正常人视觉皮层视网膜拓扑投射的功能磁共振研究

目的研究功能磁共振（fMRI）检测正常人视觉皮层的视网膜拓扑投射分布特征,探讨功能定位的V1／V2边界的解剖特征。方法以3名健康志愿者作为实验对象,年龄25～30岁,右利手。视觉刺激占据12度视角,采用对比度接近100％的棋盘格,背景为黑白棋盘格的平均亮度,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。应用GE Signa VH/I 3．0 T fMRI扫描机。功能图像采用GRE-EPI的BOLD扫描序列,垂直于距状裂冠状位扫描,3D-SPGR序列矢状位采集高分辨率解剖结构数据。采用AFNI软件进行数据分析,应用Freesurfer软件进行皮层的分割、膨胀及切开展平处理。结果（1）环状刺激自中心向周边扩张时,视皮质枕叶后极至距状裂前部先后兴奋,并存在皮层放大效应;（2）楔形刺激揭示V1区的极角坐标方向与视野相反,相邻功能区的极角坐标方向相反;（3）功能定位的V1／V2边界位于脑回顶部附近。结论时相编码的视觉刺激是获得视觉皮层视网膜拓扑投射的有效手段,功能定位V1／V2边界的解剖特征支持了白质纤维最优化连接假说。     

视觉刺激功能磁共振成像在枕叶病变患者中的初步应用

目的 观察枕叶病变患者患侧与健侧的功能磁共振成像（fMRI）特点，评价fMRI在视觉中枢功能性病变检查、枕叶肿瘤定位、手术入路选择以及切除范围方面的临床应用价值。设计 病例系列。研究对象 伴有同侧偏盲的视觉中枢功能性病变及单侧枕叶肿瘤患者各1例。方法 对上述2例患者应用自行设计的双眼棋盘格刺激（5Hz）行脑fMRI检查。所得数据应用SPM软件处理（P〈0．01），与Goldmann视野计检查结果相比较，验证视野损害与其大脑皮层投影改变的一致性。主要指标 统计参数图，脑激活图，激活脑区信号变化的时间曲线，与标准化T1像叠加的脑激活图。结果 在视觉刺激on时，枕叶视功能区激活；off时无信号；2例患者fMRI检查右侧视功能区激活明确，左侧视功能区无信号与视野检查双眼右半视野缺损相一致。结论 视觉刺激程序能够很好地引出视觉中枢fMRI；fMRI的检查结果与视野结果一致性较好；fMRI在视觉中枢功能性检查、枕叶肿瘤范围定位的确定方面有良好的临床应用前景。     

多焦视诱发电位地形图

目的阐明多焦视诱发电位成分是如何从多通道双极记录中得出和进行地形学分析的.并研究不同的视皮层记录位置对多焦视诱发电位的波形、潜伏期(ms)和振幅(mV)的影响.方法采用多通道罗兰电生理系统(Retiscan,Wiesbaden/Brandenburg,Germany)分别测量50位正常人双眼不同视野的多焦视诱发电位(visual evoked potential,VEP)(最大的离心率为30°).两眼分别给予刺激.伪随机改变的刺激由多通道罗兰系统产生.刺激图形由60个刺激扇形组成,每个扇形又含16个方格,8个白色方格(＞130 cd/m2)和8个黑色方格(＜2 cd/m2).各个刺激单元的刺激翻转由一个伪随机序列控制.电极放置参照双极枕叶电极放置法,同时从4个前-后矢状中线及4个水平连线(横贯枕叶视皮层)上的皮肤电极上记录视觉诱发电位波形.上述电极可以是正极或负极.结果在记录的枕叶皮层区,不同记录通道所记录的VEP显示了不同的平均峰潜伏期和振幅值.在矢状中线上记录到的mVEP,其最大振幅值小于水平线上的记录值.另外,刺激视网膜不同部位所诱发的电位在头皮的位置是不同的.结论双极枕叶电极在矢状中线上记录到的mVEP与视野地形图记录的有良好的相关性.双极记录位置负极在枕骨粗隆,而正极在枕骨粗隆矢状轴上2 cm或4cm或正极在枕骨粗隆水平左、右4 cm时,记录得到的VEP结果更具可比性.为了更准确地评估客观视野缺损,可进行上下1/2或者水平1/2的多焦VEP记录.     

