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

• Ranjay Chakraborty ^{[1] [1]} ; Michael J. Collins ^[2] ; Henry Kricancic ^[2] ; Daniel Moderiano ^[1] ; Brett Davis ^[2] ; David Alonso-Caneiro ^[2] ; Fan Yi ^[2] ; Karthikeyan Baskaran ^[3]
  1. [1] Flinders University

     Flinders University

     Australia

     
  2. [2] Queensland University of Technology

     Queensland University of Technology

     Australia

     
  3. [3] Linnaeus University

     Linnaeus University

     Suecia

     

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• Localización: Journal of Optometry: peer-reviewed Journal of the Spanish General Council of Optometry, ISSN-e 1888-4296, Vol. 15, Nº. 2, 2022, págs. 112-121
• Idioma: inglés
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  • 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.