磁共振成像、视诱发电位和视野检查在视神经炎的临床应用

目的 探讨MRI、视诱发电位(VEP)和视野(Vision Field，VF)在视神经炎中的临床应用价值。方法 临床诊断为视神经炎者60例分别行MRI、VEP和视野检查，每例所有检查均在一周内完成，并将检查结果进行统计学处理和分析。结果 MRI阳性率最高(96．67％)，其次是视野和VEP(86．96％和75．58％)。同时发现MRI具有定位和一定的鉴别诊断作用。结论 VEP和VF结合MRI检查，三者相辅相成，将有助于视神经炎更早、更准确地诊断和治疗。     

A neural model of 3D shape-from-texture: multiple-scale filtering, boundary grouping, and surface filling-in

A neural model is presented of how cortical areas V1, V2, and V4 interact to convert a textured 2D image into a representation of curved 3D shape. Two basic problems are solved to achieve this: (1) Patterns of spatially discrete 2D texture elements are transformed into a spatially smooth surface representation of 3D shape. (2) Changes in the statistical properties of texture elements across space induce the perceived 3D shape of this surface representation. This is achieved in the model through multiple-scale filtering of a 2D image, followed by a cooperative-competitive grouping network that coherently binds texture elements into boundary webs at the appropriate depths using a scale-to-depth map and a subsequent depth competition stage. These boundary webs then gate filling-in of surface lightness signals in order to form a smooth 3D surface percept. The model quantitatively simulates challenging psychophysical data about perception of prolate ellipsoids [Todd, J., & Akerstrom, R. (1987). Perception of three-dimensional form from patterns of optical texture. Journal of Experimental Psychology: Human Perception and Performance, 13(2), 242-255]. In particular, the model represents a high degree of 3D curvature for a certain class of images, all of whose texture elements have the same degree of optical compression, in accordance with percepts of human observers. Simulations of 3D percepts of an elliptical cylinder, a slanted plane, and a photo of a golf ball are also presented.     

视觉诱发电位评价轻型视神经损伤

目的 探讨视觉诱发电位(VEP)在轻型视神经损伤患者视功能检查中的应用价值.方法 对25例面部或眼部外伤患者外伤后48h内行VEP检查,以对侧眼作为对照,观察P100潜伏期及振幅.结果 患眼VEP中P100潜伏期较对侧眼无明显延迟,P100振幅较对侧眼降低.结论 VEP检查对轻型视神经损伤的早期诊断及治疗有重要意义.     

特发性黄斑裂孔患者术后裂孔愈合形态与视功能恢复的研究

目的探讨特发性黄斑裂孔患者术后裂孔愈合形态与视功能恢复的关系。方法选择特发性黄斑裂孔1次性术后裂孔愈合患者36例(38只眼)的连续临床资料,进行回顾性分析。应用相干光断层扫描(OCT)观察裂孔愈合形态,采用激光扫描检眼镜(SLO)测定患者术前,术后1、3、6个月黄斑区光敏度、绝对暗点、相对暗点平均面积及中心视力,并对检测结果进行分析。结果根据OCT图像,裂孔形态分为完全愈合型(22只眼)、部分愈合型(10只眼)及未愈合型(6只眼)。术后6个月,完全愈合型和部分愈合型眼的中心视力、光敏度、绝对暗点和相对暗点的平均面积均较术前有明显改善(均P<0.05);未愈合型眼的中心视力、光敏度虽较术前改善,但绝对暗点、相对暗点差异则无显著意义(P>0.05);完全愈合型眼的视力、光敏度、绝对暗点改善程度与部分愈合型和未愈合型眼比较,差异有显著意义(P<0.05)。Ⅱ期裂孔眼术后黄斑中心凹形态可完全恢复。结论术后黄斑区中心凹部视网膜正常形态的恢复与视功能改善程度呈正相关(P<0.05)。术后中心凹的形态恢复越好,视功能改善程度越高。裂孔早期阶段(Ⅱ期裂孔)行手术,更有机会获取良好的视功能。(中华眼科杂志,2004,40:443-447)     

One-stage vs. two-stage adjustable sutures for the correction of esotropia

BACKGROUND The aim of this study was to evaluate the stability and the level of postoperative consciousness, nausea and vomiting, ocular pain, starting oral intake and activity, and cost-effectiveness in patients undergoing medial rectus recession surgery using an adjustable suture technique that was performed by two different methods. METHOD In this prospective study, we evaluated 78 patients undergoing medial rectus recession surgery. Thirty-eight patients were operated by a one-stage technique in which the whole operation was done under topical anesthesia and adjustment was done on the operating table, while 40 patients were operated by a two-stage technique in which the operation was done under general anesthesia and adjustment was done the following day at the patient’s bedside. The results were recorded and compared according to the parameters given above. A scoring system was used to assess all these parameters except for stability. The stability of the procedures was evaluated according to the degrees of squint immediately after the adjustment and at least three months thereafter. RESULTS There was no significant difference between the procedures with regard to stability and ocular pain. During the early postoperative period, the level of consciousness was better and nausea and vomiting occurred less frequently in the patients operated by the one-stage procedure. Postoperative activity and oral intake returned to normal status more quickly in the one-stage group and the one-stage procedure was cost-effective. CONCLUSION We conclude that although both procedures provide satisfactory and stable results, the one-stage procedure has significant advantages over the two-stage procedure for medial rectus recession surgery in suitable cases.     

