首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15篇
  完全免费   1篇
  眼科学   16篇
  2018年   1篇
  2015年   3篇
  2014年   2篇
  2003年   1篇
  1998年   1篇
  1993年   1篇
  1992年   1篇
  1988年   1篇
  1986年   2篇
  1981年   2篇
  1974年   1篇
排序方式: 共有16条查询结果,搜索用时 115 毫秒
1.
In three of the five achromats examined psychophysically, evidence of three plateaux was found at certain areas of the retina during the normally photopic phase of dark adaptation while the scotopic plateau was normal. These high intensity plateaux coincided fairly well with the photopic phase of our standard dark adaptation curve and the fourth plateau with its scotopic phase. This points to three photopic submodalities and to a normal scotopic mechanism in these achromats. However, the spectral sensitivities, both in the retinal periphery and in the fovea, were maximal between 500 nm and 510 nm for the three photopic plateaux and for the scotopic one and fitted satisfactorily with the 1951 CIE scotopic standard. The mechanisms underlying the appearance of the up to three fast, high-intensity plateaux in the achromats' dark adaptation curves do not fulfill normal requirements completely since they are photopic as to the kinetics of their recovery and scotopic as to their spectral luminous efficiency. The data from the subjects examined indicate three types of receptors with cone kinetics during dark adaptation but containing rhodopsin. The theoretical significance of the findings is discussed, especially why rhodopsin seems to regenerate faster in cones than in rods or in the test tube. Other cases were found, one only illustrated, with only one fast high-intensity plateau similar to those described in the literature.Supported by Stiftung Volkswagenwerk under contract number 11 1538.The Vision Research Laboratory, Hadassah University Hospital and Medical School, Israel.  相似文献
2.
A 45 year old man was studied who was previously diagnosed as a typical achromat. Increment spectral sensitivity measurements on white and several colored backgrounds showed that he possessed a rod system, a cone system sensitive in the short wavelength region (blue cones) and a cone system sensitive in the long wavelength region (red cones). This investigation shows that rather extensive testing is required to classify incomplete achromats.  相似文献
3.
Children with congenital achromatopsia possess an interesting paradoxical pupillary constriction to darkness that has not been previously described. This paper describes three children in whom this paradoxical pupillary reaction was documented with infrared pupillometry. The literature on the pupil in achromatopsia is reviewed and a tentative testable model of the reaction is hypothesized.This work was supported in part by Public Health Service Institutional National Research Study Award # EY 07021 from the National Institutes of Health, Bethesda, Maryland and National Institutes of Health Research Grant 1236-03-04.  相似文献
4.
Two patients presented with unusual uniocular electroretinographic (ERG) phenomena. One patient showed the ERG characteristics of stationary night blindness in one eye only and the other patient presented with ERG evidence of uniocular cone dysfunction. In both patients, however, further electrophysiological and psychophysical studies and serial testing provided evidence for dysfunction of both receptor systems and relatively subtle involvement of the fellow eyes.  相似文献
5.
In three children with achromatopsia light-induced oscillations of the standing potential and electroretinograms (ERGs) were recorded. A low drift direct current recording system was applied to monitor the changes of the standing potential under general anesthesia. In all children the scotopic ERG components were normal. No photopic components could be observed. The fast oscillations of the standing potential were normal under scotopic and photopic conditions. The light-induced slow increase of the standing potential displayed low amplitudes and normal peak latencies. The results of our study support earlier investigations suggesting that cone-mediated mechanisms in the retina contribute a significant component to the amplitude of the light peak in the electroretinogram.  相似文献
6.
In congenital total color blindness direct current recordings of the electroretinogram displayed a negativity following the b-wave, not present in recordings of normal eyes. This negativity, preceding the onset of the c-wave, is probably caused by the lack of cone contribution to the positive c-wave component.  相似文献
7.
The Berson test for blue cone monochromatism discriminates X-linked blue cone monochromatism from achromatopsia but not from X-linked progressive cone dystrophy.  相似文献
8.
Pathologic scotopization, an important symptom of retinal disease, can be studied by means of the Nagel II anomaloscope. This method is called the micro-screw method. The micro-screw method was performed in 14 congenital and 13 acquired colour vision defective individuals. The method proves to be useful in detecting symptoms of rod intrusion in colour vision under photopic conditions.  相似文献
9.
We report on a family where four of the eleven children presented with reduced visual acuities, a red-green deficit at the Farnsworth-Munsel FM 100-hue test, normal appearing fundi and unexpected electroretinographic findings. Light- (photopic) and dark- (scotopic) adapted electroretinograms (ERG) and oscillatory potentials (OPs) were obtained following an accepted standard protocol. The b-wave of their photopic ERG was significantly more attenuated than the a-wave due to the specific abolition of OP4, while the amplitudes of OP2 and OP3 were within the normal range, giving to the b-wave a truncated appearance reminiscent of that seen in congenital stationary night blindness (CSNB) with myopia. Interestingly in the latter condition, which is believed to result from an ON-retinal pathway anomaly, it is OP2 and OP3 which are specifically abolished while OP4 is of normal amplitude thus resulting in an OP response pattern which complements that seen with our patients. Also of interest is the fact that, in our patients, the amplitude of the dark-adapted OP2 was, on average, 240% larger than that measured in light-adaptation while, in normal, a non-significant 14% increase is noted; a finding which is in keeping with other studies reporting supernormal scotopic ERGs in some forms of cone dystrophies. Based on the photopic OP response pattern, our patients represent the electrophysiological complement of patients affected with CSNB. Interestingly their symptoms are also complementary, a finding which could support a functional discrimination between the photopic OPs. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献
10.
A patient describing himself as totally color blind was ordered by the judicial system to have his color vision investigated in order to establish his suitability for military service. Basic clinical (Farnsworth Panel D-15, Moreland and Rayleigh anomaloscope equations), electroretinographic (ERG) and psychophysical techniques (spectral sensitivities) were applied to determine the extent of his color discrimination performance and cone function. These standard procedures were complemented by a test for cone interaction (transient tritanopia) and by newly developed cone-isolating flicker large-field ERG recordings. The patient's data consistently indicate the function as well as the functional interaction of the middle-wavelength-sensitive (M-) and the short-wavelength-sensitive (S-) cones. But the function of the long-wavelength-sensitive (L-) cones was completely absent. Hence the patient was correctly demonstrated to be a protanope. This study establishes that standard classical procedures, in combination with newly developed and easy to apply psychophysical and ERG ones, which can be reliably used to assess true color discrimination performance, in difficult cases of malingering.  相似文献
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号