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Lydia Pickrell Thesis 2020 .pdf (689.58 KB)

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The Effect of Dark Adaptation on Red and Blue Light-Driven Pupil Responses

Pickrell, Lydia Mary
http://rave.ohiolink.edu/etdc/view?acc_num=osu1586380901812279

Abstract Details

2020, Master of Science, Ohio State University, Vision Science.
Purpose: Time spent outdoors has been consistently associated with delaying the onset of myopia. This association may be due to the involvement of intrinsically photosensitive retinal ganglion cells (ipRGCs), considering their role in long-term ambient illumination detection and connection with dopaminergic amacrine cells. Pupil responses driven by ipRGC input have typically been measured clinically in response to flashes of red and blue light following dark adaptation. However, this is not a feasible method for testing children, as dark adaptation adds a significant amount of time to each trial. The purpose of this study was to evaluate the effect of dark adaptation on the pupil responses to red and blue light stimulation. Methods: Subjects were 20 adults age 24.0 ± 2.37 years (average ± SD), 55% female, with an average spherical equivalent (SEQ) refractive error of -3.22 ± 2.78 diopters (Grand Seiko WR-5100K cycloplegic autorefraction), ranging from -10.61 to +0.77 diopters. The RAPDx pupilometer measured pupil sizes in response to blue and/or red light oscillating at a low temporal frequency of 0.1Hz. The standard testing protocol included 5 minutes of dark adaptation prior to each of three stimulus conditions: alternating red and blue, red-only, then blue-only. Subjects repeated this standard protocol without dark adaptation. This study also evaluated whether pupil responses might be enhanced by two minutes of red-only stimulation (instead of the standard one minute), once with and once without dark adaptation. These 4 test conditions were conducted in random order on separate days. The primary outcome measure was the difference in normalized pupil size in response to blue-only light compared to blue during the alternating condition. Results: Consistent with previous research, pupils tended to become more constricted with repeated exposure to blue light. The average difference (±SD) in normalized pupil size between blue-only and alternating blue conditions with dark adaptation was 10 ± 2.4%. Without dark adaptation, the pupil did not become as constricted with repeated exposure to blue light, with the difference reduced by 2.8% (repeated measures ANOVA; p<0.0001). Compared to the standard protocol, the longer exposure to red light had no significant effect on the pupil responses to repeated pulses of blue light (0.8% difference, p = 0.18). Conclusion: Dark adaptation resulted in a significant reduction in pupil size in response to repeated pulses of blue light compared to the identical protocols without dark adaptation. Increasing the exposure to red light had no effect on pupil size in response to repeated pulses of blue light. Use of dark adaptation needs to be taken into account during pupillary testing. This effect could be attributed to an increase in the amount of time between light exposures allowing dopamine to diffuse throughout the retina and decrease the threshold levels of the retinal cells driving the pupil response.
Donald Mutti (Advisor)
65 p.
Optics
pupil responses; myopia; ipRGCs; dark adaptation

Recommended Citations

Citations

  • Pickrell, L. M. (2020). The Effect of Dark Adaptation on Red and Blue Light-Driven Pupil Responses [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586380901812279

    APA Style (7th edition)

  • Pickrell, Lydia. The Effect of Dark Adaptation on Red and Blue Light-Driven Pupil Responses. 2020. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1586380901812279.

    MLA Style (8th edition)

  • Pickrell, Lydia. "The Effect of Dark Adaptation on Red and Blue Light-Driven Pupil Responses." Master's thesis, Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586380901812279

    Chicago Manual of Style (17th edition)

osu1586380901812279
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