视路疾病患者脑功能性磁共振成像初步观察

目的 观察视路疾病患者视网膜拓扑投射的分布及脑功能性磁共振成像(fMRI)与视野检查结果的关系.方法 3例经病理检查确诊为垂体瘤和颅咽管瘤的鞍区占位患者(患者组)6只眼以及年龄24～30岁的3名健康志愿者纳入研究.患者组6只眼最佳矫正视力无光感～1.0;健康志愿者矫正视力1.0,除近视外无其他眼疾.受检者均无fMRI检查禁忌.常规行最佳矫正视力、直接和(或)间接检眼镜眼底检查,Octopus101电脑全自动视野计32程序策略趋势导向检查法行中心静态视野检查.fMRI检查采用GE signa VH/I 3.0T扫描机.视觉刺激占据12°视角,采用对比度接近100%的黑白棋盘格,背景为棋盘格的平均亮度,包括周期性扩张或收缩的环形刺激和顺时针或逆时针旋转的楔形刺激两种模式.功能图像采用梯度回波的平面同波序列的血氧水平依赖扫描序列,垂直于距状裂冠状位扫描,三维采集方式的扰相梯度回波序列矢状位采集高分辨率解剖结构数据.数据分析采用AFNI软件,并且应用Freesurfer进行皮层的分割、膨胀处理.结果 6只患眼中,视野颢侧缺损3只眼,颞上方缺损2只眼,不能完成检查1只眼.环形刺激的功能图像显示,枕叶视觉皮层产生了时相对应的激活图像,枕叶后极沿距状裂向前迁移对应黄斑中心区向周边视野的迁移.楔形刺激的功能图像显示,初级视觉皮层的极角拓扑投射的空间序列与视野相反.距状裂下方的视皮层主要对应对侧上方视野,距状裂上方主要对应对侧下方视野.刺激患眼不能诱导出与相应视野缺损相关的初级视觉皮层的激活,存在相应视觉皮层反应的减少.结论 fMRI检查结果与常规视野计检查的结果有很好的对应关系,可以反映视路疾病患者的视野缺损对应的皮层反应.     

视觉通路病变的视野判读要点

视觉通路的组成包括：视网膜、视神经、视交叉、视束、外侧膝状体、视放射及枕叶视觉中枢。视野检查是视觉通路疾病诊疗过程中不可或缺的重要辅助检查之一,用于早期发现视功能异常、鉴别视路疾病、了解疾病进展等。不同部位的损害可表现出不同形式的视野缺损,有些特征性的视野异常可帮助我们快速而准确地定位诊断。因此对视野检查结果的正确判读是神经眼科医师重要的基本技能之一。     

枕极脑梗死病变导致不典型视野缺损一例

后视路病变是视交叉以后的视觉通路其本身或毗邻结构发生病变，引起视觉功能改变的一类疾病。神经眼科医生比较熟悉枕叶病变引起的对称性同侧偏盲，但枕极(纹状皮质的最后部分)的病变产生中心性对称性同向盲点，此类视野改变容易被忽略或误诊。该文报道一例老年男性患者，因双眼视觉清晰度下降、视物变形就诊。眼科检查：最佳矫正视力：右眼0.8，左眼1.0,FM-100检查提示重度色觉异常，颅脑磁共振成像(magnetic resonance imaging,MRI)提示双侧枕叶脑梗死(右侧枕极部，左侧纹状皮质前部)，24-2 Humphrey视野检查可见双眼同向暗点趋势(不典型)，10-2 Humphrey视野检查可见双眼中心视野同向偏盲(暗点)，故而确诊。后视路病变可引起多种特征性的视野改变，可伴有高级视功能异常及其他神经系统症状和体征，是神经眼科的重要组成部分。该例枕极脑梗死病变产生对称性同向性盲点伴色觉改变患者的诊治过程，提示需关注后视路病变视野改变的多样性及其他视觉功能异常，提高早期诊断率，改善患者预后。     

枕叶脑卒中视觉诱发电位与脑血流量的关系

目的探讨枕叶脑卒中患者视觉诱发电位（VEP）和脑血流量的关系。方法对50例枕叶脑卒中患者和50例正常人进行视觉诱发电位（VEP）检查，同时测定脑血流量。结果脑卒中组VEP异常35例（70％），对照组异常4例（8％）。脑卒中组枕叶脑血流量平均42．7±6ml100（－1）／min，对照组49．6±7．6ml100（－1）／min，VEP异常与枕叶脑血流量呈负相关，伴有视野缺损VEP异常率高。结论VEP对诊断中枢损伤价值较大，尤其伴有视野缺损者意义尤大，VEP异常与枕叶脑血流量呈负相关。     

