{"title":"The consequence of modulating background on the luminance-response function of the human photopic electroretinogram.","authors":"Jan Kremers, Cord Huchzermeyer, Avinash J Aher","doi":"10.1007/s10633-025-10029-y","DOIUrl":null,"url":null,"abstract":"<p><strong>Purpose: </strong>To study the consequences of a modulating background on the luminance-response function of the human photopic flash electroretinogram for different relative timings of the flash relative to the background luminance.</p><p><strong>Methods: </strong>Seven healthy subjects (age: 29-63 years; four females) participated in the study. We measured the response to flashes (9 flash strengths in total between 0.12 and 29.76 cd.s/m<sup>2</sup> while doubling the strength at each step; 5 ms flash duration) on a steady background (24 cd/m<sup>2</sup>) and on a 1 Hz modulating background (24 cd/m<sup>2</sup> mean luminance; 100% contrast). The flashes were presented at 6 different phases during the sine wave (0°, 90°, 180°, 225°, 270°, and 315°). Responses to a 1 Hz sinusoidally modulating stimulus were subtracted from the responses to the combined flash plus sine-wave stimuli to obtain the flash ERGs at different phases.</p><p><strong>Results: </strong>The a-wave and PhNR amplitudes monotonically increased with increasing flash strength. The b- and i-wave amplitudes displayed a maximum at 1.9 cd.s/m<sup>2</sup>, above which they decreased again (the so-called \"Photopic hill effect\"). The responses could be described by an addition of a logistic growth and a Gaussian. The parameters of these functions depended on the time of flash presentation relative to the background. The dependency of the a-, b- and i-wave on flash presentation time with constant flash strength could be described by a model that assumes that the amplitude depends on the Weber fraction of the flash including a delay and a saturation.</p><p><strong>Conclusions: </strong>The use of modulating backgrounds may increase the signal-to-noise ratio of flash ERGs and thus its diagnostic value. The dynamics of the response as a function of flash presentation time gives additional information about the retinal processing of flash and background. The photopic hill model allows the separation of processing in retinal On- and Off-pathways.</p>","PeriodicalId":11207,"journal":{"name":"Documenta Ophthalmologica","volume":" ","pages":""},"PeriodicalIF":2.6000,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Documenta Ophthalmologica","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s10633-025-10029-y","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"OPHTHALMOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Purpose: To study the consequences of a modulating background on the luminance-response function of the human photopic flash electroretinogram for different relative timings of the flash relative to the background luminance.
Methods: Seven healthy subjects (age: 29-63 years; four females) participated in the study. We measured the response to flashes (9 flash strengths in total between 0.12 and 29.76 cd.s/m2 while doubling the strength at each step; 5 ms flash duration) on a steady background (24 cd/m2) and on a 1 Hz modulating background (24 cd/m2 mean luminance; 100% contrast). The flashes were presented at 6 different phases during the sine wave (0°, 90°, 180°, 225°, 270°, and 315°). Responses to a 1 Hz sinusoidally modulating stimulus were subtracted from the responses to the combined flash plus sine-wave stimuli to obtain the flash ERGs at different phases.
Results: The a-wave and PhNR amplitudes monotonically increased with increasing flash strength. The b- and i-wave amplitudes displayed a maximum at 1.9 cd.s/m2, above which they decreased again (the so-called "Photopic hill effect"). The responses could be described by an addition of a logistic growth and a Gaussian. The parameters of these functions depended on the time of flash presentation relative to the background. The dependency of the a-, b- and i-wave on flash presentation time with constant flash strength could be described by a model that assumes that the amplitude depends on the Weber fraction of the flash including a delay and a saturation.
Conclusions: The use of modulating backgrounds may increase the signal-to-noise ratio of flash ERGs and thus its diagnostic value. The dynamics of the response as a function of flash presentation time gives additional information about the retinal processing of flash and background. The photopic hill model allows the separation of processing in retinal On- and Off-pathways.
期刊介绍：
Documenta Ophthalmologica is an official publication of the International Society for Clinical Electrophysiology of Vision. The purpose of the journal is to promote the understanding and application of clinical electrophysiology of vision. Documenta Ophthalmologica will publish reviews, research articles, technical notes, brief reports and case studies which inform the readers about basic and clinical sciences related to visual electrodiagnosis and means to improve diagnosis and clinical management of patients using visual electrophysiology. Studies may involve animals or humans. In either case appropriate care must be taken to follow the Declaration of Helsinki for human subject or appropriate humane standards of animal care (e.g., the ARVO standards on Animal Care and Use).
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