The intrinsically photosensitive retinal ganglion cell (ipRGC) mediated pupil response in young adult humans with refractive errors.

Abstract

PURPOSE:

The intrinsically photosensitive retinal ganglion cells (ipRGCs) signal environmental light, with axons projected to the midbrain that control pupil size and circadian rhythms. Post-illumination pupil response (PIPR), a sustained pupil constriction after short-wavelength light stimulation, is an indirect measure of ipRGC activity. Here, we measured the PIPR in young adults with various refractive errors using a custom-made optical system.

METHODS:

PIPR was measured on myopic (-3.50 ± 1.82 D, n = 20) and non-myopic (+0.28 ± 0.23 D, n = 19) participants (mean age, 23.36 ± 3.06 years). The right eye was dilated and presented with long-wavelength (red, 625 nm, 3.68 × 1014 photons/cm2/s) and short-wavelength (blue, 470 nm, 3.24 × 1014 photons/cm2/s) 1 s and 5 s pulses of light, and the consensual response was measured in the left eye for 60 s following light offset. The 6 s and 30 s PIPR and early and late area under the curve (AUC) for 1 and 5 s stimuli were calculated.

RESULTS:

For most subjects, the 6 s and 30 s PIPR were significantly lower (p < 0.001), and the early and late AUC were significantly larger for 1 s blue light compared to red light (p < 0.001), suggesting a strong ipRGC response. The 5 s blue stimulation induced a slightly stronger melanopsin response, compared to 1 s stimulation with the same wavelength. However, none of the PIPR metrics were different between myopes and non-myopes for either stimulus duration (p > 0.05).

CONCLUSIONS:

We confirm previous research that there is no effect of refractive error on the PIPR.

• Authors: Ranjay Chakraborty, Michael J Collins, Henry Kricancic, Daniel Moderiano, Brett Davis, David Alonso-Caneiro, Fan Yi, Karthikeyan Baskaran
• Journal: Journal of optometry (J Optom) 2022 Apr-Jun Vol. 15 Issue 2 Pg. 112-121 ISSN: 1989-1342 [Electronic] Spain
• PMID: 33402286 (Publication Type: Journal Article)
• Copyright: Copyright © 2020 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

Topics

• Adult
• Circadian Rhythm
• Humans
• Myopia
• Photic Stimulation
• Pupil (physiology)
• Refractive Errors
• Retinal Ganglion Cells
• Young Adult