60例鞍区肿瘤对视器影响的临床分析

目的：分析鞍区肿瘤对视器影响的临床特点，探索仅有视觉改变的鞍区肿瘤患者的早期诊断。方法：回顾分析10年60例鞍区肿瘤患者的视力、视野、眼底、眼肌变化临床资料。 结果：视力不同程度障碍者110只眼，占91.7%；一眼或双眼颞侧偏盲40例，占83.3%；—眼或双眼视神经萎缩56例，占93.3%. 结论：视力障碍、视野缺损、视神经萎缩是鞍区肿瘤患者的主要视器表现；视野、CT及磁共振检查有利干早期确诊． （中华眼底病杂志，1996，12：124-125）     

斜视性弱视儿童大脑视皮层损害的脑磁图研究

目的探讨内斜视性弱视患者,在不同视野黑白棋盘格翻转刺激条件下,大脑皮层活动脑磁图的变化。方法单眼内斜视性弱视患者4名,分别进行双眼、单眼全视野刺激,单眼颞侧以及鼻侧视野刺激,记录视觉诱发磁场成份之一的M100的振幅、潜伏期以及源定位的变化情况,与4名正常对照组进行比较。结果双眼全视野刺激,内斜视性弱视组大脑皮层反应M100的振幅降低、潜伏期延长（P〈0.05）;弱视眼鼻侧视网膜M100的振幅比颞侧视网膜M100的振幅降低、潜伏期延长（P〈0.05）;非弱视眼M100的振幅比正常对照组M100的振幅降低,潜伏期延长（P〈0.05）;内斜视性弱视组弱视眼全视野刺激源定位的X轴与正常组比较更偏向原点（P〈0.05）。结论内斜视性弱视眼的鼻侧网膜存在一定程度和一定范围的抑制,源定位上弱视眼存在眼优势柱的偏移,斜视性弱视的非弱视眼与正常组也存在功能的差异。     

Octopus联合视野检查在枕叶病变中的应用

目的 了解不同枕叶病变的视野特点,并对比枕叶患者Octopus联合视野检查与Goldmann周边视野在枕叶疾病诊断中的应用价值.方法 回顾性分析2006年4月至2008年3月因影像学诊断提示有枕叶病变到我科就诊的54例(108眼)患者的临床资料,所有患者均行Octopus联合视野检查与Goldmann周边视野检查.结果 54例患者中肿瘤性病变27例,脑梗塞12例,血管性病变-动静脉畸形10例,炎症性病变5例.Goldmann周边视野与Octopus联合视野检查的吻合性:2种检查方法 检查的缺损类型相符率达81.48%(44例),5.56%(3例)的患者中Octopus联合视野检查能发现更小的缺损.7.74%(4例)的患者采用Goldmann周边视野具有更好的可靠性.结论 枕叶病变视野缺损与不同疾病对视皮质的占位效应相关.自动视野计联合视野检查可用于枕叶疾病的诊断.     

儿童全视野和半视野视觉诱发电位的研究

目的：对正常儿童和弱视儿童分别进行全视野和半视野棋盘格翻转刺激，观察视觉诱发电位（VEP）P100峰的潜伏期，进行有关视通路的方法。方法：使用MVT视觉图形信号发生器和MVT16导视觉诱发电位仪在11个空间频率下对10例视力正常的7－8岁儿童和5例4－6岁弱视儿童进行半视野和全视野的棋盘格翻转刺激并记录VEP反应。结果：（1）对正常儿童进行半视野刺激时，与刺激同侧的半球上电极测得的P100峰潜伏期比异侧要提前；（2）正常儿童与弱视儿童的第14导电极（Oz，位于枕部正中）测得的P100峰潜伏期与刺激野（指半视野或全视野，同侧视野）无明显关系；（3）弱视儿童的P100峰潜伏期较正常儿童有明显延迟。结论：弱视儿童视觉传导通道障碍，视觉中枢存在发展和功能异常，VEP是检测弱视儿童视功能的客观方法。     

