scholarly journals The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus

2019 ◽  
Vol 60 (1) ◽  
pp. 218 ◽  
Author(s):  
Safal Khanal ◽  
Philip R. K. Turnbull ◽  
Nicholas Lee ◽  
John R. Phillips
Keyword(s):  
Global Flash

scholarly journals The Cellular Origins of Chick Global Flash Multifocal Electroretinogram

i-Perception ◽  
10.1068/ic304 ◽  
2011 ◽  
Vol 2 (4) ◽  
pp. 304-304
Author(s):  
Patrick W. K. Ting ◽  
Patrick H. W. Chu ◽  
Yf Ng ◽  
Henry H. L. Chan
Keyword(s):  
Multifocal Electroretinogram ◽  
Global Flash

scholarly journals Porcine global flash multifocal electroretinogram: Possible mechanisms for the glaucomatous changes in contrast response function

2008 ◽  
Vol 48 (16) ◽  
pp. 1726-1734 ◽  
Author(s):  
Patrick H.W. Chu ◽  
Henry H.L. Chan ◽  
Yiu-fai Ng ◽  
Brian Brown ◽  
Andrew W. Siu ◽  
...  
Keyword(s):  
Response Function ◽  
Multifocal Electroretinogram ◽  
Global Flash ◽  
Contrast Response Function ◽  
Contrast Response

scholarly journals Local Relationship between Global-Flash Multifocal Electroretinogram Optic Nerve Head Components and Visual Field Defects in Patients with Glaucoma

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chan Hee Moon ◽  
Jungwoo Han ◽  
Young-Hoon Ohn ◽  
Tae Kwann Park
Keyword(s):  
Optic Nerve ◽  
Visual Field ◽  
Optic Nerve Head ◽  
Visual Field Defect ◽  
Multifocal Electroretinogram ◽  
Visual Field Defects ◽  
Global Flash ◽  
Field Defect ◽  
Normal Controls ◽  
Field Defects

Purpose. To investigate the local relationship between quantified global-flash multifocal electroretinogram (mfERG) optic nerve head component (ONHC) and visual field defects in patients with glaucoma.Methods. Thirty-nine patients with glaucoma and 30 normal controls were enrolled. The ONHC amplitude was measured from the baseline to the peak of the second positive deflection of the induced component. The ONHC amplitude was normalized by dividing ONHC amplitude by the average of seven largest ONHC amplitudes. The ONHC amplitude ratio map and ONHC deficiency map were constructed. The local relationship between the ONHC measurements and visual field defects was evaluated by calculating the overlap between the ONHC deficiency maps and visual field defect plots.Results.The mean ONHC amplitude measurements of patients with glaucoma (6.01±1.91 nV/deg2) were significantly lower than those of the normal controls (10.29±0.94 nV/deg2) (P<0.001). The average overlap between the ONHC deficiency map and visual field defect plot was 71.4%. The highest overlap (75.0%) was between the ONHC ratios less than 0.5 and the total deviations less than 5%.Conclusions.The ONHC amplitude was reduced in patients with glaucoma compared to that in normal controls. Loss of the ONHC amplitude from the global-flash mfERG showed a high local agreement with visual field defects in patients with glaucoma.

scholarly journals Importance of aerosols for annual lightning production at global scale

2014 ◽  
Vol 14 (4) ◽  
pp. 4303-4325 ◽  
Author(s):  
S. Venevsky
Keyword(s):  
Land Surface ◽  
Cloud Condensation Nuclei ◽  
Global Scale ◽  
Regional Studies ◽  
Ice Crystal ◽  
Tropical Africa ◽  
Cloud Droplets ◽  
Flash Rate ◽  
Global Flash ◽  
Ice Multiplication

Abstract. Lightning production is described using thermodynamic hypotheses mainly according to convective activity in the atmosphere. However, existing formal thermodynamic descriptions are unable to fully explain the profound difference in the flash rate between tropical Africa and South America and between land and ocean. Aerosols are shown to be regulators of lightning in regional studies, but their influence on lightning production at the global scale is not described. I analyzed spatial patterns of the satellite annual global flash rate and simulated, annually averaged cloud condensation nuclei (CCN) distribution and found consistent positive correlation between them for land, ocean and continents. I developed a simple model of lightning production that is based solely on an aerosol hypothesis. The central premise of this model is that concentration of graupel pellets and concentration of ice crystals, which both determine flash rate, are monotonically increasing by CCN concentration up to a critical value (around 2000 cm−3). However, ice crystal concentration falls rapidly after the threshold due to lowering in the number of large cloud droplets effective for rime-splintering ice multiplication. Comparison of the model with a model of the flash rate based on thermodynamic hypotheses demonstrates that the aerosol hypothesis explains the global annual spatial distribution of lightning production consistently better over land and over oceans. My results emphasize importance of aerosols for lightning production and point to the existence of a global aerosol-lightning feedback, which affects both the climate system and the land surface.

Impact of a Digital Power Line Filter in the 2-Global-Flash Multifocal Electroretinogram of Glaucoma Patients Compared to Controls

2015 ◽  
Vol 41 (1) ◽  
pp. 70-78
Author(s):  
Anna A. Ledolter ◽  
Margarita G. Todorova ◽  
Andreas Schoetzau ◽  
Anja M. Palmowski-Wolfe
Keyword(s):  
Multifocal Electroretinogram ◽  
Power Line ◽  
Global Flash

scholarly journals Human Electroretinal Responses to Grating Patterns and Defocus Changes by Global Flash Multifocal Electroretinogram

PLoS ONE ◽  
2015 ◽  
Vol 10 (4) ◽  
pp. e0123480 ◽  
Author(s):  
Man Pan Chin ◽  
Patrick H. W. Chu ◽  
Allen M. Y. Cheong ◽  
Henry H. L. Chan
Keyword(s):  
Multifocal Electroretinogram ◽  
Global Flash

Global‐flash mfERG responses to local differences in spherical and astigmatic defocus across the human retina

2019 ◽  
Vol 40 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Philip R K Turnbull ◽  
Lucy K Goodman ◽  
John R Phillips
Keyword(s):  
Human Retina ◽  
Global Flash
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