老年人立体视觉的检查与分析

目的 :了解老年人立体视觉状况 ,为其自身保健和自我保护提供参考与帮助。方法 :选用军事医学科学院放射医学研究所和海军总医院最新研制的全息立体视觉检查仪 ,用普查方法对老年人进行立体视觉检查、统计和分析。结果 :与其他年龄人群相比 ,老年人立体视锐度正常人员比例明显降低 (35 .4% ) ,而立体视盲比例明显增加 (12 .4% )。结论 :对老年人进行立体视觉检查十分必要 ,如能根据检查结果采取相应措施 ,将有助于提高他们的生活质量     

未来人工照明:向阳光靠近——人工智能照明与视觉健康

光对于人眼的正常发育和视觉形成起到了至关重要的作用.人工照明所形成的人类新环境是现代社会发展的必然,而涉及眼健康或眼损伤的环境关联因素之一也是人工照明.在未来人工智能照明的科技发展中,如何寻求适宜眼健康的科技方向?综合光与视觉的科学研究和诸多分析观点,作者提出,未来的人工智能照明应该向"阳光"靠近,合理构建光谱组成、模拟自然光节律,并实现可调节化.     

老年性黄斑变性视觉电生理研究

老年性黄斑变性（ＡＭＤ）是西方国家６０岁以上老年人低视力和致盲的首要原因，早期诊断非常重要。近年来国内外许多作采用视觉电生理对ＡＭＤ进行检查，研究证明视觉电生理是一种较好的视功能客观检查方法，在ＡＭＤ的诊断、早期诊断、发病机理、发展过程及预后判断上均具有重要价值。     

重视与体育运动有关的视觉科学研究

体育运动与视觉功能关系密切,不同的体育项目对视觉功能的要求不同.大部分体育项目对视觉的需求都是综合性的,即不仅需要敏锐的视力、立体视、色觉、视野等静态视觉,还需要快速的眼球运动、调节辐辏等动态视觉.优秀运动员必须具备良好的视觉功能,而相关的视觉功能训练可望提高运动成绩.我们应重视并开展体育运动与视觉科学的研究.     

斜视弱视患者的双眼视觉状况及其矫治

本文在复习正常双眼视觉的概念及检查双眼视觉的常用方法和双眼视觉正常范围的基础上,介绍了单眼深度感知和双眼立体视觉近年来神经生理学及神经解剖学的研究进展,即单眼深度线索和双眼深度线索获得的深度感知在顶叶皮层的CIP区（顶尾侧）被整合,强调了单眼及双眼均可感知立体视觉。重点阐述斜视、弱视患者双眼单视及双眼立体视觉受到损害的状况,以及应用脱抑制训练、融合训练、立体视训练等方法矫治双眼视觉缺陷的结果。     

双眼单视功能检查和验光配镜

验光配镜必须检查视力，这一点是配镜者都知道的。但多年来配镜者均习惯于查单眼视觉，而能够查双眼视觉的眼镜店是非常之少的。随着时代的进步，人们早已不能满足于只查单眼视觉了。单眼视觉和双眼视觉的根本不同点在于单眼视觉是两维平面视觉，而双眼视觉是三维立体视觉，是人类的高级视觉功能。有了正常的双眼视觉，人类才可以更好地学习，从事较为精细的工作，正确地判断物体的距离、大小、位置及方向，正确地判断自身与客观环境之间的位置关系。双眼视觉必须建立在单眼视觉的基础之上，但它们之间确又有着质的不同。     

儿童双眼视觉三级功能研究现状与进展

本文首先总结了三级功能的定义与分类,其次阐述了双眼视觉发育和关键期最新研究进展,以及双眼视觉的检查方法现状,最后介绍了双眼视觉研究在儿童斜、弱视的应用现状与进展,从而为儿童双眼视觉三级功能的进一步研究提供参考.     

视觉信息加工的神经机制

外界信息的80%是经视觉系统传人大脑,视觉系统与脑的许多高级功能密切相关,对视觉信息加工机制的研究成为神经科学、认知科学的热门课题.随着脑科学的发展,视觉信息加工机制的研究进入一个崭新阶段.就视觉通道、等级加工、功能特异化、选择性注意、视皮层细胞的同步振荡等进行综述.     