功能核磁技术对常规影像学检查正常的后视路疾病的诊断两例

后视路疾病是神经眼科疾病的重要组成部分,是指当颅脑血管疾病、肿瘤、外伤等累及视柬、外侧膝状体、视放射及枕叶视觉中枢引起视功能改变的一类疾病,临床症状多不典型后税路疾病患者多伴行视野缺损、视力下降,但眼底检食多正常．部分患者行颅脑MRI或CT检查也术见异常。     

单眼挫伤瞳孔对光反射与视功能改变的相关研究

目的：测量单眼挫伤患者瞳孔对光反射的改变，分析瞳孔对光反射与眼挫伤后其他视功能评价方法的相关性。方法：使用红外线自动瞳孔仪分别检测26例单眼挫伤患者双眼瞳孔对光反射，并行视力、视野、图形视觉诱发电位等视功能检查。检查的瞳孔对光反射参数包括瞳孔面积，对光反应潜伏期、反应幅度。结果：眼挫伤患者健眼直接、间接反应幅度比与双眼视力差具有显著相关性（r=-0．648）；瞳孔对光反应幅度差、反应幅度比均与视野平均偏差具有显著相关性（r=0．5和r-0．535）；瞳孔对光反应幅度比与双眼视觉诱发电位振幅比具有显著相关性；多重线性回归分析显示瞳孔对光反应幅度和VEP振幅结合可提高预测视力预后的可能性。结论：在瞳孔对光反射各参数中，瞳孔对光反应幅度在反映眼挫伤后视功能改变方面优于其它参数，眼挫伤患者瞳孔对光反应幅度与视力、视野、VEP波幅具有中度相关性，其与VEP联合应用可提高眼挫伤后准确预测视功能的可能性。     

Automated perimetry and neuro-ophthalmology. Topographic correlation

Visual fields continue to be a key exploration for the diagnosis and follow-up of patients in neuro-ophthalmology. The pattern of visual field defects helps, and in many cases allows, the identification of brain damage location. Manual kinetic perimetry has been replaced by automated methods. 24-2 SITA (Humphrey Visual Field Analyser) and TOP (Octopus) are regarded as the standard perimetric explorations in neuro-ophthalmology. Goldmann perimetry remains as an useful exploration for temporal crescent detection in occipital lobe diseases, and it could be more accurate and consistent for studying lesions in the post-geniculate pathway. Frequency doubling perimetry could be useful for detecting neuro-ophthalmic visual field defects, but does not provide an accurate characterisation of the lesions. From the neuro-ophthalmic point of view, visual field defects could be divided in pre-chiasmatics, chiasmatics and post-chiasmatics. Pre-chiasmatic defects are strictly unilateral, do not respect the vertical meridian, often have a nasal step associated and are usually accompanied by ocular pathology detectable in an ophthalmic examination. The characteristic perimetric pattern of chiasmal disease is bi-temporal hemianopsia. Homonymous contralateral defects are the characteristic perimetric pattern of post-chiasmal disease, and their congruency increases when the lesions are closer to the occipital lobe. Neuroimage studies are mandatory in all patients with a perimetric defect pattern compatible with chiasmal or post-chiasmal lesions. Magnetic Resonance Imaging may be normal in a patient with homonymous defects in Alzheimer's disease, the Heidenhain variant of Creutzfeldt-Jakobs disease, carbon monoxide poisoning and mild occipital ischemia demonstrated by SPECT or PET imaging (Arch Soc Esp Oftalmol 2002; 77: 413-428).     

Functional magnetic resonance imaging of visual cortex in a patient with cerebrovascular insufficiency

We compare the findings of functional magnetic resonance imaging (MRI) of the visual cortex in a patient with moyamoya disease with other neuro-imaging techniques. Automated static perimetry demonstrated a slight depression of the left visual field in both eyes. MRI of the brain showed diffuse atrophy of the right cerebral hemisphere, sparing the occipital lobe. Single-photon emission computed tomography showed relatively preserved perfusion to the right occipital lobe. Functional MRI during visual stimulation, however, demonstrated an apparent lack of activation of the right primary visual cortex, which did not correlate with the known retinotopic map of the visual cortex. The patient seems to have had a lack of reserved ability to respond to visual stimuli with maximal autoregulatory vasodilatation in the visual cortex, even though apparent morphologic change and dense visual field defects had not been observed.     