急性视神经炎的功能磁共振成像研究

目的应用功能磁共振成像技术探讨急性视神经炎的皮层功能变化。方法以1.5T磁共振成像系统采集14例单眼急性视神经炎、12例正常人视皮层BOLD-fMRI数据,比较正常组与视神经炎组两眼分别刺激时的视皮层激活像素数与激活信号平均强度,分析BOLD-fMRI数据与PVEPP100波潜时的相关性。结果正常组与视神经炎组枕叶视皮层、颞下回、后顶叶都有不同程度的兴奋,主要兴奋区位于枕叶距状裂周围。与对侧眼相比,视神经炎患眼刺激的皮层激活像素减少、激活信号平均强度降低。治疗4周后,患眼视力提高,皮层激活像素明显增多,屏状核、额前叶、丘脑亦有不同程度的兴奋。P100波潜时与皮层激活像素数呈负相关。结论功能磁共振成像技术可以反映视神经炎的皮层功能改变,为视神经炎的临床诊断和预后评估提供新的依据。     

非动脉炎性前部缺血性视神经病变患者眼底影像检查特征及其与视力、病程转归的关系

目的 观察非动脉炎性前部缺血性视神经病变(NAION)患者的荧光素眼底血管造影(FFA)与光相干断层扫描(OCT)检查等影像特征.探讨其与视力、病程转归的关系.方法 回顾分析47例临床确诊的NAION患者47只眼的FFA、OCT检查资料.所有患者均接受视力、眼底、视野等常规眼科检查.初诊时同时进行FFA和OCT检查.FFA及视野检查按常规方法进行;OCT检查分别选择线性和环形扫描方式,进行黄斑和视盘的扫描.其中35例NAION患者分别于发病后0.5、1、2、3、6个月时进行OCT复查.回顾分析时,以36例患者的对侧健眼作为对照组,对比分析患眼FFA、视野、视盘OCT图像特征与视力、病程转归的相互关系.结果 FFA检查结果显示,所有患眼均表现为早期视盘充盈迟缓,晚期视盘呈强荧光渗漏,24只患眼在黄斑区出现强荧光渗漏.OCT检查结果显示,所有患眼视盘隆起,生理凹陷变窄或消失;视盘与黄斑(盘斑)之间神经上皮层组织增厚或神经上皮层隆起,下方有液性暗区.对照眼中,14只跟有正常视盘生理凹陷,22只眼无生理凹陷或较小的生理凹陷.NAION组0.5个月时黄斑中心凹处神经上皮层厚度、盘斑间神经上皮层最大厚度,视盘周围视网膜神经纤维层厚度均高于对照组,差异均有统计学意义(F＝6.51,26.12,75.49;P<0.05).2个月时盘斑间神经上皮层最大厚度、视网膜神经纤维层平均厚度、视盘颞侧视网膜神经纤维层厚度较0.5个月时变薄.3个月时视网膜神经纤维层平均厚度、视盘颞侧视网膜神经纤维层厚度较0.5个月时明显变薄,低于对照组,差异有统计学意义(F＝75.49,37.92;P<0.05).视野检查结果显示,下方视野缺损21例,占45.7%.OCT检查结果显示,随病程进展,视盘上方神经纤维层厚度下降的程度更明显,与视野的表现相一致.视力与黄斑中心凹处神经上皮层厚度、盘斑间神经上皮层最大厚度、视网膜神经纤维层平均厚度、视盘颞侧视网膜神经纤维层厚度呈显著负相关关系(r=-0.394,-0.424,-0.412,-0.464;P<0.05).结论 NAION患者FFA特征为早期视盘充盈迟缓,晚期视盘呈强荧光渗漏;OCT特征为随病程发展,视网膜神经上皮层增厚,神经纤维层变薄.视盘形态及视网膜神经纤维层变化的OCT检查与视野检查结果一致;患者视力与神经上皮层厚度的OCT检查结果呈负相关关系.     

