Residual Vision

1989 ◽  
Vol 34 (11) ◽  
pp. 1035-1036
Author(s):  
Herschel W. Leibowitz
Keyword(s):  
Residual Vision

scholarly journals Visual Cortex Transcranial Direct Current Stimulation for Proliferative Diabetic Retinopathy Patients: A Double-Blinded Randomized Exploratory Trial

2021 ◽  
Vol 11 (2) ◽  
pp. 270
Author(s):  
Angelito Braulio F. de Venecia ◽  
Shane M. Fresnoza
Keyword(s):  
Diabetic Retinopathy ◽  
Visual Cortex ◽  
Proliferative Diabetic Retinopathy ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Vision Loss ◽  
Sham Stimulation ◽  
Direct Current Stimulation ◽  
Residual Vision ◽  
Cathodal Tdcs

Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes. PDR-related retinal hemorrhages often lead to severe vision loss. The main goals of management are to prevent visual impairment progression and improve residual vision. We explored the potential of transcranial direct current stimulation (tDCS) to enhance residual vision. tDCS applied to the primary visual cortex (V1) may improve visual input processing from PDR patients’ retinas. Eleven PDR patients received cathodal tDCS stimulation of V1 (1 mA for 10 min), and another eleven patients received sham stimulation (1 mA for 30 s). Visual acuity (logarithm of the minimum angle of resolution (LogMAR) scores) and number acuity (reaction times (RTs) and accuracy rates (ARs)) were measured before and immediately after stimulation. The LogMAR scores and the RTs of patients who received cathodal tDCS decreased significantly after stimulation. Cathodal tDCS has no significant effect on ARs. There were no significant changes in the LogMAR scores, RTs, and ARs of PDR patients who received sham stimulation. The results are compatible with our proposal that neuronal noise aggravates impaired visual function in PDR. The therapeutic effect indicates the potential of tDCS as a safe and effective vision rehabilitation tool for PDR patients.

Man, Monkey, and Blindsight

1998 ◽  
Vol 4 (4) ◽  
pp. 227-230 ◽  
Author(s):  
Tirin Moore ◽  
Hillary R. Rodman ◽  
Charles G. Gross
Keyword(s):  
Visual Cortex ◽  
Visual System ◽  
Primary Visual Cortex ◽  
Visual Function ◽  
Forced Choice ◽  
Neural Mechanisms ◽  
Residual Vision ◽  
Choice Testing

The visual function that survives damage to the primary visual cortex (V1) in humans is often unaccompanied by awareness. This type of residual vision, called “blindsight,” has raised considerable interest because it implies a separation of conscious from unconscious vision mechanisms. The monkey visual system has proven to be a useful model in elucidating the possible neural mechanisms of residual vision and blindsight in humans. Clear similarities, however, between the phenomenology of human and monkey residual vision have only recently become evident. This article summarizes parallels between residual vision in monkeys and humans with damage to V1. These parallels Include the tendency of the remaining vision to require forced-choice testing and the fact that more robust residual vision remains when V1 damage is sustained early in life. NEUROSCIENTIST 4:227–230

Blindsight, Residual Vision

1988 ◽  
pp. 6-6
Author(s):  
Ernst Pöppel
Keyword(s):  
Residual Vision

A Study of Regular Education for Low Vision Children in a Chinese School for the Blind

1989 ◽  
Vol 83 (1) ◽  
pp. 66-68 ◽  
Author(s):  
B. Sun
Keyword(s):  
Optic Atrophy ◽  
Regular Education ◽  
Congenital Cataract ◽  
Low Vision ◽  
Visual Aids ◽  
Residual Vision ◽  
Chinese School

The subjects of this study were 135 pupils of the Shanghai Blind Children's School. Congenital cataract led in the causes of blindness, optic atrophy came second, and microcornea and microphthalmus were third. Among the pupils 74 (54.8%) were totally blind, 56 (41.5%) were low-vision and 5 (371%) had vision of 0.3–0.4. A total of 83 pupils were considered to have usable residual vision for regular education with visual aids. Of the 83, 30 in 3 classes were followed up for two to four semesters, and teaching results were found to be good. None of the students’ conditions deteriorated during that period.

Spatial and temporal response properties of residual vision in a case of hemianopia

1994 ◽  
Vol 343 (1304) ◽  
pp. 157-166 ◽  
Keyword(s):  
Striate Cortex ◽  
Light Flux ◽  
Spatial Summation ◽  
Light Scatter ◽  
Temporal Response ◽  
Rapid Loss ◽  
Residual Vision ◽  
Spatial Frequencies ◽  
Diffuse Illumination ◽  
Peak Sensitivity

Residual vision in subjects with damage of the primary visual cortex (striate cortex) has been demonstrated in many previous studies and is taken to reflect the properties of known subcortical and extrastriate visual pathways. In this report we describe psychophysical experiments carried out on a subject clinically blind in half of his visual field (i.e. homonymous hemianopia) caused by striate cortex dam age. They reveal the existence of two distinct channels mediating such vision. One channel responds to spatial structure and the other to light flux changes. The spatially tuned channel has a peak response at about 1.2 cycles per degree and shows rapid loss of sensitivity at both high and low spatial frequencies. This channel does not respond to diffuse illumination. The light flux channel, however, responds only to sudden increments in light flux levels on the retina and shows extensive spatial summation. Both channels require transient inputs, with a peak sensitivity at about 10 cycles per second and show virtually complete attenuation at temporal frequencies below 2 cycles per second. The spatiotemporal characteristics of these two channels account for much of the reported limits of visual performance attributed to subcortical or extrastriate pathways in some patients, and especially for their relatively good sensitivity for the detection of abrupt, transient stimuli or fast-moving targets. A new method is also applied to the m easurement of the amount of light scatter in the eye. The measurements show that light scatter into the sighted hemifield could not account for the results obtained with the stimuli used to characterize the residual vision of this subject.

Residual vision in a scotoma: implications for blindsight

Science ◽  
1992 ◽  
Vol 258 (5087) ◽  
pp. 1489-1491 ◽  
Author(s):  
R Fendrich ◽  
C. Wessinger ◽  
M. Gazzaniga
Keyword(s):  
Residual Vision
Sign in / Sign up

Export Citation Format

Share Document