立体视锐度与发样十五种元素关系初探

本文采用X－射线荧光分析法测定抚州市区152名健康中小学生（其中立体视锐度异常29人）的头发中Ca、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mg、Pb、Cd、Mo、Se和Ge等15种元素的含量。结果表明立体视锐度异常儿童头发中Se元素含量较正常组低（P＜0．05），而Zn／Cu比值则明显高于正常组（P＜0．05），提示给予富含硒元素的食物，提高体内硒含量，调整Zn／Cu比值．对防治立体视税度导常发生具有重要作用。     

斜视手术前后双眼视觉的临床研究

目的探讨斜视对双眼视觉的影响及不同双眼视检查方法的评价。方法89例共同性斜视分为间歇性外斜、恒定性外斜及恒定性内斜3组。定量测量斜视度；检查双眼视觉状态及视网膜对应情况；测定远近立体视锐度。并观察斜视手术前及手术后1周、1月的斜视度、双眼视觉状态及远、近立体视锐度变化。结果3组术后双眼视功能较术前均有明显改善（P〈0．05），术后1周与1月双眼视功能的差异无统计学意义（P〉0．05）；恒定性斜视术后立体视恢复好于间歇性外斜视，且近立体视恢复好于表视；立体视检查非随机点画片（Titmus与Optec3500）与随机点画片（TNO）检查结果的差异有统计学意义（P〈0．05）；线状镜较Worth四点检测阳性率高；大于9岁患者术后双眼视觉较术前增加32％。结论斜视手术是恢复、重建双眼视觉的有效方法，不同检测方法结果不一致，需综合考虑。     

弱视患儿视力正常后立体视觉的临床观察

目的观察弱视患儿视力正常后立体视觉的状况及影响因素。方法对57例门诊治疗的弱视患儿在视力恢复正常时用同视机行远立体视、用颜少明等的《立体视觉检查图》行近立体视检查,并记录其初诊时的年龄、视力、屈光状态、弱视的类型、治疗过程和持续时间、治愈时的年龄等,分析这些因素与患儿远、近立体视觉的关系。结果57例患儿中,①平均初诊年龄(60.22±15.95)个月(约2～7岁)。②视力正常时平均年龄(84.18±17.28)个月(约4～10岁)。③从开始治疗到视力恢复正常平均(23.56±15.50)个月(约3个月～6年)。④用同视机检查55例,具有Ⅰ级功能(同时视)者1例,Ⅱ级功能(融合)者10例,Ⅲ级功能(立体视)者39例,无功能者5例。⑤行近立体视检查56例,800"不能辨认者16例,800"者5例,600"者2例,200"者2例,100"者10例,60"者7例,40"者14例。⑥在远、近立体视的形成上,患儿的初诊年龄之间无显著差异(χ2=4.773,P=0.092;χ2=0.069,P=0.966);患儿的治疗时间之间无显著差异(χ2=1.848,P=0.397;χ2=1.916,P=0.384);弱视类型之间有显著差异(χ2=12.454,P=0.006;χ2=17.084,P=0.001),即屈光不正性和子午线性弱视预后好,斜视性和屈光参差性弱视预后差。⑦在远立体视形成上,患儿视力正常时的年龄之间(χ2=0.643,P=0.725)和患儿的屈光度之间(χ2=3.045,P=0.218)无显著差异;而在近立体视形成上,患儿视力正常时的年龄之间(χ2=11.41,P=0.003)和患儿的屈光度之间(χ2=8.073,P=0.018)有显著差异,即年龄大(≥8岁)、屈光不正度数大(≥6.25D)者预后差。结论在平均初诊年龄小于5岁,治愈年龄小于7岁的本组57例视力正常后的弱视患儿中39例获得远立体视,21例获得近立体视。年龄大、屈光度数大者可获得远立体视,但近立体视恢复困难。     

