scholarly journals Some observations on the relationship between the standing potential of the human eye and the bleaching and regeneration of visual purple

1962 ◽  
Vol 161 (2) ◽  
pp. 205-226 ◽  
Author(s):  
G. B. Arden ◽  
J. H. Kelsey
Keyword(s):  
Standing Potential ◽  
Human Eye ◽  
The Relationship

scholarly journals The Correlations between Horizontal and Vertical Peripheral Refractions and Human Eye Shape Using Magnetic Resonance Imaging in Highly Myopic Eyes

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 966
Author(s):  
Hui-Ying Kuo ◽  
John Ching-Jen Hsiao ◽  
Jing-Jie Chen ◽  
Chi-Hung Lee ◽  
Chun-Chao Chuang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Shape Deformation ◽  
Spherical Equivalent ◽  
Horizontal Meridian ◽  
Resonance Imaging ◽  
Vertical Meridian ◽  
Useful Knowledge ◽  
Human Eye ◽  
The Relationship

The aim of this study was to determine the relationship between relative peripheral refraction and retinal shape by 2-D magnetic resonance imaging in high myopes. Thirty-five young adults aged 20 to 30 years participated in this study with 16 high myopes (spherical equivalent < −6.00 D) and 19 emmetropes (+0.50 to −0.50 D). An open field autorefractor was used to measure refractions from the center out to 60° in the horizontal meridian and out to around 20° in the vertical meridian, with a step of 3 degrees. Axial length was measured by using A-scan ultrasonography. In addition, images of axial, sagittal, and tangential sections were obtained using 2-D magnetic resonance imaging. The highly myopic group had a significantly relative peripheral hyperopic refraction and showed a prolate ocular shape compared to the emmetropic group. The highly myopic group had relative peripheral hyperopic refraction and showed a prolate ocular form. Significant differences in the ratios of height/axial (1.01 ± 0.02 vs. 0.94 ± 0.03) and width/axial (0.99 ± 0.17 vs. 0.93 ± 0.04) were found from the MRI images between the emmetropic and the highly myopic eyes (p < 0.001). There was a negative correlation between the retina’s curvature and relative peripheral refraction for both temporal (Pearson r = −0.459; p < 0.01) and nasal (Pearson r = −0.277; p = 0.011) retina. For the highly myopic eyes, the amount of peripheral hyperopic defocus is correlated to its ocular shape deformation. This could be the first study investigating the relationship between peripheral refraction and ocular dimension in high myopes, and it is hoped to provide useful knowledge of how the development of myopia changes human eye shape.

Research on the Impact of the Contrast between the White Text and Black Background to Visual Sharpness

2013 ◽  
Vol 469 ◽  
pp. 282-285
Author(s):  
Yu Liu ◽  
Shun Yuan Zhang ◽  
Hua Jun Xin
Keyword(s):  
Linear Relation ◽  
Quality Evaluation ◽  
Basic Research ◽  
Objective Measurement ◽  
Print Quality ◽  
Human Eye ◽  
Black Background ◽  
Measurement Results ◽  
The Impact ◽  
The Relationship

This research is to find out the relationship between objective measurement contrast and clarity to the human eye perception, via the analysis of different tone background and white text, based on the text contrast properties in ISO 13660 standard, to do some basic research for the black background of print quality evaluation. Experimental results show that perceived sharpness and contrast into positive correlation, the greater the contrast, the sharpness perception will increase accordingly， but it is not linear relation, in contrast, under the condition of smaller contrast, small changes of contrast will cause great changes in the perception of the definition, with the increase of contrast, perceived definition changes tend to be gentle, it is important to note that contrast is of the biggest objective measurement results in background of 100% black tone, whereas the human eye subjective sense of clarity is not the best, it turns out that the best sense of clarity in background tone value is around 90%.

scholarly journals Changes produced by light in the standing potential of the human eye

1962 ◽  
Vol 161 (2) ◽  
pp. 189-204 ◽  
Author(s):  
G. B. Arden ◽  
J. H. Kelsey
Keyword(s):  
Standing Potential ◽  
Human Eye

COMPLEXITY-BASED ANALYSIS OF THE RELATION BETWEEN MOVING VISUAL STIMULI AND HUMAN EYE MOVEMENT

Fractals ◽  
2019 ◽  
Vol 27 (03) ◽  
pp. 1950024 ◽  
Author(s):  
HEDIEH ALIPOUR ◽  
HAMIDREZA NAMAZI ◽  
HAMED AZARNOUSH ◽  
SAJAD JAFARI
Keyword(s):  
Eye Movement ◽  
Visual Target ◽  
Fractal Theory ◽  
Complex Structure ◽  
Visual Stimuli ◽  
Vision Science ◽  
Human Eye ◽  
Different Types ◽  
External Stimuli ◽  
The Relationship

Investigating human eye movement is one of the major research topics in vision science. It is known that human eye movement is related to external stimuli. In this way, the analysis of human eye movement due to different types of external stimuli is very important in vision science. Beside all reported analysis, no one has discovered any relation between the complex structure of moving visual stimuli and the complex structure of human eye movement. This study reveals the relationship between the complexity of human eye movement signal and the applied visual stimuli. For this purpose, we employ fractal theory. We demonstrated that the fractal dynamics of human eye movement in both horizontal and vertical directions shifts toward the fractal dynamics of moving visual target as stimulus. The capability observed in this research opens new doors to scientists to study the relation between the human eye movement and the applied stimuli.

scholarly journals Cornea donation process and tissue quality for transplantation

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249927
Author(s):  
Giovanna Karinny Pereira Cruz ◽  
Marcos Antonio Ferreira Júnior ◽  
Oleci Pereira Frota ◽  
Elen Ferraz Teston ◽  
Viviane Euzébia Pereira Santos ◽  
...  
Keyword(s):  
Epidemiologic Study ◽  
Tissue Bank ◽  
Corneal Tissue ◽  
Tissue Quality ◽  
Sociodemographic Variables ◽  
Human Eye ◽  
Donation Process ◽  
The Relationship ◽  
Cornea Donation

Introduction The quality of the corneal tissue can be influenced by several factors inherent to the recipient, donor, and to the donation and transplantation process. The donated corneal tissue can be classified by its quality as excellent, good, regular, bad, or unacceptable for transplantation, evaluating it in a slit lamp. Objective To analyze the relationship between the clinical and sociodemographic variables of the donors and the donation process and the classification of the quality of the corneal tissue collected for transplantation. Methods This is an epidemiologic study, retrospective cohort type, which addressed the process of cornea donation by the Human Eye Tissue Bank in a reference service in Northeast Brazil. The sample consisted of corneas processed by the Human Eye Tissue Bank of Rio Grande do Norte (n = 419). For descriptive and inferential analysis, the study used the Statistical Package for the Social Sciences (SPSS) software, version 25.0, and considered a significance level of 0.05. Logistic regression analysis was used for the adjustment of the final model. Results It was verified that the epidemiological profile showed a prevalence of individuals with a mean age of 42.54 years old, male (73.99%), and living in the metropolitan region of the state capital (75.66%). When analyzing the relationship between the clinical and sociodemographic variables of the donors, it was identified that those aged 45 years old or less had better quality corneas (excellent and good), while the chronological variables were predictive factors for corneas of regular and bad qualities. Conclusion The identification of the factors inherent to the donation process and predictors of corneal tissue quality contribute to minimizing the risk of transplantation and to a better ocular prognosis.

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