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Full text release has been delayed at the author's request until December 16, 2024

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Effect of Peripheral Defocus on Retinal Function via Mathematical Modeling of the Multifocal Electroretinogram Response

Knapp, Jonelle
http://orcid.org/0000-0001-6641-6824
http://rave.ohiolink.edu/etdc/view?acc_num=osu1574626289219112

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Vision Science.
The multifocal electroretinogram (mfERG) provides an objective electrophysiological assessment of central retinal function. Using this technique, many focal retinal responses are recorded from the cone-driven retina in a matter of minutes. MfERG metrics can be used to identify focal areas of retinal dysfunction (a delay in the timing of the mfERG response, a decrease in its amplitude, or both indicate abnormal retinal function) even when there are no visible signs of retinopathy. The mfERG is an objective test of retinal function, but the timing and amplitude of the response are measured subjectively by manually marking the location of key points within the mfERG waveform. As a result, mfERG metrics may differ between graders, especially when the waveform is irregular (e.g., in cases of active eye disease or when the response is contaminated with electrical interference). Differences in mfERG measurements due to variability between graders may be a concern in longitudinal or multicenter research studies when more than one person is tasked with measuring the mfERG response. Mathematical modeling of the mfERG waveform might be an objective method to reliably and efficiently measure mfERG metrics and mitigate the effects of inter-rater variability. One aim of this research was to model the mfERG waveform using a custom Fourier curve fitting algorithm and automatically extract mfERG timing and amplitude measures. Data presented here show that custom curve fitting using a Fourier model accurately and objectively identified and measured the peak time and amplitude of key mfERG waveform parameters. The second aim of this research was to utilize the model to efficiently and reliably measure mfERG response parameters at different retinal eccentricities. These measurements were used to investigate the relationship between peripheral axial length and retinal function (i.e., mfERG peak time and amplitude). We found that axial length was not a significant predictor of mfERG peak time nor amplitude in our study population. This was an unexpected finding as other researchers have reported that mfERG peak times were delayed and amplitudes were decreased in eyes with myopia. Subjects tested in comparable studies had higher levels of myopia (and longer axial lengths) than those tested in our study population. It is probable that the subjects in other studies (with higher levels of myopia) had early, undetectable myopia-related pathology that caused retinal dysfunction whereas our subjects (with lower levels of myopia) did not. Lastly, changes in peripheral retinal function in response to systematic changes in peripheral myopic defocus were investigated. Multifocal contact lenses that induce peripheral defocus as a stimulus to slow eye growth are a popular treatment to control myopia progression. However, peripheral myopic defocus may have unforeseen consequences, especially in younger patients who are currently being prescribed multifocal contact lenses for myopia control. Here, we found that induced peripheral myopic defocus decreased the amplitude of the mfERG response. This finding suggests peripheral blur may potentially cause photoreceptor or bipolar cell (or both) dysfunction. The mfERG may offer an objective method to quantify the short-term and long-term effects of peripheral myopic defocus on retinal function.
Dean VanNasdale, OD, MS, PhD (Advisor)
260 p.
Biomedical Research
axial length; inter-rater variability; intra-rater variability; multifocal electroretinogram; myopia; myopia control; myopic defocus; peripheral defocus; retinal function

Recommended Citations

Citations

  • Knapp, J. (2019). Effect of Peripheral Defocus on Retinal Function via Mathematical Modeling of the Multifocal Electroretinogram Response [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574626289219112

    APA Style (7th edition)

  • Knapp, Jonelle. Effect of Peripheral Defocus on Retinal Function via Mathematical Modeling of the Multifocal Electroretinogram Response . 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1574626289219112.

    MLA Style (8th edition)

  • Knapp, Jonelle. "Effect of Peripheral Defocus on Retinal Function via Mathematical Modeling of the Multifocal Electroretinogram Response ." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574626289219112

    Chicago Manual of Style (17th edition)

osu1574626289219112
© 2019, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.