运动视觉及视觉训练的研究进展

运动视觉也称运动视力,是人在运动过程中通过观察环境和事物的变化后,对自己的动作及时做出反馈调整的能力。运动视觉是视觉领域的一个新学科,主要包括评价和提高视觉表现力,对视觉问题进行诊断,并提供必要的视觉训练帮助。视觉训练是一种眼睛和大脑的训练方式,是对大脑视觉神经认知系统的刺激与训练。目前该研究在很多体育运动项目中受到广泛关注,已成为一个新兴热点。运动员的运动视觉能力基本上是在长期的训练和比赛实践中得到增长的,现就其国内外的研究成果作一综述。     

视觉诱发电位与双眼视功能：Ⅱ.视差刺激VEP与立体视

立体视觉作为双眼视功能的最高级形式,已经成为斜视、弱视治疗的最高目标。应用心理物理的方法,对立体视觉进行检查,已经不能满足临床和科研的需要,因此,探索客观评价幼     

Non-standard Vision Measures Predict Mortality in Elders: The Smith-Kettlewell Institute (SKI) Study

Purpose: To determine which vision tests predict mortality within 10 years in a community-based elderly sample.

Methods: Nine hundred residents of Marin County, California 58 to 101 years of age (mean 75 years at baseline), underwent a battery of tests, including high contrast acuity, low contrast acuity, low contrast/low luminance acuity, acuity in glare, contrast sensitivity, color vision, stereopsis, standard and attentional fields. The association between the vision tests and mortality within 10 years of baseline was assessed with Cox Proportional Hazards models controlling for age, sex, education level, depression, cognitive status and self-reported medical conditions.

Results: Forty-three percent of the sample died within 10 years of baseline. When controlling for mortality-related covariates, impairment in any of the vision measures was associated with increased risk of death. However, non-standard vision measures (ie, impairment in low contrast/low luminance acuity, standard field integrity and the impact of the attentional task on field integrity) were more highly associated with mortality than standard high contrast acuity.

Conclusions: In agreement with other studies, we find that visual impairment is a significant predictor of death. However, the strongest relationship was found for measures other than high contrast acuity. These results suggest that non-standard vision measures may be more sensitive indicators of generalized aging in the most elderly.     

The contrast sensitivity of the squirrel monkey (Saimiri sciureus)

The contrast sensitivity of three squirrel monkeys and two human subjects was measured under similar conditions with a modified method of constant stimuli. Sensitivity was greatest for all subjects at 2–5c/deg and declined at higher and lower spatial frequencies. The high frequency limit of resolution was approx 35 c/deg for two monkeys and the human subjects and 17 c/deg for the other monkey. These results agree closely with previous visual acuity measurements for both species when luminance differences are taken into account. At the low photopic luminance used in the present study, the spatial vision of humans and squirrel monkeys appears very similar.     

Comparative effects of luminance and scatter on the pattern visual evoked potential and eye-hand reaction time

We investigated the effect of reduced luminance and increased scatter on the pattern visual evoked potential and eye-hand reaction time evoked to a check size of 0.5° in 10 normal subjects. Data analysis indicated that a reduction in luminance as well as an increase in scatter caused a statistically significant increase in the peak time of the pattern visual evoked potential P₁₀₀ wave. The reaction time, however, was not significantly affected by the initial 0.9-log unit attenuation of the stimulus luminance or the 0.3 scatter filter. Further attenuation of luminance or increase of scatter also yielded statistically significant increases. Our results suggest that the reaction time is less affected by a reduction in luminance or an increase in scatter of a 0.5° stimulus than the pattern visual evoked potential is and therefore represents a more reliable test to assess visual function, especially in the presence of medial opacities, which are known to reduce luminance and produce scatter.     

Age effects on saccadic suppression of luminance and color

Saccadic eye movements modulate visual perception: they initiate and terminate high acuity vision at a certain location in space, but before and during their execution visual contrast sensitivity is strongly attenuated for 100 to 200 ms. Transient perisaccadic perceptual distortions are assumed to be an important mechanism to maintain visual stability. Little is known about age effects on saccadic suppression, even though for healthy adults other major age-related changes are well documented, like a decrease of visual contrast sensitivity for intermediate and high spatial frequencies or an increase of saccade latencies. Here, we tested saccadic suppression of luminance and isoluminant chromatic flashes in 100 participants from eight to 78 years. To estimate the effect of saccadic suppression on contrast sensitivity, we used a two-alternative forced choice (2AFC) design and an adaptive staircase procedure to modulate the luminance or chromatic contrast of a flashed detection target during fixation and 15 ms after saccade onset. The target was a single horizontal luminance or chromatic line flashed 2° above or below the fixation or saccade target. Compared to fixation, average perisaccadic contrast sensitivity decreased significantly by 66% for luminance and by 36% for color. A significant correlation was found for the strength of saccadic suppression of luminance and color. However, a small age effect was found only for the strength of saccadic suppression of luminance, which increased from 64% to 70% from young to old age. We conclude that saccadic suppression for luminance and color is present in most participants independent of their age and that mechanisms of suppression stay relatively stable during healthy aging.     

