ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTThis study shows that the loss of contrast sensitivity in the amblyopic eye does not result from abnormal spatial frequency selective channels. Knowledge of the sine-wave sensitivity of the amblyopic eye may allow accurate predictions of the detection threshold for more complex stimuli. More effective amblyopia treatment strategies may be designed when the amblyope's sensitivity to spatial contrast and relative phase are better understood.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTColor vision loss can be an early sign of eye disease; in many retinal disorders the loss precedes any change in visual acuity. Nonin-vasive psychophysical methods allow factoring out of preretinal, receptoral, and postre-ceptoral (neural) components of the color vision change. A loss of chromatic but not achromatic sensitivity occurs for diabetics; the loss is selective for pathways subserving blue-sensitive photoreceptors. Both chromatic and achromatic pathways are altered in glaucoma and senile macular degeneration; the most marked change in central serous choroido-pathy is loss of sensitivity somewhere in the blue-sensitive cone pathway. There is evidence that the pathways subserved by blue-sensitive cones have anatomically and physiologically different properties from those served by other receptor types, and they appear particularly vulnerable to disturbances of retinal integrity.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTThe contrast sensitivity function provides a more comprehensive and sensitive measure of spatial vision than does visual acuity. A large-sample study of contrast sensitivity during the adult years revealed that observers over age 60 have a substantial loss of sensitivity to intermediate and high frequencies. All observers wore their best possible optical correction for the test distance and were free from significant ocular pathology. We further report that older observers have difficulty perceiving faces under low contrast conditions, which is predictable from the characteristics of their contrast sensitivity functions.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTThis article describes several different psychophysical strategies that have been applied to the study of binocular vision in normal persons and people with deficient stereopsis. Results from these three techniques—binocular summation, interocular transfer, and utrocular discrimination—are considered in terms of the properties of neural mechanisms that integrate inputs from the two eyes.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTMeasurements of central and peripheral corneal thickness, corneal topography, and central corneal curvature were made for 21 subjects at hourly intervals for 12 hr of 1 day for each subject. Values for corneal radius and asphericity were obtained from keratometry and photokeratoscopy, and their stability throughout the day was evaluated. Corneal radius was observed to steepen during the day, whereas asphericity remained constant. Corneal thickness was measured by pachometry and was found to be at its thickest on first awakening. Corneal curvature and central corneal thickness were highly correlated; low correlation was found between corneal asphericity and central corneal thickness. Some subjects exhibited large fluctuations in one or all of the parameters considered.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTIn a previous study we showed that subjects with abnormal binocular vision either lacked or had a deficient ability to adapt their oculomotor systems to a prism-induced heterophoria. In this study we report on the results of an experiment designed to establish whether the adaptation ability improves in patients who are successfully treated, by means of orthoptics, for convergence insufficiency. In all seven patients examined, we found an improved ability to adapt. Whereas at the beginning of the experiment only two patients fell within the 95% confidence limits of the norm, at the end five patients fell within these limits. These results demonstrate that the success of orthoptics in relieving symptoms is associated with an improved ability to adapt to prism-induced heterophoria.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTThe speed of visual processing in the sighting-dominant and nondominant eyes was assessed using a simultaneity procedure in which an auditory target was set to apparently coincide with the onset of a visual stimulus. Under two types of monocular testing, the information from the sighting dominant eye was processed approximately 14 msec faster than the information from the nonsighting eye. These results suggest that the monocular channels are not completely interchangeable, and that response characteristics may vary as a function of sighting dominance.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

ABSTRACTA system was designed to permit simultaneous viewing of the ocular fundus of the rhesus monkey (Macaca mulatta), the accurate placement of laser radiation on the retina, and the stimulation of the site to produce a grating visual evoked cortical potential (VECP). A fundus camera was modified to incorporate a grating whose image was projected onto the retina at specific locations. The evoked potential could thus be obtained for any rate of alternation before, during, and after the exposure of the fovea to any one of many laser sources. An example is shown of the use of this system to monitor the grating VECP before and after exposure of the animal's fundus to a 900 nm gallium arsenide laser source for 60 sec. In this case, changes were observed in the variability of the latency of components of the VECP when compared to the prelaser exposure potentials.

ISSN:0093-7002    

出版商:OVID    

年代:1982

数据来源: OVID