人眼正常周边视野的规律性变化

背景：周边视野检查即是眼科检查中重要的组成部分之一，人眼正常周边视野的规律性变化及其影响因素目前仅限于定性分析，无较为准确的定量分析。目的：探讨光标大小、亮度和颜色变化对人眼各个子午线方向上周边视野的影响。设计：非随机对照研究。地点和对象：实验在天津职业大学视光学实验中心完成，对象选择天津职业大学年龄19～21岁大学生正视眼自愿者15例，男6例，女9例。排除高度屈光不正者。干预：使用弧形板视野计，分别用不同大小、不同亮度、不同颜色的光标对15例受试者进行周边视野的测试与分析。主要观察指标：人眼在各个子午线方向上的正常平均周边视野。结果：在光标亮度、颜色一定的情况下，光标直径由大变小，在各个子午线方向上的正常平均周边视野均递减；在光标大小、颜色一定的情况下，光标亮度由大变小，在各个子午线方向上的正常平均周边视野均递减；在光标亮度、大小一定的情况下，颜色光标白、蓝、红、绿的周边视野依次递减。结论：人眼的周边视野，随着测试光标的大小、亮度、颜色的变化而有规律地发生变化。     

人眼周边视野缺陷的定量分析方法研究

目的:对周边视野检查常常是根据临床经验判断病眼周边视野病变的大小及位置,存在主观影响。人眼周边视野缺陷定量分析方法可以减少人为因素的影响。方法:①周边视野检查采用的是弧形板视野计,对传统的仪器进行了改造,将记录针改为记录笔,在记录纸上记录一系列离散的点图,用CCD数字照相系统将纸记录转化为数字图像。②利用禁忌搜索算法对离散点进行搜索,找到病眼周边视野曲线,并将病眼视野曲线同标准视野曲线进行比较,得到视野缺陷图。利用图像处理中的区域标识与面积计算方法可得到视野缺损面积的定量结果。结果:①通过计算机可绘制周边视野图,将病眼曲线与标准曲线在同一视图中显示,或者将病眼的历次检查结果曲线在同一视图显示,便于医生对病情进展或治疗情况进行分析。②可以得到视野缺陷图,并可对视野缺陷面积进行定量分析。结论:此方法可以进行周边视野缺陷定量分析,为周边视野缺陷的准确分析提供可靠依据。     

四点视野计的研制

为满足大规模青光眼快速筛查的需要,文章利用新的视野检查策略,研制了四点视野计.该由上位机、下位机及其通信接口构成,上位机即PC机向下位机发送命令,并对单片机传递的信号进行处理及分析;下位机即单片机土要控制发光二极管的亮度变化及检测顺序,并把受检者应答情况传递给上位机.单片机与PC机之间通过串行通信方式实现数据传输.单片机软件采用C语言设计,PC端软件采用VB6.0编制.实现了亮度控制、界面显示、患者资料管理、数据传输及处理等功能,完成了可用于临床检查的四点视野计样机.该仪器结构简单、检测时间短、功能齐全、便于携带,方便进行临床实验,为将来深入人群进行青光眼快速筛查提供了条件.     

磁共振小视野弥散加权成像技术在影像诊断中的研究进展

磁共振弥散加权成像作为一种功能成像已经成为常规磁共振成像诊断中的重要组成部分。然而在目前的临床应用中较为广泛使用的全视野弥散加权成像技术,其图像质量较差,解剖结构分辨率较低,容易产生比较严重的伪影,图像的变形和失真等问题。随着技术的进展,小视野弥散加权成像技术通过在相位编码方向上缩减视野大小等方法显著提高了图像质量及组织结构分辨能力,减轻图像伪影、变形、失真等情况,这对于体积较小、结构精细、解剖部位附近磁化率变化较大或易受不自主生理性运动影响的器官及部位尤为重要。作者对小视野弥散加权成像的成像原理及其在各器官中的研究进展进行综述。     

非动脉炎性前段缺血性视神经病变和特发性视神经炎患者视野变化的对比研究

目的探讨不同视神经病患者视野缺损变化并分析其与视力的关系。方法以特发性视神经炎(ION)和非动脉炎性前段缺血性视神经病变(NAION)患者作为研究对象,收集2011年2月至2014年2月该院就诊的100例患者,其中ION患者50例72眼,NAION患者50例61眼,比较2组患者的性别、年龄、视力值、瞳孔大小、视野检测完成时间和缺损特点、视野模式缺损(PSD)和平均缺损(MD)情况。结果 2组患者平均年龄分别为(41.92±8.64)、(53.98±12.71)岁,2组患者男女性分别为6、44例和17、33例,视力(BCVA)、视野完成检测时间、MD和PSD比较,差异均有统计学意义(P0.05)。结论 ION和NAION的视野变化受多种因素影响且具有各自的病理特征,可为视神经疾病的鉴别诊断提供依据。     