Comparing continuous and stepwise luminance variation in static campimetry using the Grignolo-Tagliasco-Zingirian projection campimeter

In traditional static perimetry the remarkable precision achieved, resulting mainly from the lack of temporal factors related to latency, largely makes up for the relatively long time required to perform the test. Conversely, the increase in speed of the test and in the information content of the visual field charts counteract the lower precision attained with kinetic perimetry. If the influence of the latency time on responses could be kept at a low value, then adopting a static strategy, based on a continuous rather than discrete target luminance variation for threshold detection, could be justified. For this purpose a luminance variation time sequence designed to reproduce the conditions of the traditional static perimetric test was chosen. The test was performed on the Grignolo-Tagliasco-Zingirian projection campimeter, after comparing its clinical performance with the Goldmann perimeter. These two methods - one based on continuous variation, the other based on discrete target luminance variation - were compared using a 14-subject sample. We conclude that the presentation strategy based on continuous luminance variation can be regarded as a valid alternative to the traditional method.     

三种视力表视力测量差异研究

目的:探讨mc-3投影式视力表(A)、普通箱式视力表(B)以及综合验光仪(C)对不同年龄段人的裸眼视力及校正视力的测量结果是否有差异.方法:志愿者206人(395眼),根据患者年龄分为3组:青年组:25～45岁,共116眼;中年组:46～70岁,共102眼;老年组:71～90岁,共177眼.用视力表投影仪、普通箱式视力表以及综合验光仪分别测量各志愿者的裸眼视力及矫正视力.结果:矫正视力:3组中均无差别.裸眼视力:青年组、中年组中无差别.老年组中综合验光仪的视力测量结果要好于视力表投影仪和视力了表箱,差别具有显著性意义(秩和检验P＜0.05).结论:在老年组的裸眼视力测量结果中,综合验光仪好于视力表投影仪和视力表箱,这种视力测量的差异可能足由于不同背景亮度及视标照度下视标的对比度不同所引起.     

The effectiveness of computer screen filters

We have compared the performance of a variety of computer screen filters which are currently available in Australia. The filters tested included six neutral density filters and 10 mesh filters. The testing incorporated measurements of the filters' effectiveness in reducing the luminance of specular and diffuse reflections, along with an analysis of the effect of the filters on screen luminance/contrast at a variety of viewing angles (from 0^o to 50^o). As groups, the neutral density filters with antireflection coatings and mesh filters performed significantly better than neutral density filters without antireflection coatings in reducing die luminance of specular reflections. For diffuse reflections, die neutral density filters with antireflection coatings performed significantly better than mesh filters in reducing the luminance of die reflections. The performance of mesh filters in reducing specular reflections was significantly positively correlated widi die density of die mesh. All filter types caused reductions in screen luminance and contrast widi increase in off-axis viewing angles.     

Changes in reaction time and search time with background luminance in the mesopic range

Vision relies on both rod and cone signals over a large range of ambient illumination that encompasses a number of common situations. It is important, therefore, to understand how performance changes with light level in functional visual tasks. We measured reaction times and search times using achromatic targets to examine the relationship between latency and luminance contrast as a function of background luminance. Visual search was more robust to changes in luminance than reaction time; search performance could be made invariant by scaling the effects of contrast, but the range of reaction time changed significantly over the mesopic range. We also investigated the extent to which two mesopic visual performance models described the dependence of reaction time and search time on stimulus spectra, using coloured stimuli. The 'effective contrast' model that we examined described the spectral dependence of both reaction time and search time well. A model for mesopic luminous efficiency based on reaction times described the spectral dependence of each response only in conditions where there was little influence of chromatic signals.     

Contrast sensitivity and acuity of the goldfish.

Photopic contrast thresholds to sinusoidal gratings were measured in five goldfish by conditioning respiration in a Pavlovian paradigm. Vertical gratings were generated on an oscilloscope at a space-averaged luminance of 5 and 23 cd/m². The CSF (contrast sensitivity as a function of grating spatial frequence) peaked at about 0.3 c/deg, falling off at lower and higher spatial frequencies. CSF's were fitted by double exponential functions that were used to calculate acuity and point-spread functions. Acuity, defined as the half-period of a just resolvable unity contrast grating, ranged in different fish from 13′ to 22′, the smaller value agreeing with the acuity predicted from the intercone separation. The central region of the derived point-spread function subtended about 1.6°, which is smaller than both the smallest ganglion cell receptive field centers, and the limit of full summation previously found for the light-adapted goldfish.     

Spatial summation in young and elderly observers

We measured detection thresholds for targets over a range of sizes at both photopic and scotopic luminance levels in young and elderly observers, and used these data to estimate spatial summation areas 10 degrees in the retinal periphery. There were differences in detection thresholds between the young and old groups at photopic and scotopic luminances, but no differences in spatial summation areas at either background luminance level.