立体视正常值变化观察

目的:比较Frisby、Randot、Howard-Dolman三种立体视检查方法的可重复性,确定此三种临床用立体视检查方法的正常值变化的95%可信区间.方法:选择26位无斜视、弱视和眼手术史的健康个体,平均年龄为24.42±4.26岁(14～32岁),所有的受检者具有正常的双眼视且双眼视力为6/6.测量视远瞳距和习惯视力后,以随机的顺序用Frisby、Randot、Howard-Dolman三种检查方法测量立体视,测量时保持光照度为670lx.约1周后在相同的测量条件下同样用三种检查方法测量立体视,平均间隔时间为7.8±2.4天.结果:三种临床立体视检查方法的可重复性系数分别为±2.7"(Frisby)、±8.0"(Randot)和±9.3"(Howard-Dolman),再次试验的平均值低于首次试验的平均值,t检验提示这改变差异无显著性意义(P>0.05).重复试验的相关系数分别为0.91(Frisby)、0.56(Randot)、0.60(Howard-Dolman).三种检查方法之间的相关系数分别为0.31、0.31、0.33.结论:三种临床立体视检查方法的相关性较差.Frisby检查法有最好的重复性和正常值有较小的范围.用该法测得成年人立体视改变的95%可信区间为±2.7".如果用Frisby法测得年轻成年人的立体视的变化超过这个范围,可认为是有显著意义的临床改变.     

中心性浆液性脉络膜视网膜病变患者远近立体视功能

目的 :比较“中浆”患者远近立体视功能损害的临床特点。方法 :对 48例 (5 1眼 )中浆患者按常规方法检查视力、屈光、Amsler方格卡、双眼影像、眼底FFA或OCT ;用同视机检查患者双眼同时知觉、融合范围及定性立体视 ;采用同视机随机点画片及《立体视觉检查图》检测患者的远近立体视功能及抑制性暗点。结果 :48例患者除中心视力下降、视物变形和有中心暗点等单眼视功能受损外 ,还有双眼影像不等及双眼视功能不同程度的损害。双眼视功能受损中 ,双眼同时视障碍为 2 .1% ,双眼融合视缺失为 4.3% ,而双眼定性立体视丢失为 16 .7%。采用随机点画片定量检测发现 ,远距离交叉视差锐度和非交叉视差锐度及近距离立体视锐度达到正常者分别为 2 8例 (占 5 8.3% )、2 4例 (占 5 0 .0 % )和 14例(占 2 9.2 % )。显示近立体视损害较远立体视更明显 ,差异有显著性 (P <0 .0 5 )。病愈后三项功能恢复中心立体视者分别为 47例 (占 97.9% )、46例 (占 95 .8% )和 45例 (占 93.8% )。病愈前后远近距离三项立体视锐度达到正常者的比例以及平均视锐度值 ,差异有显著性 (P <0 .0 1)。影响立体视功能的主要原因是两眼视力相差大 ,双眼同时视像差大及有抑制性中心暗点。结论 :中浆患者视功能受损表现是多方面的。双眼视功能受损特     

Visual mechanisms governing the perception of auto-stereograms

Background: Single image random dot stereograms (SIRDS) have been used to study diverse visual parameters and skills. The aim of the present study was to identify the main optometric factors involved in the perception of SIRDS and to obtain a discriminant model to categorise our participants in terms of their skill in perceiving SIRDS. Methods: Response time was determined to assess the ability of 69 participants to perceive the hidden three‐dimensional shape in an auto‐stereogram presented under controlled conditions, whereupon three skill level groups were defined. The same participants were administered a battery of optometric tests to evaluate various aspects of accommodation and convergence, as well as stereopsis and phoria. Linear discriminant analysis, which served to examine the relationship between response times and the evaluated visual parameters and skills, provided a set of discriminant functions (or model), thus allowing for the categorisation of participants according to their skill to perceive SIRDS. Results: Two discriminant functions were obtained, which allowed for an overall predictive accuracy of 66.67 per cent (p = 0.024), with a higher predictive accuracy for groups 1 (minimum time less than 10 seconds, 78.26 per cent) and 2 (minimum time greater than 10 seconds, 75.86 per cent) than for group 3 (SIRDS not perceived, 35.29 per cent). Stereoacuity, negative relative convergence, phoria at near and, to a lesser extent, the accommodative convergence and accommodation ratio were found to be the most relevant discriminant variables, although between‐group statistically significant differences were only disclosed for stereoacuity (p = 0.001) and negative relative convergence (p = 0.003). Conclusion: The ability to perceive SIRDS was related to many visual parameters and skills, including, but not limited to, stereoacuity and negative relative convergence. It is uncertain whether SIRDS might be considered a useful tool in clinical practice.     