以ZEMAX光学设计软件实现光线追迹:分析人工晶体前移与人眼屈光调节的关系

背景:人工晶体在白内障术眼囊袋内可以前移,但目前还不能够对该动态调节过程中人眼屈光变化进行监测,临床数据的难以获得使人工晶体前移与引起的人眼屈光调节量之间的关系目前还未明确.目的:观察人工晶体眼内移动对人眼屈光调节力的影响.方法:基于Hwey-Lan Liou眼模型,采用ZEMAX光学设计软件实现光线追迹的方法研究了人工晶体在眼内的前移与人眼屈光调节量的关系.结果与结论:人工晶体每前移一定的距离,人眼所获得的屈光调节量不恒定;调节量大小依赖于眼轴长度和所需植入的人工晶体,特别是眼轴长度;对于不同眼轴长度术眼中的人工晶体前移,人眼所获得的屈光调节量与眼轴长度呈负相关.     

垂体大腺瘤患者视觉皮层的fMRI观察

目的 采用fMRI方法评价垂体大腺瘤患者视觉中枢的激活形式,观察视野改变与初级视觉皮层功能变化之间的关系.方法 对23例伴视交叉受压的垂体大腺瘤患者及18名正常志愿者的左右眼分别进行组块设计的fMRI实验,刺激内容为全视野黑白翻转棋盘格,对照内容为黑色屏幕中心的白色"+",6个对照组块与5个刺激组块交替进行,每个组块20 s.采用1.5T MR扫描仪.数据后处理采用SPM2软件.采用两样本t检验的组间分析方法分别获得左眼及右眼刺激下患者组与对照组间的激活差异图.分析患者视野缺损类型与初级视觉皮层激活形式之间的对应关系.结果 在严格控制头动和机械噪声等影响因素后,最终左、右眼刺激各入组12例.患者组与对照组比较,初级视觉皮层激活范围及强度均明显缩小,左眼刺激时患者组以右侧初级视觉皮层激活下降为主,右眼刺激时患者组以左侧初级视觉皮层激活下降为主.6例患者表现为典型左颞侧视野缺损,左眼刺激时表现为左侧初级视觉皮层激活,而右侧激活明显下降或无激活.7例患者为典型右颞侧视野缺损,右眼刺激时表现为右侧初级视觉皮层激活,而左侧激活明显下降或无激活.结论 垂体大腺瘤患者初级视觉皮层的激活形式与视野缺损类型存在对应关系,颞侧视野缺损主要以对侧初级视觉皮层激活下降为主.fMRI是研究前视路病变对视觉中枢皮层影响的有效方法.     

垂体腺瘤急性卒中行经蝶手术前后视力视野的变化

目的:探讨垂体腺瘤急性卒中患者经蝶手术前后的视力视野改善情况.方法:回顾性分析46例合并视力视野受损的垂体腺瘤急性卒中患者的病例资料.13例在入院3 d内急诊手术,17例在3～7 d内手术,16例7 d后手术.结果:经蝶手术治疗后视力缓解率93.48%(43/46).视野为89.13%(41/46)(P＜0.05).入院3 d内行手术者13例,视力视野完全恢复者9例,部分恢复3例,元明显好转l例.3～7d内手术者17例,视力视野完全恢复者8例,部分恢复9例.7 d后手术者16例,视力视野完全恢复者4例,部分恢复者10例,无明显好转1例,恶化1例.结论:垂体腺瘤急性卒中应尽早经蝶手术,手术能大大改善患者预后,尤其对改善患者视力视野效果明显,1周内手术效果明显.     