18例急性区域性隐匿性外层视网膜病变的临床分析

[目的]观察急性区域性隐匿性外层视网膜病变(AZOOR)的临床特征.[方法]临床确诊为AZOOR的18例患者18只眼纳入研究.所有患者均行矫正视力、眼底、视野、视网膜电图(ERG)检查.部分患者同时行荧光素眼底血管造影(FFA)、光相干断层扫描(OCT)、视觉诱发电位(VEP)及多焦视网膜电图(mf-ERG)检查.观察患者的临床特征.对比分析患眼与对侧眼的视觉电生理检查结果.分析同时行OCT、视野和mf-ERG检查者的检测结果一致性.[结果]患者中,男性3例,女性15例;均为单眼发病.其中,正视2只眼,占l1.1％;近视16只眼,占88.9％.无明显眼底改变11只眼,占61.1％;黄斑区附近单发黄白色点状病灶或视网膜色素上皮改变3只眼,占16.7％;颞侧呈区域性脱色素改变4只眼,占22.2％.所有息眼中心视野异常,周边视野正常.行OCT检查的患眼均存在不同程度光感受器细胞内外节连接(IS/OS)光带中断、缺失或毛糙.ERG检查发现,与对侧眼比较,患眼视杆反应b波,最大反应a/b波,视锥反应a、b波及30 Hz闪烁光反应振幅均降低,差异有统计学意义(t=3.516,2.689,3.103,3.517,2.999,3.309;P＜0.05);除视杆反应b波潜伏期差异无统计学意义外(t=1.023,P=0.306),其余波潜伏期均较对侧眼延长,差异有统计学意义(P＜0.05).VEP检查发现,患眼P100波振幅较对侧眼降低,差异有统计学意义(t=2.040,P=0.041);患眼与对侧眼P100波潜伏期比较,差异无统计学意义(t=1.687,P=0.092).行mf-ERG检查的患眼均存在振幅改变.OCT与mf-ERG检测结果具有良好的一致性;而中心视野与mf-ERG检测结果不完全一致,其异常区域分布不相吻合.[结论]AZOOR以青年女性、近视眼发病为多见;通常无明显眼底改变;但中心视野及视觉电生理检查存在异常,OCT检查可见其存在不同程度的IS/OS光带中断、缺失或毛糙.     

学术快讯

功能性磁共振成像(fMRI)测量青光眼患者视皮层功能与视野丢失的关系灵长类实验性青光眼研究显示,外侧膝状体神经元变性且视皮层活动性改变。青光眼患者死后的尸检也发现在视神经、外侧膝状体和视皮层中神经元发生变性。fMRI是一种非侵入性、特异性推断神经功能活动的检查方法,应用该技术可在活体评价青光眼视路神经元的活动性变化。研究表明视皮质组织功能变化与原发性开角型青光眼(POAG)视野丢失有一致性关联。fMRI是一种有潜力的、定量测定青光眼神经活动性变化的检查手段。     

双侧枕叶梗塞的视野改变特点临床观察

目的　探讨双侧枕叶梗塞的视野改变特征。方法　对 11例 (2 2只眼 )双侧枕叶梗塞患者进行视野检查 ,采用 APS- 6 0 0 0型全自动电脑视野仪 ,检测波长 5 80 nm,刺激持续时间 30 0 m s,间隔时间 30 0 m s,检测范围 6 0°,观察灰度图、伪彩色阈值图和 0°剖切等视线变化。结果　 11例 (2 2只眼 )中 ,同侧偏盲 9例 ,超过中线相合性视野缺损 2例 ,16只眼黄斑回避 ,6只眼黄斑对劈。等视线改变与视野改变对应良好 ,伪彩色阈值图改变比灰度图灵敏。结论　双侧枕叶梗塞在不同发展阶段具有不同的视野变化特征 ,有助于临床早期诊断     