Effects of practice and the separation of test targets on foveal and peripheral stereoacuity

The improvement in stereoacuity of two inexperienced, normal subjects was compared at foveal and at 2.5 degrees and 5 degrees peripheral target locations as a function of practice. Outlines of two squares differing only in binocular disparity were used as test stimuli and estimates of stereoacuity were obtained by application of the method of constant stimuli with feedback. The peripheral thresholds of both subjects improved 60-80% over the course of the first 3000-4000 responses at each stimulus location. Foveal improvement followed an identical time-course with a 73% improvement in one subject and only 23% in the other. This difference was reflected in the peripheral/foveal threshold ratios of the two subjects and underlines the necessity of ensuring the stability of thresholds. Stereoacuity measurements were also obtained using several different square separations at the fovea and at 2.5 degrees, 5 degrees and 10 degrees peripheral locations along the horizontal and vertical retinal meridians of two other normal subjects. Practice-stabilized disparity thresholds using optimal target separations revealed a steeper deterioration between the fovea and 2.5-5 degrees eccentricities than did measurements of the same subjects' minimum angles of resolution (MAR). The decrease of optimal stereoacuity at the more peripheral test locations was more gradual than has been previously reported but was not clearly related to that of the MAR.     

数显补色照片体视仪的初步临床应用

介绍一种新设计的近距离立体视检测工具－－数显补色照片体视仪。同时应用该仪器对１１３名学生进行近距离立体视锐度测定。结果表明：该仪器具有极高的精密度、正确度和精鸪。该仪器用红－绿蓝颜色互补原理形成双眼视觉分离效果，从零点开始作逐渐增大的立体视镜度测定。其主要特点为：①可测的最小立体视锐度为１０秒。②可测的最大立体视锐度在１０００秒以上。③可连续性测量。④便于临床医师携带应用。     

Correlation between Depth Perception by Three-Rods Test and Stereoacuity by Distance Randot Stereotest

Background: The examination of depth perception with three-rods test, in addition to visual acuity testing, is required to obtain motor vehicle license to drive taxies and trucks, according to the Road Traffic Act in Japan. The aim of this study was to examine whether the results of the three-rods test would correlate with the results of static stereopsis tests, used in ophthalmic practice.

Methods: This study involved 54 normal subjects, 9 women and 45 men, with ages ranging from 18 to 25 (mean, 20.8) years. All had visual acuity of 0.8 or better with or without glasses or contact lenses correction and had no strabismus at the distant (5?m) or near (0.3?m) fixation. TNO Stereotest and Titmus Stereotest were examined at 40?cm while Distance Randot Stereotest was at 3?m. At three-rods test, a central rod was moved at the speed of 50?mm/sec forward and backward automatically against two laterally located fixed rods, placed inside the illuminated box. An examinee at the distance of 2.5?m observed the rods inside the box from a small viewing window and pushed a button to stop the central rod in alignment with the fixed rods. Erred distance (mm) of the central rod from the fixed rods as a mean of 4 measurements was correlated with stereoacuity in second of arc, measured by three kinds of the stereopsis tests.

Results: The erred distance of three-rods test was positively correlated with static stereoacuity at distance measured with Distance Randot Stereotest (ρ?=?0.418, p?=?0.0023, Spearman rank correlation test) and also with the other stereopsis tests at near fixation. The stereoacuity at near fixation, measured by TNO Stereotest and Titmus Stereotest, was positively correlated with each other (ρ?=?0.431, p?=?0.0017).

Conclusion: Three-rods test, examining depth perception, together with the response by eye-hand coordination, gave consistent results with distant static stereoacuity when measured with Distance Randot Stereotest.     

间歇性外斜视的控制力评估及其立体视觉

间歇性外斜视在我国发病率高,病因不明.本文着重从间歇性外斜视控制力的评估及立体视的研究进展进行综述.以神经可塑性原理和知觉训练为切入点,依据背流、腹流通路的相关原理进行干预,有助于改善间歇性外斜视患者的双眼视功能和生活质量,使间歇性外斜视患者达到功能治愈.