眼底照相、光学相干断 层扫描和视觉诱发电位，然后处死，行视网膜及视神经冰冻切片，苏木精伊红染色观察。数据采用 单因素方差分析和LSD-t检验进行分析。结果：正常大鼠组视盘上半部视网膜厚度为（211±13）μm， 糖尿病大鼠组为（206±16）μm，AION模型组为（240±54）μm，假电刺激组为（216±11）μm，电刺 激组为（198±4）μm，5组视盘上半部视网膜厚度差异有统计学意义（F=2.854，P=0.038）。其中AION 模型组视盘上半部视网膜厚度高于正常组、糖尿病组、电刺激组，差异均有统计学意义（P<0.05）； 正常组与糖尿病组差异无统计学意义，AION模型组与假电刺激组未见明显差异。视觉诱发电位示 AION模型组N1潜伏期较电刺激组延长，差异有统计学意义（t=4.1，P<0.001）；AION模型组P1潜伏 期较正常组、糖尿病组、假电刺激组、电刺激组延长，差异均有统计学意义（t=4.1、2.5、2.6、3.2， P<0.05）；电刺激组N1-P1波幅大于假电刺激组，差异有统计学意义（t=4.0，P<0.001）。结论：角膜电 刺激能促进糖尿病大鼠前部缺血性视神经病变模型肿胀的视盘变薄，加速视盘水肿的消退，同时在 一定程度上改善视功能。     

Visual electrophysiology in the clinical evaluation of optic neuritis,chiasmal tumours,achiasmia, and ocular albinism: an overview

Background and Methods In routine clinical evaluation of optic neuritis and chiasmal tumours, pattern electroretinography and visual evoked potentials (VEPs) to pattern-reversal stimulation are useful examinations. Similarly, in achiasmia and ocular albinism, VEPs to flash and pattern-onset stimulation provide relevant information. Results The role of visual electrophysiology in these diseases is to assess potential dysfunction of the visual pathway: (a) at the acute stage of optic neuritis, to determine the magnitude of conduction block of the optic nerve fibres; (b) at the clinical recovery stage of optic neuritis, to determine optic nerve conduction delay due to demyelination, and to follow possible remyelination; (c) at the recovery of optic neuritis when visual acuity does not normalise, to define loss of optic nerve fibres and retrograde degeneration of retinal ganglion cells; (d) in tumours at the chiasm, to detect abnormal conduction along the crossed and/or uncrossed fibres; and (e) in achiasmia or albinism, which are both congenital disorders associated with nystagmus, to detect achiasmia and absence of or reduced optic nerve fibre decussation at the chiasm, or to detect ocular albinism and excess of optic nerve fibre decussation at the chiasm. In optic neuritis, two recent examinations have been used to detect retrograde axonal degeneration: photopic negative response of the electroretinogram, to assess dysfunction of ganglion cell axons; and optic coherence tomography, to measure thinning of the retinal nerve fibre layer. In optic neuritis, multifocal VEPs provide a promising clinical examination, because this can show areas that are associated with normal or abnormal optic nerve fibre function. Conclusions Visual electrophysiology defines function of the visual pathway and is relevant: (1) in optic neuritis, when visual acuity does not recover well; (2) in tumours of the chiasm with normal visual fields, as in paediatric patients who cannot adequately perform perimetry; and (3) in children with congenital nystagmus and suspected achiasmia or ocular albinism.     

青光眼的视觉通路损伤及损伤后视觉系统的神经可塑性研究进展

青光眼是一组以进行性视神经萎缩和视野缺损为共同特征的疾病。近来研究表明青光眼的病理损伤不仅局限于视网膜及视神经,而是累及整个视觉通路。近年研究发现神经系统损伤并非传统认为的完全不可逆,而是具有一定的可塑性,也有研究表明青光眼的视觉通路的神经元在一定条件刺激下,可能进行修复及重塑,从而恢复一定的视觉功能,这为青光眼的治疗提供了新的思路及方向。