单眼散光弱视儿童对比敏感度的研究

目的：分析探讨单眼散光弱视患儿对比敏感度（CS）视功能的受损特点。方法：对正常儿童组36例、单眼散光弱视组34例、单眼非散光弱视组33例,共103例,用静态F.A.C.T图表和计算机Gabor斑CS检查程序分别检查患儿对侧眼、弱视眼及90°和180°两主子午线方向上的对比敏感度。结果：①单眼散光弱视组和单眼非散光弱视组的对侧眼、弱视眼的CS值在所有空间频率均较正常组的CS降低（P〈0.05）,表现为中、高空间频率区CS的明显受损（P〈0.01）。②单眼散光弱视组的弱视眼在90°和180°两主子午线方向上的对比敏感度有显著差异（P〈0.01）。结论：弱视儿童的对侧眼不正常。用计算机Gabor斑检查可以了解弱视散光儿童不同子午线上的CS存在的差异,明确定位弱子午线,并可以针对子午线性弱视,进一步开展知觉学习的治疗。     

Octopus 101视野计检测结果的可信度分析

目的 通过对Octopus101视野计检测的可信度分析,探讨影响检测结果可靠性的因素。方法 采用Octopus101视野计对门诊129例被检者(244眼)进行视野检查,分析被检者视野缺损程度与假反应率的关系。结果Octopus101视野计检测视野结果的假反应率(RF值)≤15％有172眼(70％);>15％有72眼(30％),其中仅有假阳性反应23眼,包括正常视野19眼(83％),仅有假阴性反应29眼,包括严重视野缺损22眼(76％)。不同视野缺损程度的被检者其假阳性、假阴性反应率有显著差异(P<0.01)。结论 RF值可以在一定程度上反应Octopus101视野计视野结果的可信度。RF值>15％者假阳性反应率高与被检者年龄小有关;而假阴性反应率高与被检者视野严重缺损和年龄大有关。因此,检查中应尽可能避免影响因素,并根据实际情况正确评价RF值的临床意义。     

Response properties of prefrontal visual neurons in the awake monkeys

Response properties of the visual neurons in the prearcuate and periprincipal areas of the prefrontal cortex were examined in awake monkeys. The findings obtained are as follows: (1) Most of the visual neurons responded with various excitatory fashions to a light spot presented in their visual receptive fields (RFs). The response was large when the stimulus was applied to the middle of the RF and became smaller when the stimulus position was moved from this part toward the RF border. (2) The response was affected by the size of the stimulus. The largest response was usually obtained by a small stimulus. The shape, orientation, brightness of the stimulus and the direction of its movement gave little influence on the response strength and pattern. (3) In about a half of the neurons the response was enhanced when the monkey made a saccadic eye-movement toward a visual stimulus in the RF. (4) Some of the above-mentioned response properties were quantitatively different from one another among neuron groups classified according to the eccentricity and size of their RFs. These results suggest that the properties of the neurons are suitable for detecting a visual stimulus occupying a limited extent in the space.     

射频消融猪甲状腺毁损灶形成的实验研究及意义初探

目的:探讨射频消融技术对猪甲状腺组织的影响,以了解毁损灶的形成大小与时间、功率的关系以及射频消融猪甲状腺组织的病理变化。方法:利用射频仪和外裸长5mm、直径2mm电极,分别予不同功率和时间对离体猪甲状腺组织进行消融,测量毁损灶的大小以及进行病理学检查。结果:单电极毁损灶为类圆形,在射频功率为60W时,随时间的延长,毁损坏死灶明显增加;当功率为70W时随时间的延长,毁损坏死灶范围虽增加但量有限;当功率为80W时,毁损坏死灶大小与时间没有明显相关性,大小趋于稳定。毁损区域甲状腺组织变硬,呈灰白色,与周围组织分界清楚;光学显微镜下消融区组织细胞形态和正常甲状腺组织无明显差别。结论:单根电极对甲状腺组织射频消融可形成最大直径为10.1mm的类圆形消融灶。当功率小于70W时,其射频毁损的范围大小是可以调节的,其大小与功率、时间呈正相关。     

Color temperature’s impact on task performance and brainwaves of school-age children

[Purpose] This study investigated color temperature’s impact on task performance. It presents a scientific analysis of brainwave and task performance time changes, and the results of a self-report type survey. [Subjects] Twenty-four elementary school fifth-grade boys and girls with no visual problems participated in the experiment. [Methods] Physiological reaction times of task performance were measured in a laboratory that could fix and maintain color temperature. Brainwave changes and the task performance times were measured, and a self-report questionnaire was conducted in order to measure of emotional reactions. [Results] Regarding the brainwave changes associated with color temperature, alpha waves were emitted in the O2 area when puzzle tasks were illuminated by orange light and low and high beta waves were emitted in the F3 area under white light. Five items (Brilliant, Soft, Lively, Relaxed, Open) were reported predominantly in responses to orange light in the self-report questionnaire. [Conclusion] The results of this study show that relaxation and stability are not assured when the color temperature is low, and that concentration and cognitive activity are not necessarily easier when the color temperature is high. The color temperature change when performing tasks promoted emotional factors more than brainwave, a biological change.Key words: Physical environment, Brainwave, Color temperature     