放射性视神经病变临床分析

目的 探讨放射性视神经病变(RON)的临床特点、影响因素、诊治方法及其转归.方法 回顾性系列病例研究.对1999年6月至2010年10月中山大学中山眼科中心收治的35例(60只眼)RON住院患者的临床资料进行回顾性分析.结果 共收集35例(61只眼)RON患者的临床资料.所有患者均以进行性、无痛性单眼或双眼视力下降为主要表现.18例(51.4％)在完成放射治疗后3年内出现眼部症状.43只眼(70.5％)的患眼入院时中心最佳矫正视力＜0.05或视野0°.可窥见眼底的52只眼中,41只眼(78.8％)视乳头边界清晰,11只眼(21.2％)视乳头水肿和(或)出血、渗出.视乳头边界清晰的41只眼中,视乳头正常6只眼(14.6％),视乳头色较淡30只眼(73.2％),视乳头苍白5只眼(12.2％).14只眼有视野检查记录,主要表现为神经纤维束损害性视野缺损,其中7只眼(50％)表现为上方和(或)下方弓形暗点,3只眼(21.4％)出现中心和(或)旁中心暗点,2只眼伴生理肓点扩大,1只眼伴旁中心暗点,1只眼见鼻上象限缺损.23只眼有视网膜荧光血管造影检查结果,主要的改变为视乳头低荧光和视网膜毛细血管无灌注区.图形视觉诱发电位检查发现,83.3％出现振幅降低和(或)潜伏期延长.分别用糖皮质激素治疗、高压氧、高压氧联合糖皮质激素、视网膜激光光凝等治疗,只有10只眼(16.4％)视力有不同程度的改善.结论 RON潜伏期变异大,造成的视力和视野损伤重,视功能预后极差,主要眼部损伤为视网膜血管闭塞和不同程度视神经萎缩.目前针对并发症的保守治疗能短期改善视力.     

垂体瘤169例患者视野分析

目的 比较垂体瘤患者术前中心静态视野与周边动态视野,探讨术前视野缺损的危险因素和术后视野改善的影响因素.方法 回顾性系列病例研究.2006年2月至2007年2月确诊为垂体瘤的患者169例(338只眼),于术前行视力、眼底、视野及影像学检查.其中,334只眼行周边动态视野检查;323只眼行中心静态视野检查.28例(56只眼),于术后3～6个月进行视力、中心静态视野及周边视野随访.连续变量符合参数检验的采用t检验,非参数检验采用秩和检验;分类变量采用卡方检验或Fisher精确检验.对影响因素行Logistic回归分析.结果 169例患者中,36例双眼视野正常,133例单眼或双眼视野缺损;323只眼行中心静态视野检查,视野正常眼占28.48%(92/323),视野缺损眼占71.52%(231/323);334只眼行周边视野检查,视野正常眼占41.32%(138/334),视野缺损眼占58.68%(196/334);视野正常组与缺损组,起病年龄和垂体瘤直径及术前最佳矫正视力间差异有统计学意义(t=4.802、7.930;x~2=28.210,P＜0.01),经多因素分析,其均为术前视野缺损的影响因素.垂体瘤摘除术后,患眼最佳矫正视力恢复正常或改善占69.05%(29/42),视野恢复正常或改善占85.71%(36/42);视野恢复正常组与改善组,起病年龄和术前颞上方视野缺损情况两组间差异有统计学意义(t=2.525,P=0.023;x~2=6.218,P=0.013).结论 中心静态视野检查较周边视野检查敏感,可发现垂体瘤患者的早期视野改变.起病年龄、肿瘤直径以及最佳矫正视力是术前视野缺损的危险因素.起病年龄与术前颞上方视野缺损程度在术后视野恢复正常组与改善组存在统计学差异.     

