Study of Laser Ocular Effect and Damage

In this paper, the characteristics and regularities of acute ocular injuries by direct laser exposure are briefly reviewed, typical cases of ocular injuries from accidental laser exposure are reported, and laser occupational harm to the eye are discussed on the basis of epidemic investigation of personnel engaged in laser work.     

脉络膜挫伤

回顾６４例外伤性脉络膜挫伤。多发于２０－３０岁的青年男性；最常见有拳击伤；临床主要表现为视力下降，眼底可见脉络膜出血灶及裂伤口，荧光眼底血和造影可帮助诊断。脉络膜挫伤多发生于黄斑部，其次为视乳头周围，多为单个，１－ＰＤ大小，脉络膜破裂的形态多为长弧形，脉络膜出血多为圆形；脉络膜破裂与出血常同时出现。     

GABAergic and glycinergic inputs to the rabbit oculomotor nucleus with special emphasis on the medial rectus subdivision

Contradictory results have been reported about the inhibitory input to the medial rectus subdivision of the oculomotor nucleus of the cat. In the present ultrastructural study, we quantified the GABAergic and glycinergic terminals in the various subdivisions of the rabbit oculomotor nucleus with the use of post-embedding immunocytochemistry combined with retrograde tracing of horseradish peroxidase. The density of the GABAergic input to the medial rectus subdivision was as substantial as that to the other subdivisions and the postsynaptic distribution of the GABAergic and glycinergic innervation did not differ among the different oculomotor subdivisions.     

米诺环素对压力作用下体外培养视网膜神经细胞凋亡的抑制

目的 观察米诺环素对压力系统作用下大鼠视网膜神经细胞(RNs)的活性及凋亡的影响，探讨其对受损RNs保护的可能机制。 方法 制备大鼠RNs体外加压培养模型，通过细胞形态学观察、四唑盐（MTT）比色法测定细胞活力、吖啶橙/溴化乙锭（AO/EB）染色法检测细胞凋亡率等方法观察不同浓度的米诺环素对上述损伤细胞的保护作用，并用免疫细胞化学法观察iNOS和caspase 3表达的改变。 结果 加压培养后RNs与对照组相比形态改变较明显，细胞活力降低，5393%的细胞发生凋亡。20000 μmol/L的米诺环素治疗组则细胞形态改善，活力显著增高，1729%的细胞发生凋亡；免疫细胞化学法显示细胞内iNOS和caspase-3表达较加压损伤组减少。 结论 一定剂量的米诺环素在体外可有效抑制压力引起的大鼠RNs损伤及凋亡；抑制iNOS和caspase-3的表达可能是其潜在作用机制。     

眶骨延长术治疗眼球突出的实验研究

目的探讨眶骨延长术扩大眶容积治疗眼球突出的可行性。方法1年龄山羊6只,环行截开右侧眶壁,于眶上壁放置延长器,侧向延长1.5cm,经大体、X线、干骨标本及组织学观察成骨情况。结果6只山羊眶骨得到不同程度的侧向延长,延长侧随着眶骨容量的增加,眼球突度较自身对照侧为小。结论眶骨延长术可造成山羊眶骨侧向移位,有可能成为治疗眼球过度突出的方法之一。     

急性重度眼烧伤135例临床分析

目的了解急性重度眼烧伤的临床特点、预后及并发症发生情况。方法对笔者单位病案室保存的1977--2002年住院眼烧伤患者135例（155只眼）的病历进行回顾性统计分析。分析不同深度、原因眼烧伤的眼表修复率、修复时间、致盲情况及并发症。结果治疗后Ⅲ度眼烧伤的修复时间短于Ⅳ度眼烧伤，其修复率也明显高于Ⅳ度眼烧伤（P〈0．01）；在不能修复的Ⅳ度眼烧伤中，酸烧伤致角膜穿孔6只眼，显著高于碱烧伤（1只眼，P〈0．05）。Ⅲ度眼烧伤视力≥0．05者有38只眼，〈0．05者51只眼；Ⅳ度眼烧伤视力≥0．05者0只眼，〈0．05着66只眼。78只酸、碱烧伤眼中，52只眼致盲，致盲率为66．7％；77只热烧伤眼中，65只眼致盲，致盲率为84．4％。Ⅲ度眼烧伤的并发症发生率低于Ⅳ度眼烧伤。其中Ⅲ度眼烧伤角膜穿孔、睑球粘连的发生率（1．1％、36．O％）均显著低于Ⅳ度眼烧伤（27．3％、59．1％，P〈0．01）。在酸烧伤患者中，角膜穿孔及睑外翻的发生率（29．2％、37．5％）较高。而热烧伤患者中眼睑球粘连的发生率（53．2％）较高。结论Ⅳ度眼烧伤伤后的预后差，致盲率高。目前的治疗方法尚不能完全改善其视功能及预后，有待进一步研究。     