Quantitative colorimetry of atherosclerotic plaque using the L*a*b* color space during angioscopy for the detection of lipid cores underneath thin fibrous caps

Objectives Yellow plaques seen during angioscopy are thought to represent lipid cores underneath thin fibrous caps (LCTCs) and may be indicative of vulnerable sites. However, plaque color assessment during angioscopy has been criticized because of its qualitative nature. The purpose of the present study was to test the ability of a quantitative colorimetric system to measure yellow color intensity of atherosclerotic plaques during angioscopy and to characterize the color of LCTCs. Methods Using angioscopy and a quantitative colorimetry system based on the L*a*b* color space [L* describes brightness (−100 to +100), b* describes blue to yellow (−100 to +100)], the optimal conditions for measuring plaque color were determined in three flat standard color samples and five artificial plaque models in cylinder porcine carotid arteries. In 88 human tissue samples, the colorimetric characteristics of LCTCs were then evaluated. Results In in-vitro samples and ex-vivo plaque models, brightness L* between 40 and 80 was determined to be optimal for acquiring b* values, and the variables unique to angioscopy in color perception did not impact b* values after adjusting for brightness L* by manipulating light or distance. In ex-vivo human tissue samples, b* value ≥23 (35.91 ± 8.13) with L* between 40 and 80 was associated with LCTCs (fibrous caps <100 μm). Conclusions Atherosclerotic plaque color can be consistently measured during angioscopy with quantitative colorimetry. High yellow color intensity, determined by this system, was associated with LCTCs. Quantitative colorimetry during angioscopy may be used for detection of LCTCs, which may be markers of vulnerability.     

左侧空间忽略患者关联性注意捕捉效应的研究

目的:探讨脑损伤后致左侧空间忽略患者的注意捕捉效应。方法:本研究对右侧大脑半球损伤伴左侧忽略的患者及健康被试各20例,分别进行神经心理学背景测试及关联性注意捕捉效应测试,观察左侧空间忽略患者与健康被试之间注意捕捉效应的差异,分析影响关联性注意捕捉效应强度的因素。结果:①与健康对照组相比,左侧空间忽略组的数字捕捉正确率明显降低(P<0.01)。②健康对照组:无论干扰刺激颜色与目标刺激颜色是否一致,左侧视野出现干扰刺激时的数字捕捉正确率均明显低于右侧视野出现干扰刺激时(P<0.01);无论干扰刺激在目标刺激的左侧或右侧,当干扰刺激颜色与目标刺激颜色一致时,数字捕捉正确率低于干扰刺激颜色与目标刺激颜色不一致时(P<0.01,0.05)。③左侧空间忽略组:无论干扰刺激颜色与目标刺激颜色是否一致,右侧视野出现干扰刺激时的数字捕捉正确率均低于左侧视野出现干扰刺激时(P<0.05);左侧视野出现的干扰刺激颜色与目标刺激颜色一致或不一致时,对数字捕捉正确率的影响差异无统计学意义,而右侧视野出现的干扰刺激颜色与目标刺激颜色一致时,数字捕捉正确率低于颜色不一致时(P<0.05)。结论:左侧空间忽略患者的注意功能下降,但无论对于健康受试者或者左侧空间忽略患者,符合目标刺激颜色特征的干扰刺激均能够增强非随意性地注意捕捉效应。     

Influence of colors on habituation of visual evoked potentials in patients with migraine with aura and in healthy volunteers

OBJECTIVE: To investigate whether colored glasses influence the habituation of visual evoked potentials. BACKGROUND: We have previously shown that during pattern-reversal stimulations lasting 2 minutes the amplitude of the visual evoked potential increases in migraine with and without aura between attacks, whereas it decreases in healthy volunteers. Red light was found to increase visually evoked EEG fast activity only in children with migraine with aura. Wearing rose-tinted glasses for 4 months decreased attack frequency in parallel with a reduction of the visually evoked EEG fast activity. METHODS: We compared the change in amplitude of the visual evoked potential using five different tinted glasses in 12 patients with migraine with aura and in 10 healthy volunteers. During continuous stimulation at 3.1 Hz, five blocks of 50 responses were sequentially averaged using red, yellow, green, blue, and grey glasses and without glasses in a random order and analyzed in terms of latencies and N1-P1 amplitudes. Amplitude changes were calculated for each block by comparison with the first block in every condition and analyzed statistically using Zerbe's method. RESULTS: In healthy volunteers, the visual evoked potential amplitude increased with red glasses compared to without glasses (P = .05) or with green glasses (P = .03). In patients with migraine with aura, no significant difference was detected using colored glasses. Our findings in healthy volunteers are in line with earlier reports of increased excitability of the human visual cortex when exposed to red light. The lack of such a pattern in patients with migraine with aura suggests that the visual cortex is interictally hypoexcitable rather than hyperexcitable, which is consistent with studies of transcranial magnetic stimulation.     