AccuMaP多焦视觉诱发电位客观视野检查在黄斑疾病视功能检测中的应用

目的 探讨AccuMap多焦视觉诱发电位(mfVEP)客观视野检查在黄斑疾病视功能检测中的应用价值.方法 临床确诊为黄斑疾病的37例患者46只眼纳入研究.采用AccuMap mfVEP客观视野计检测患者半径为2.0°、5.5°、10.0°、15.5°和24.0°中心视野的平均反应振幅值.应用概率灰度图和系统自动计算出的AccuMap视野损伤严重程度指数(ASI)表示视野区域缺失情况.同时,采用MP-1微视野计检测患者半径为2.0°、4.0°、6.0°、8.0°和10.0°中心视野的平均光敏感度(MS)和半径为10.0°中心视野的平均缺失敏感度(MD).对比分析患者最小视角对数(logMAR)最佳矫正视力(BCVA)、平均反应振幅、MS、ASI及MD之间的相关性.结果 AccuMap mfVEP客观视野计检测显示,46只患眼中43只眼ASI异常,且概率灰度图上有明确的视野缺失,占93.45%;3只眼ASI正常,且概率灰度图上无视野缺失,占6.55%.半径为2.0°、5.5°、10.0°、15.5°和24.0°中心视野的平均反应振幅值分别为(120.78±52.91)、(134.31±54.67)、(149.99±52.42)、(156.69±48.30)和(157.54±45.07)nV;ASI值平均为74.26±52.43.MP-1微视野计检测显示,半径为2.0°、4.0°、6.0°、8.0°和10.0°中心视野的MS值分别为(10.97±5.91)、(12.71±5.13)、(13.71±4.53)、(14.23±4.18)、(14.48±3.86)dB;半径为10.0°中心视野的MD值为(4.49±3.07)dB.ASI、各半径中心视野的平均反应振幅与患眼logMAR BCVA间均存在明显相关性(P＜0.05).半径为2.0°、5.5°、10.0°中心视野的平均反应振幅与半径为2.0°、6.0°和10.0°中心视野的MS呈明显正相关(r=0.477,0.432,0.433;P=0.001,0.003,0.003).ASI与半径为10.0°中心视野的MD呈明显正相关(r=0.729,P=0.000).结论 AccuMap mfVEP客观视野检查能客观反映黄斑功能改变,可应用于黄斑疾病的视功能检测.

Abstract：

Objective To evaluate the value of AccuMap multifocal visual evoked potential (mfVEP) objective perimetry in measuring visual function of macular diseases. Methods Forty-six eyes (37 patients)with macular diseases were studied. The mean mfVEP amplitudes of central visual field within radius 2.0°,5.5°, 10.0°, 15.5° and 24.0°were measured by AccuMap mfVEP objective perimetry. Automatically calculated AccuMap severity index (ASI) represented the visual field defects. Meanwhile, the mean sensitivity (MS) of central visual field within radius 2. 0°, 4.0°, 6.0°, 8. 0° and 10. 0° and mean defect (MD) of central visual field within radius 10.0° were assessed by MP-1 microperimeter. The correlations among those parameters including logMAR visual acuity, mean mfVEP amplitudes, MS, ASI and MD were analyzed. Results Among 46 affected eyes, AccuMap mfVEP objective perimetry showed abnormal ASI with visual field defects in 43 eyes (93.45%), normal ASI without visual field defects in three eyes (6. 55 %). The mean mfVEP amplitudes value of the central visual field within radius of 2.0°, 5.5°, 10. 0°,15.5°and 24.0° were (120.78±52.91), (134.31±54.67), (149.99±52.42), (156.69±48.30),(157.54±45.07) nV respectively. The mean ASI value was 74. 26±52.43. MP-1 showed that the MS values of central visual field within radius 2.0°, 4.0°, 6.0°, 8. 0° and 10. 0° were (10. 97±5.91), (12. 71±5. 13), (13. 71±4. 53), (14.23±4. 18), (14.48±3. 86) dB respectively. The MD value of central visual field within radius 10° was 4.49± 3.07. There was a significant correlation among ASI, the mean mfVEPamplitudes of central visual field with every radius and logMAR best corrected visual acuity (P＜0. 05). The mean mfVEP amplitudes of central visual field within radius 2. 0°, 5. 5°, 10.0° were positively correlated with the MS of central visual field within radius 2. 0°, 6. 0°, 10.0° (r=0. 477, 0. 432, 0. 433; P=0. 001,0. 003, 0. 003). Furthermore, ASI was also correlated with MD of central visual field within radius 10.0°(r=0. 729, P = 0. 000). Conclusions AccuMap mfVEP objective perimetry can reflect the changes of macular function objectively and can be used to assess the visual function of macular diseases.     