A comparison of tangent screen, goldmann, and humphrey perimetry in the detection and localization of occipital lesions

OBJECTIVE: To compare manual kinetic perimetry with tangent screen and Goldmann techniques and automated static perimetry with the Humphrey Field Analyzer in the detection and localization of occipital lobe lesions. DESIGN: Prospective consecutive comparative case series. PARTICIPANTS: Twelve patients with well-defined occipital lobe infarcts on magnetic resonance (MR) imaging were studied. MAIN OUTCOME MEASURES: The patients were tested by tangent screen, Goldmann, and Humphrey perimetry (central 30-2 threshold program). The three visual fields were compared and correlated with MR images. RESULTS: All three perimetric techniques detected the presence of postchiasmal lesions. However, localization of lesions differed with perimetric technique. Visual fields obtained from tangent screen and Goldmann perimetry were similar and corresponded well with the location of lesions on MR images in all 12 patients. Humphrey perimetry inaccurately localized the lesion to the proximal part of the postchiasmal pathway by revealing incongruous fields in two patients, failed to detect sparing of the posterior occipital cortex or occipital pole in four patients, and estimated a larger extent of damage in one patient when compared with MR images and manual perimetry. CONCLUSIONS: All three perimetric techniques are satisfactory screening tests to detect occipital lesions. However, tangent screen and Goldmann perimetry provide information about the location and extent of lesions that is more consistent with prevailing knowledge of the effects of the lesion in the postgeniculate visual pathway.     

Progressive shrinkage of the visual field during automated perimetry following traumatic brain injury Patients’ experience

Purpose: To establish a distinction between the visual field and the attentional field in patients with traumatic brain injury, and to elucidate the patients’ experience with attentional field defects. Methods: We retrospectively reviewed the clinical observations of 25 traumatic brain-injury patients. On the basis of the 30-degree visual field printout, we identified six patients with concentric contraction and analyzed their visual fields by comparing the two consecutive stages of the Octopus N1 screening and threshold program. The recorded fields were compared with the results of clinical confrontational field testing. Three of the six patients had been asked to describe their experience during automated perimetric evaluation. Results: The visual fields showed various degrees of contraction, some severe. All six showed progressive shrinking of the field during the perimetric evaluation procedure. However, no defects were apparent with confrontational field testing. False-negative catch trials ranged from 0 to 50% (mean 18.1%). When asked, the three patients had all described a striking progressive darkening of the background and shrinkage of the visual field during the automated perimetric examination. Conclusions: During automated perimetry, patients with traumatic brain injury may develop mild to severe concentric contraction, which is progressive over time. This is associated with the experience of dramatic obscuration of the visual field. This may reflect an organic disturbance in attentional mechanisms, revealed when executing dual task demands. When analyzing results from automated perimetry in such patients, a distinction should be made between visual and attentional fields.     

Visual Field Characteristics in East Asian Patients With Occult Macular Dystrophy (Miyake Disease): EAOMD Report No. 3

PurposeThe purpose of this study was to investigate the perimetric features and their associations with structural and functional features in patients with RP1L1-associated occult macular dystrophy (OMD; i.e. Miyake disease).MethodsIn this international, multicenter, retrospective cohort study, 76 eyes of 38 patients from an East Asian cohort of patients with RP1L1-associated OMD were recruited. Visual field tests were performed using standard automated perimetry, and the patients were classified into three perimetric groups based on the visual field findings: central scotoma, other scotoma (e.g. paracentral scotoma), and no scotoma. The association of the structural and functional findings with the perimetric findings was evaluated.ResultsFifty-four eyes (71.1%) showed central scotoma, 14 (18.4%) had other scotomata, and 8 (10.5%) had no scotoma. Central scotoma was mostly noted in both eyes (96.3%) and within the central 10 degrees (90.7%). Among the three perimetric groups, there were significant differences in visual symptoms, best-corrected visual acuity (BCVA), and structural phenotypes (i.e. severity of photoreceptor changes). The central scotoma group showed worse BCVA often with severe structural abnormalities (96.3%) and a pathogenic variant of p.R45W (72.2%). The multifocal electroretinogram (mfERG) groups largely corresponded with the perimetric groups; however, 8 (10.5%) of 76 eyes showed mfERG abnormalities preceding typical central scotoma.ConclusionsThe patterns of scotoma with different clinical severity were first identified in occult macular dystrophy, and central scotoma, a severe pattern, was most frequently observed. These perimetric patterns were associated with the severity of BCVA, structural phenotypes, genotype, and objective functional characteristics which may precede in some cases.     