Long-term Results of Cryotherapy for Active Stages of Retinopathy of Prematurity

Between 1976 and 1980, retinopathy of prematurity (ROP) stage III (moderate) (fibrovascular proliferation) developed in 29 eyes (confluent fibrovascular proliferation of 3 clock hours in extension) of 17 preterm babies. The eyes were treated by cryopexy to the avascular retina. Analysis of the visual function and anatomic results in these eyes, five to eight years postoperatively, revealed very good visual function and only a few anatomic abnormalities. Comparison of these eyes with those of two groups of age- and birth-weight-matched preterms (one with less severe ROP, not treated by cryopexy, and the other with no ROP) showed that the degree of myopia was significantly higher in the cryotreated group. Although not statistically significant, there was a higher incidence and a greater degree of astigmatism in this study group.     

Primiparity, assisted reproduction, and preterm birth in twin pregnancies: a population based study

Objective To determine the prevalence of pregnancy complications among primiparous patients with twin gestation in our population and to investigate the association between the increased rates of assisted reproduction (ART) in twin gestation and preterm birth (PTD). Material and methods A retrospective population based cohort study was designed, including all twin deliveries after 24 weeks gestation (n = 2,601). The study group included 666 primiparous women and the comparison group 1,935 multiparous women. Maternal characteristics and perinatal outcome were evaluated. Women with fetal malformations were excluded. A multiple logistic regressions analysis for independent risk factors was performed including factors that were significantly different between the study groups in the univariate analysis. Patient’s data were obtained from computerized database and analyzed using SPSS statistical package. Results Primiparous women had a significantly higher rate of preeclampsia, chronic hypertension, ART, prelabor rupture of membranes (PROM) preterm deliveries (PTD), labor dystocia, cesarean section (CS) and vacuum extraction of the first twin than the multiparous group. Primiparous patients had a significantly lower gestational age at delivery and neonatal birth weight of the first and second twin. In multiple logistic regressions analysis primiparity and ART were independent risk factors for PTD, (OR 1.45, 95% CI 1.18–1.78; OR 1.36, 95% CI 1.09–1.71, respectively). Conclusions (1) Primiparous patients with twin gestation represent a unique population with high rate of infertility and underlying diseases such as chronic hypertension in comparison to the multiparous women with twin gestation; (2) primiparity is an independent risk factor for prematurity in twin gestations; and (3) although primiparous women had an increased maternal complications, neonatal mortality rates were not significantly different from multiparous women.     

537名铁路机务人员立体视觉锐度调查报告

本文采用颜氏随机点《立体视觉检查图》,随机调查了537名铁路机务人员的立体视觉情况。其中达到正常立体视锐度阈值≤60秒角者共484名,占全部受检者的90％。立体视觉不良者46名,完全无立体视觉者8名。从而证实了人群中确有少数人患有立体盲或立体弱,故我们认为应把立体视觉检查作为铁路机务人员的体检项目之一。同时,在调查中还发现随着年龄的增加,立体视觉响应速度有所下降,年龄在40岁以上者立体图识别时间较40岁以下者明显延长。故提示人类立体视觉的敏锐性可能随着年龄的增加而有所下降。     

Short-Term Visual Experience Leads to Potentiation of Spontaneous Activity in Mouse Superior Colliculus

Spontaneous activity in the brain maintains an internal structured pattern that reflects the external environment,which is essential for processing information and developing perception and cognition.An essential prerequisite of spontaneous activity for perception is the ability to reverberate external information,such as by potentiation.Yet its role in the processing of potentiation in mouse superior colliculus(SC)neurons is less studied.Here,we used electrophysiological recording,optogenetics,and drug infusion methods to investigate the mechanism of potentiation in SC neurons.We found that visual experience potentiated SC neurons several minutes later in different developmental stages,and the similarity between spontaneous and visually-evoked activity increased with age.Before eye-opening,activation of retinal ganglion cells that expressed ChR2 also induced the potentiation of spontaneous activity in the mouse SC.Potentiation was dependenton stimulus number and showed feature selectivity for direction and orientation.Optogenetic activation of parvalbumin neurons in the SC attenuated the potentiation induced by visual experience.Furthermore,potentiation in SC neurons was blocked by inhibiting the glutamate transporter GLT1.These results indicated that the potentiation induced by a visual stimulus might play a key role in shaping the internal representation of the environment,and serves as a carrier for short-term memory consolidation.     

单绒毛膜双羊膜囊双胎减胎的研究进展

与辅助生殖技术(ART)相关的单卵双胎(MZT)的发生率不断升高。双胎妊娠绒毛膜性的判定可对其风险进行分层。单绒毛膜双羊膜囊(MCDA)双胎围生期具有高发病率和死亡率,其各种减胎方法各有利弊。传统的阴道超声引导下的胚胎组织穿刺抽吸术具有局限性,现主要采用血管闭塞技术用于对MCDA双胎进行选择性减胎,比如脐带双极电凝术和射频消融术等。减胎术的并发症主要有未足月胎膜早破(PPROM)和早产,但有关MCDA的各种减胎方法的时机、适应证及预后等尚未形成统一的标准,故对于减胎术后的新生儿必须进行长期的随访。