4th BriSCEV Meeting
4-5th September 2006
Stoke Mandeville Hospital, Aylesbury
Stoke Mandeville Hospital, Aylesbury
Submit an Abstract
To submit an abstract for BriSCEV use the online form below
EXAMPLE ABSTRACT
USING THE LED MULTIFOCAL STIMULATOR TO INVESTIGATE ‘OFF’ RESPONSES AND RESPONSES TO ‘DARK’ STIMULI OR LIGHT DECREMENT STIMULI.
David Keating 1,2, Stuart Parks 1, Donald C.Smith 2, Aled Evans 2
1. Tennent Institute of Ophthalmology, Glasgow, UK
2. Department of Clinical Physics and Bio-Engineering, North Glasgow Hospitals NHS Trust, Glasgow, UK
Purpose : To use multifocal ERG to investigate offset responses and responses to ‘dark’ stimuli or light decrement stimuli.
Methods: It is not possible to obtain Offset multifocal ERG responses from conventional CRT stimulation due to the short luminance ‘on-times’ for each stimulus frame (typically 1- 2 msec of a 13.33 msec frame update time. A custom built LED multifocal Stimulator was used to provide long duration flashes (106 msec) to enable true separation of multifocal ERG onset and offset responses. The use of light decrement or ‘dark’ stimuli in perimetry for detection of glaucomatous field defects has shown promise in recent years 1 . CRT devices do not allow the presentation of such stimuli. In order to present light decrement stimuli the m-sequence ‘0’ state was set to a 13.33 msec period of high luminance and the m-sequence ‘0’ state set to a 1 msec period of low luminance followed by a 12.33 msec period of high luminance.
Results: Long duration stimuli show clear separation of the onset and offset components with the offset response approximately 25% the amplitude of the onset response. Light decrement stimuli produce much smaller responses with amplitudes less than 10% that obtained with standard stimulation. Waveform shape changes are also present with the relative contribution of the N1 component larger and the N2 component smaller for the light decrement stimuli compared to standard light increment stimuli.
Conclusions: Theses techniques enable the study of offset responses in clinical conditions and are of potential interest in conditions such as CSNB and in Glaucoma.
USING THE LED MULTIFOCAL STIMULATOR TO INVESTIGATE ‘OFF’ RESPONSES AND RESPONSES TO ‘DARK’ STIMULI OR LIGHT DECREMENT STIMULI.
David Keating 1,2, Stuart Parks 1, Donald C.Smith 2, Aled Evans 2
1. Tennent Institute of Ophthalmology, Glasgow, UK
2. Department of Clinical Physics and Bio-Engineering, North Glasgow Hospitals NHS Trust, Glasgow, UK
Purpose : To use multifocal ERG to investigate offset responses and responses to ‘dark’ stimuli or light decrement stimuli.
Methods: It is not possible to obtain Offset multifocal ERG responses from conventional CRT stimulation due to the short luminance ‘on-times’ for each stimulus frame (typically 1- 2 msec of a 13.33 msec frame update time. A custom built LED multifocal Stimulator was used to provide long duration flashes (106 msec) to enable true separation of multifocal ERG onset and offset responses. The use of light decrement or ‘dark’ stimuli in perimetry for detection of glaucomatous field defects has shown promise in recent years 1 . CRT devices do not allow the presentation of such stimuli. In order to present light decrement stimuli the m-sequence ‘0’ state was set to a 13.33 msec period of high luminance and the m-sequence ‘0’ state set to a 1 msec period of low luminance followed by a 12.33 msec period of high luminance.
Results: Long duration stimuli show clear separation of the onset and offset components with the offset response approximately 25% the amplitude of the onset response. Light decrement stimuli produce much smaller responses with amplitudes less than 10% that obtained with standard stimulation. Waveform shape changes are also present with the relative contribution of the N1 component larger and the N2 component smaller for the light decrement stimuli compared to standard light increment stimuli.
Conclusions: Theses techniques enable the study of offset responses in clinical conditions and are of potential interest in conditions such as CSNB and in Glaucoma.
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6th BriSCEV Meeting
15-16 September 2008,
Cardiff University
15-16 September 2008,
Cardiff University
Oral presentations will be by Computer projection. Please check the Video projection box if you require the use of VHS video in your presentation.
The abstract should adopt a structured format: Title (block Capitals); Authors names (with presenting author first); author's institutional affiliations; Purpose; Methods;Results; Conclusions and (optionally, Acknowledgements of financial support and the support of any colleagues who are not authors) The abstract should be restricted to 500 words in total.
Please see the sample abstract below
You can type direct onto the form or you can use your preferred word processor and then copy & paste to the box below. It is your responsibility to ensure your abstract is free of typographical errors and is translated in an acceptable English format.
Please see the sample abstract below
You can type direct onto the form or you can use your preferred word processor and then copy & paste to the box below. It is your responsibility to ensure your abstract is free of typographical errors and is translated in an acceptable English format.