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The Effect of Light Exposure and Refractive Error on Post-Illumination Pupil Responses

Beckett, David, Beckett
http://rave.ohiolink.edu/etdc/view?acc_num=osu152347133666468

Abstract Details

2018, Master of Science, Ohio State University, Vision Science.
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are preferentially sensitive to blue light, have input to the pupil response, integrate light exposure over long periods, synapse with dopaminergic amacrine cells, and may play a role the protective effect of time outdoors on myopia onset. Subjects with myopia may have different ipRGC response properties because time outdoors does not affect the rate of myopia progression. We evaluated the effect of light exposure on ipRGC-mediated pupil responses in subjects with myopia. Subjects were 10 myopic adults 24.6 ± 0.63 years of age (average ± SD), 60% female, with refractive errors ranging from -2.09 D to -4.78 D by cycloplegic autorefraction. Subjects were instructed to spend 5 days with a high level of outdoor activity and 5 days with a low level. Weeks were chosen in random order with at least 1 week of normal activity in between. Light exposure was monitored with an electronic personal light dosimeter (Daysimeter). The RAPDx pupilometer measured pupil responses to 6 cycles of either blue or red light stimuli oscillating at 0.1 Hz. The primary outcome was the average coefficient for the exponential decay function fit to the final 3 seconds of each redilation. Subjects experienced 0.5 log lux-minutes greater light exposure in their high light week compared to their low light week (p<0.0001). The average decay coefficient for the high week was -0.067 ± 0.038 and the low was -0.064 ± 0.052, which were not significantly different (p-value = 0.81). However, the effect of light exposure paradigms showed a significant interaction with refractive error (interaction p=0.044). Decay coefficients were more positive (slower redilation) for less myopic refractive errors in the low light week but more negative (faster redilation) for less myopic refractive errors in the high light week. We attribute slower redilation following blue-only stimulation to persistent input to the pupil response from ipRGCs. Higher light exposure appears to inhibit this potentially beneficial ipRGC activity in some myopes and may help explain why time outdoors lowers risk of onset but does not affect the rate of myopic progression.
Donald Mutti (Advisor)
Hartwick Andrew (Committee Member)
Walline Jeffrey (Committee Member)
71 p.
Ophthalmology; Optics
myopia, ipRGCs, PIPR, post-illumination pupil responses, dopamine

Recommended Citations

Citations

  • Beckett, Beckett, D. (2018). The Effect of Light Exposure and Refractive Error on Post-Illumination Pupil Responses [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu152347133666468

    APA Style (7th edition)

  • Beckett, Beckett, David. The Effect of Light Exposure and Refractive Error on Post-Illumination Pupil Responses . 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu152347133666468.

    MLA Style (8th edition)

  • Beckett, Beckett, David. "The Effect of Light Exposure and Refractive Error on Post-Illumination Pupil Responses ." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152347133666468

    Chicago Manual of Style (17th edition)

osu152347133666468
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This open access ETD is published by The Ohio State University and OhioLINK.