Patterns of visual loss associated with pituitary macroadenomas

Purpose: To describe the patterns of visual loss associated with pituitary macroadenomas compressing the anterior visual pathway.
Method: A prospective survey of 29 patients with pituitary macroadenomas who presented to the neurosurgical unit at St Vincent's Hospital, Melbourne. Selected patients had histologically verified pituitary macroadenomas, and visual defects (acuity, colour and/or field loss) consistent with anterior visual pathway compression.
Results: All patients had visual field defects detected on perimetry, and the majority were asymmetrical. Bitemporal defects were most common but field defects ranged from monocular defects to generalised constriction. Four patients (13.8%) did not report visual symptoms, and of those who had symptoms, blurred vision was the most common complaint. Ninety-six per cent of eyes had field loss, 56% had decreased colour vision, 46% had decreased acuity, 31% had optic disc pallor, and 2% had an ophthalmoplegia.
Conclusions: Patients with visual pathway compression by pituitary macroadenomas may be asymptomatic despite having field defects. Perimetry is the most sensitive method of identifying compression, followed by colour vision, visual acuity, then the presence of optic atrophy. Automated static threshold perimetry appears to show early field defects better than manual kinetic perimetry. All patients with pituitary macroadenomas should have thorough ophthalmological examinations, including perimetry to document visual deficits secondary to compression.     

多焦视诱发电位在青光眼视野损害检测中的应用

目的了解多焦视诱发电位(mfVEP)在青光眼视野损害检测中的作用。设计病例对照研究。研究对象 20例正常人和20例原发性青光眼患者。方法对20例正常人和20例原发性青光眼患者应用RETIscan mfVEP记录系统3．20行检查, 分别测量所有受试者mfVEP每一位点记录曲线的振幅,并计算受试者的双眼视网膜反应不对称系数(RAC)。比较青光眼患者 mfVEP检查的暗点与OCTOPUS 101型自动视野计G2程序检查的视野缺损区的对应性。主要指标振幅、RAC。结果在与自动视野计检查发现的视野缺损相对应的部位,90％患眼的mfVEP表现为至少3个相邻位点的振幅降低或RAC超出正常人数据库均数的2倍标准差(SD)。其中63％患眼表现为至少3个相邻位点的振幅降低超出正常人均数的2 SD,70％患眼表现为至少3个相邻位点的RAC超出正常人均数的2 SD。有2例患者(2眼)的自动视野计检查结果正常,但mfVEP显示有视野异常。正常人中无一眼的mfVEP表现为视野异常。结论 mfVEP有可能作为青光眼视野损害的客观检查手段。     

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.     

蓝/黄视野检查法对原发性开角型 青光眼的早期诊断价值

目的探讨蓝/黄视野检查法(blue-on-yellow perimetry,B/Y PM)对青光眼的早期诊断价值。 方法利用OCTOPUS 101全自动视野计G2程序分别对16例(32只眼)正常人,25例(35只眼)白/白视野检查(white-on-white perimetry,W/W PM)异常的原发性开角型青光眼(primary open-angle glaucoma,POAG),15例(15只眼)W/W视野检查正常的早期POAG及11例 (22只眼)可疑POAG进行B/Y视野检查。结果正常人、 可疑POAG、早期、中期及晚期POAG B/Y视野检查视网膜平均敏感度分别为(23．24±1．22 )dB、(20．97±3．42)dB、(18．44±3．570dB、(11．04±1．85)dB及(8 ．55±2．29)dB。B/Y 视野检查法对检测青光眼视野损害的敏感性高于常规W/W视野检查法,敏感性为92％,特异性为 90．62％。早期和中期POAG中,B/Y视野检测出视野缺损点数明显多于W/W视野检测出的缺损点数。结论B/Y视野检查 法是检测POAG早期视野损害的敏感方法之一。(中华眼底病杂志,2001,17:125-127)     