Analysis of saccadic short-term plasticity in three dimensions

The capacity for short-term adaptation is a well-established property of the horizontal (H) and vertical (V) components of saccades. It allows these directional components, which clearly serve the goal of foveation, to maintain their precision even under changing circumstances. Torsional (T) saccade components, on the other hand, which deal with the orientation of the target on the fovea, have hardly been investigated in adaptation experiments. They appear to be severely restricted by Listing's law during fixations and saccades. The main purpose of Listing's law is far from obvious but could be visual or oculomotor. Better knowledge of the adaptive capacity of the saccadic system in the torsional direction could throw new light on the functional significance of this interesting neural strategy. To study short-term plasticity in the torsional components of saccades, binocular 3D-eye positions were measured, using magnetic search foils. Five normal human subjects were instructed to make uni-directional refixation saccades, while they viewed a large visual scene. To induce a change in the torsional component, the complete stimulus was rapidly rotated during these saccades. We thoroughly investigated the torsional responses of the saccadic system, to see if any short-term adaptive response in torsional direction was induced, in which case the notion of a visual purpose for Listing's law would be strengthened. In none of our experiments, however, did we find any clear adaptive response in torsional direction. To further investigate the reliability of this result and to ascertain that our experimental conditions allowed classical gain adaptation, we also did experiments designed to achieve a combination of torsional adaptation and classic gain shortening in one of the directional components. While gain adaptation was very obvious, none of the experiments provided evidence for a short-term effect in torsion. We conclude that our experiments do not support a purely visual basis for Listing's law.     

Retinal specificity in eye fragments: investigations on the retinotectal projections of different quarter-eyes in Xenopus laevis

According to Sperry's chemoaffinity hypothesis, the projection of a small eye fragment with a reduced amount of optic fibres should be restricted to that position in the optic tectum corresponding to its own specificity. However, previous investigations on different types of quarter-eyes in Xenopus laevis have revealed that their retinal projection was always restricted to the rostral part of the tectum, no matter what the origin of the remaining retinal quadrant. To get an indication of the state of specificity in such eye fragments, we investigated by electrophysiological and histological methods several features of the retinal projections of temporoventral (TV), naso-ventral (NV) and ventral (V) quarter-eyes which referred to their positional identity. Irrespective of their different origins, the projections were always located in the rostral part of the tectum, the size of the innervated tectal area depending for all fragment types on the size of the quarter-eyes, i.e. number of optic fibres. However, quantitative analyses revealed that with increasing eye size the various fragments expand their projections preferentially into those tectal areas that match their original specificity: TV projection is more concentrated in the rostral tectum, NV eyes expand their projections mainly to the caudal tectum, and V eyes enlarge their projections equally into the medial and caudal tectum. In addition, fibre-tracing experiments with cobaltic lysine showed that, according to the different origins of the quarter-eyes, retinal fibres follow the appropriate branch of the optic tract selectively: fibres of NV and V eyes pass mainly through the medial tract, and most fibres of TV eyes innervate the rostral tectum directly from a central position between the two side branches. All these findings suggest that the different types of quarter-eyes retain their original positional identity. Thus, their rostrally located retinotectal projections are not in register with their retinal specificity. We conclude that in X. laevis local positional markers in the tectum, if present at all, do not influence the development of the retinotectal projection. Instead we suggest a concept of self-sorting of the optic fibres, which can account for the partial innervation of the rostral tectum in different types of quarter-eyes.     

Human cyclovergence as a function of stimulus frequency and amplitude

Summary By the use of scleral search coils a continuous record of human cyclovergence was obtained while two identical 80° textured patterns, presented dichoptically, oscillated in the frontal plane in counterphase through 1, 3 and 6° of cyclorotation at frequencies between 0.05 and 2 Hz. The amplitude and gain of the response decreased exponentially with increasing stimulus frequency. As stimulus amplitude increased, response amplitude also increased but gain was highest for low-amplitude cyclorotations. For an amplitude of 1° and a frequency of 0.05 Hz the gain reached 0.87 for two subjects. The phase lag increased from a few degrees at a frequency of 0.05 Hz to over 100° at a frequency of 2 Hz. These results suggest that cyclovergence is designed to correct for small, slow drifts in the stereoscopic alignment of the images in the two eyes. Although the disparity in the textured display was not interpreted as slant, it provided a strong stimulus for cyclovergence. The cyclovergence caused a transfer of cyclodisparity into a superimposed vertical line, which was then perceived as slanting in depth.     

眼球破裂伤相关因素分析

目的 观察眼球破裂伤的致伤原因、常见部位、视力预后。方法 眼科住院眼球破裂伤51例的回顾性总结分析。结果 眼球破裂伤的首要致伤因素是打架斗殴(占43％)、其次工伤(占20％)、家庭休闲和旅游误伤(占17％)，交通事故(10％)，其他(10％)。眼球破裂伤的常见部位是上方角膜缘(占45％)，颞侧、鼻侧角膜缘和肌止点后巩膜(各占15％)。经过治疗，Ⅰ度破裂伤7／13获得0．02以上视力，Ⅱ度破裂伤9／20保留光感以上视力，Ⅲ度破裂伤1／18保留光感视力。结论 打架斗殴是眼球破裂伤首要致伤因素，常见伤口位置是上方角膜缘，眼球破裂伤的预后和损伤程度密切相关。