后部视路疾病诊治中的几个问题

脑血管疾病、脑肿瘤及脑外伤所导致的后视路疾病在临床上很常见,多表现为同侧偏盲或象限性盲,在国内眼科界对这类疾病的眼部表现缺乏应有的重视。弥散张量成像（diffusion tenser imaging,DTI）、功能磁共振成像（functional magnetic resonance imaging,fMRI）等影像学新技术的出现为后视路疾病的诊断提供了新的工具。对后视路疾病患者除了必要的手术治疗外,早期给予药物干预,减少原发及继发性视路损伤,稳定期给予视觉康复治疗,从而在最大程度上改善这类患者的视觉质量。     

BOLD fMRI and DTI in strabismic amblyopes following occlusion therapy

Evaluation of brain cluster activation using the functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) was sought in strabismic amblyopes. In this hospital-based case–control cross-sectional study, fMRI and DTI were conducted in strabismic amblyopes before initiation of any therapy and after visual recovery following the administration of occlusion therapy. FMRI was performed in 10 strabismic amblyopic subjects (baseline group) and in 5 left strabismic amblyopic children post-occlusion therapy after two-line visual improvement. Ten age-matched healthy children with right ocular dominance formed control group. Structural and functional MRI was carried out on 1.5T MR scanner. The visual task consisted of 8 Hz flickering checkerboard with red dot and occasional green dot. Blood-oxygen-level-dependent (BOLD) fMRI was analyzed using statistical parametric mapping and DTI on NordicIce (NordicNeuroLab) softwares. Reduced occipital activation was elicited when viewing with the amblyopic eye in amblyopes. An ‘ipsilateral to viewing eye’ pattern of calcarine BOLD activation was observed in controls and left amblyopes. Activation of cortical areas associated with visual processing differed in relation to the viewing eye. Following visual recovery on occlusion therapy, enhanced activity in bilateral hemispheres in striate as well as extrastriate regions when viewing with either eye was seen. Improvement in visual acuity following occlusion therapy correlates with hemodynamic activity in amblyopes.     

The representation of the visual field in the occipital striate cortex

The traditional Holmes’ view of the representation of the visual field in the occipital striate cortex was universally accepted for most of the last century.However, following the advent of detailed brain imaging, a reappraisal has taken place during the past decade. In particular, Horton and Hoyt have proposed a revised representation hypothesis with an increased representation of the central 10°. Nevertheless, controversies remain concerning firstly, the precise representation of the entire visual field throughout the occipital striate cortex, and secondly, the representation of macular or foveal vision (unilateral or bilateral). These issues have been addressed through experimental studies in non-human primates, clinical lesional studies in humans with correlation of perimetric deficits to brain-imaging abnormalities, and functional imaging studies in healthy volunteers. Recently, more sophisticated perimetric techniques with monitoring of fixational eye movements have allowed more detailed understanding of the macular/foveal representation in humans. An historical review will be contrasted with current concepts and compared with recent functional imaging studies.     

Occipital lobe dysfunction revealed by functional brain imaging in a patient with traumatic visual field loss

We report a patient with visual field loss due to closed head trauma who was imaged with anatomic and functional brain imaging. The findings of ophthalmologic examination were normal except for a complete homonymous hemianopia on the right, an incongruous homonymous hemianopia on the left, and right oculomotor palsy. The results of anatomic brain imaging, computed tomography, and magnetic resonance imaging (MRI) were unremarkable. However, single-photon emission computed tomography (SPECT) scan revealed marked hypoperfusion of the left occipital lobe and functional MRI showed a corresponding strikingly reduced response to visual stimuli in the left occipital lobe. Therefore, this patient is thought to have had dysfunction of the left occipital lobe. Functional brain imaging techniques, such as SPECT and functional MRI, can be helpful in the localization of the responsible lesions even when conventional neuro-imagings are nondiagnostic.     

脑外伤致视功能损伤20例临床分析

目的分析脑外伤致视功能损伤的原因、临床表现，为临床诊治提供参考。方法回顾性分析5年来因脑外伤致视功能损伤患者的致伤原因、临床表现及诊断要点。结果20例视功能损伤患者中，男15例、女5例；年龄5～70岁。其中青壮年16例。致伤原因：交通事故12例、跌落伤4例、打架斗殴伤3例、脑外科手术后1例。13例有外伤后意识丧失。视功能损伤包括：视力下降或丧失16例（20眼）、视野损伤7例（8眼）、复视3例。结论脑外伤特别是有意识丧失的患者，应及时进行眼科检查，以得到及时诊断和治疗。