Pattern ERG and psychophysical functions in Best's disease

The aim of the study was to asses the neurosensory retinal function in 12 patients (24 eyes) with different stages of Best's disease, by determining how pattern and full field flash ERG responses were related to visual acuity, stage of disease and extent of visual field loss. All patients had typically abnormal EOG responses and normal full field-flash ERG responses. Patients were stratified in two groups according to visual acuity. In the first group 12 eyes with visual acuity better than 0.5, all amplitudes and latencies of PERG P50 and N95 responses were in the normal range. Small central scotoma was detected by static perimetry in four of these eyes. In the second group of 12 eyes with visual acuity 0.5 or less, PERG showed reduced both P50 and N95 amplitudes in five eyes, and N95 solely, in two eyes. All patients had central scotomas detected by static perimetry. Progression of the disease, seen in deterioration of visual acuity and progression of central visual field defects, corresponded well with reduction of both PERG P50 and N95 amplitudes. There was no correlation found between visual acuity and EOG responses. Our results show that in Best's distrophy, pattern ERG is getting abnormal with progression of the disease, indicating relative preservation of neurosensory retina in initial stages of the disease. In contrast to EOG - being abnormal in all the patients regardless of the stage of disease - and full field-flash ERG - being normal in most of the patients - PERG gives opportunity for electrophysiological determination of the progression of the disease.     

准分子激光原位角膜磨镶术前后蓝／黄视野分析

目的研究准分子激光原位角膜磨镶术（laser in situ keratomileusis,LASIK）对患者视野的影响。方法用Octopus101全自动视野计G2程序的TOP／BY分程序对LASIK手术的近视患者于术前、术后6个月行视野检查。结果术后视野的平均敏感度（meansen sitivity。MS）与术前比较，差异无显著性（P〉0．05）。术后视野的指数平均缺损（mean defect，MD）与术前比较。差异有显著性（P〈0．01）。手术前、手术后视力与手术前后各自视野MS、MD均无显著相关性（P〉0．05）。手术前后MS和MD平均差值与术前屈光度数、角膜切削百分比、激光切削时间、负压吸引时间、瞳孔直径、年龄、性别等行Spearman相关分析显示均无相关性（P〉0．05）。结论手术对视网膜和视神经结构和功能影响还不足以导致临床上明显的功能损伤，没有表现出有临床意义的功能改变。LASIK手术前后视野无明显变化。蓝，黄视野计与标准白色视野计检测的视野结果一致，说明两者检测敏感性相当。     

High-pass resolution perimetry in optic neuritis

The topography of visual field defects resulting from optic neuritis as measured by spatial resolution perimetry is not known. Using high-pass resolution perimetry, the number and severity of visual field defects in the central visual field was determined in 18 patients with resolved optic neuritis and 18 age-matched controls. Comparisons were made between three groups of eyes: (1) the involved eyes of the patients, (2) the uninvolved eyes of the patients, and (3) the eyes of the controls. Concentric zone analysis showed the involved eyes to have depression of the visual field in all zones with slightly more loss centrally. The "uninvolved" eyes showed a mild equal depression in all zones. Spatial resolution acuity measurements (which correlate directly with the spatial separation of retinal ganglion cell receptive field centers) indicated that the percentage of functioning retinocortical channels for normal eyes, uninvolved eyes, and involved eyes were 112%, 94%, and 58% of the reference normal values, respectively. These differences were all statistically significant. Resolution perimetry of the central visual field of eyes with resolved optic neuritis involves the cecocentral and Bjerrum areas. The loss was often patchy and a combination of cecocentral and arcuate defects. There was also a mild generalized depression of the uninvolved eye.     

Glucose utilization of visual cortex following extra-occipital interruptions of the visual pathways by tumor. A positron emission tomography study

To assess the effect of extra-occipital lesions on the local cerebral glucose utilization of the primary and associative visual cortex, 29 patients were studied in the unstimulated state by positron emission tomography and [18F]2-deoxyglucose. Quantitative Goldmann perimetry was done in each patient at the time of the positron emission tomographic study. Nine patients showed homonymous defects, either hemianopsia or quadrantanopsia, whereas nine patients had heteronymous defects. Eleven control subjects, free of any neurological symptoms and with normal visual fields, were also studied with [18F]2-deoxyglucose positron emission tomography. In the normal control subjects and in patients with a heteronymous defect, left-to-right differences in the local cerebral metabolic rate for glucose of the visual cortex varied less than 10%. In patients with hemianopic defects, differences ranged from 8 to 38%, with the hypometabolic cortex always contralateral to the field defect. In patients with quadrantanopic defects, the visual cortex contralateral to the field defect demonstrated differences from 14 to 24% above and below the calcarine fissure, the cortex that received greater input from the affected field being hypometabolic.