{"id":{"repo_id":"bradford","oai_identifier":"oai:bradscholars.brad.ac.uk:10454/16833"},"canonical_url":"https://search.dev.ndltd.org/etd/bradford/oai:bradscholars.brad.ac.uk:10454/16833","repository":{"repo_id":"bradford","name":"University of Bradford","base_url":"https://bradscholars.brad.ac.uk/oai/request"},"display":{"title":"The Isolation of Human Rod and Cone Photoreceptor Activity combining Electroretinography and Silent Substitution Techniques","abstract":"Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones. Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function. Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency. Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges.","abstract_html":"Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones. Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function. Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency. Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges.","abstract_has_math":false,"creators":["Maguire, John"],"institution":"University of Bradford","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["McKeefry, Declan J.","Gilchrist, James M."],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017","date_published":"2017","updated_at":"2026-07-24T01:14:32Z","subjects":["Electroretinography","Human vision","Retina","Photoreceptors","Rods and cones"],"languages":["en"],"rights":["\"Creative
The University of Bradford theses are licenced under a Creative Commons Licence."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10454/16833","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["McKeefry, Declan J.","Gilchrist, James M."]},{"key":"dc:creator","label":"Author","values":["Maguire, John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-02-21T16:02:36Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-02-21T16:02:36Z"]},{"key":"dc:date.issued","label":"Date","values":["2017"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Optometry and Vision Science"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Bradford"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Electroretinography","Human vision","Retina","Photoreceptors","Rods and cones"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["\"Creative
The University of Bradford theses are licenced under a Creative Commons Licence."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10454/16833"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones. Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function. Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency. Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges."]},{"key":"dc:title","label":"Title","values":["The Isolation of Human Rod and Cone Photoreceptor Activity combining Electroretinography and Silent Substitution Techniques"]}]}],"canonical_facts":{"dc:contributor.advisor":["McKeefry, Declan J.","Gilchrist, James M."],"dc:creator":["Maguire, John"],"dc:date.accessioned":["2019-02-21T16:02:36Z"],"dc:date.available":["2019-02-21T16:02:36Z"],"dc:date.issued":["2017"],"dc:description.abstract":["Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones. Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function. Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency. Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges."],"dc:identifier.uri":["http://hdl.handle.net/10454/16833"],"dc:language.iso":["en"],"dc:publisher.department":["Department of Optometry and Vision Science"],"dc:publisher.institution":["University of Bradford"],"dc:rights":["\"Creative
The University of Bradford theses are licenced under a Creative Commons Licence."],"dc:subject":["Electroretinography","Human vision","Retina","Photoreceptors","Rods and cones"],"dc:title":["The Isolation of Human Rod and Cone Photoreceptor Activity combining Electroretinography and Silent Substitution Techniques"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-24T01:14:32Z"}