Central luminance flicker can activate peripheral retinotopic representation

We aimed to study cortical responses to uniform luminance stimulus in different conditions. We stimulated the central visual field with luminance flicker and reversal of checkerboard pattern contrast and mapped the visual field representation up to 50 degrees of eccentricity. Our results show spreading of cortical BOLD responses when visual stimulus contains mean luminance change in dark surround and no spreading when the stimulus surround has bright illumination. No cortical region was more sensitive to luminance flicker than to pattern reversal during both stimulation setups. We suggest that the spread of luminance responses in retinotopic cortical areas results from intraocular scattering of light. Light scattered inside the eye spreads visual stimulation on the retina, and the contrast of the scattered light is strongest when the surround of the stimulus is dark. The stray light is potential and often neglected source of an artefact in visual experiments, and the responses due to stray light can erroneously be interpreted as indicators for local cortical sensitivity to luminance.     

Subjective measurement of the Stiles-Crawford effect with different field sizes

The Stiles-Crawford effect of the first kind (SCE) is the phenomenon in which light entering the eye near the center of the pupil appears brighter than light entering near the edge. Previous investigations have found an increase in the directionality (steepness) of the effect as the testing location moves from the center of the visual field to parafoveal positions, but the effect of central field size has not been considered. The influence of field size on the SCE was investigated using a uniaxial Maxwellian system in which stimulus presentation was controlled by an active-matrix liquid crystal display. SCE directionality increased as field size increased from 0.5° to 4.7° diameter, although this was noted in four mild myopes and not in two emmetropes. The change with field size was supported by a geometric optics absorption model.     

Population receptive field estimates in human visual cortex

We introduce functional MRI methods for estimating the neuronal population receptive field (pRF). These methods build on conventional visual field mapping that measures responses to ring and wedge patterns shown at a series of visual field locations and estimates the single position in the visual field that produces the largest response. The new method computes a model of the population receptive field from responses to a wide range of stimuli and estimates the visual field map as well as other neuronal population properties, such as receptive field size and laterality. The visual field maps obtained with the pRF method are more accurate than those obtained using conventional visual field mapping, and we trace with high precision the visual field maps to the center of the foveal representation. We report quantitative estimates of pRF size in medial, lateral and ventral occipital regions of human visual cortex. Also, we quantify the amount of input from ipsi- and contralateral visual fields. The human pRF size estimates in V1-V3 agree well with electrophysiological receptive field measurements at a range of eccentricities in corresponding locations within monkey and human visual field maps. The pRF method is non-invasive and can be applied to a wide range of conditions when it is useful to link fMRI signals in the visual pathways to neuronal receptive fields.     

Treatment of severe glaucomatous visual field deficit by chiropractic spinal manipulative therapy: a prospective case study and discussion

OBJECTIVE: To discuss the case of a patient with severely reduced visual fields arising from terminal glaucomatous retinal damage and the treatment of this condition by spinal manipulation. CLINICAL FEATURES: A 25-year-old uniocular female patient with congenital glaucoma sought chiropractic treatment for spinal pain, headache, and classic migraine. Advanced optic disk cupping was present, and loss of vision was near complete. A 3-degree island of central vision and a small area of peripheral light sensitivity had remained relatively stable for 3 years after a trabeculectomy procedure that had resulted in intraocular hypotony. INTERVENTION AND OUTCOME: It was considered possible that chiropractic spinal manipulative therapy may have a positive outcome in visual performance. Before commencing chiropractic spinal manipulative therapy, an ophthalmologic examination was performed, and visual performance was monitored through a course of treatment. Immediately after the first treatment, significant visual field improvement was recorded in the remaining eye. Maximal improvement of vision was achieved after 1 week (4 treatment sessions). Total monocular visual field had increased from approximately 2% to approximately 20% of normal. Corrected central acuity had improved from 6/12 to 6/9. Independent reexamination by the patient's regular ophthalmic surgeon confirmed the results. CONCLUSION: Recovery of vision in this patient was an unexpected and remarkable outcome, raising the question of whether chiropractic spinal manipulative therapy may be of value in the management of glaucomatous visual field loss. More intensive research is required.