Electrochromic selective filtering of chronodisruptive visible wavelengths

PLoS One. 2020 Nov 5;15(11):e0241900. doi: 10.1371/journal.pone.0241900. eCollection 2020.

Abstract

We present evidence of pupil response modification, as well as differential theoretical melatonin suppression through selective and dynamic electrochromic filtering of visible light in the 400-500 nm range to minimize chronodisruptive nocturnal blue light exposure. A lower activation of intrinsically photosensitive retinal ganglion cells (ipRGCs), the first step for light to reach a human's internal clock, is related to melatonin secretion therefore avoiding detrimental effects of excessive blue light exposure. Pupillary Light Reflex and Color Naming were experimentally assessed under light filtered by two different coloration states (transmissive and absorptive) of these novel dynamic filters, plus an uncoated test device, in 16 volunteers. Also, different commercial light sources at illuminances ranging from 1 to 1000 lux were differentially filtered and compared in terms of theoretical melatonin suppression. Representative parameters of the pupil responses reflected lower pupil constriction when the electrochromic filters (ECFs) were switched on (absorptive state, blue light is absorbed by the filter) compared to uncoated filters (control sample), but failed to do so under transmissive state (blue light passes through the filter) indicating less activation of ipRGCs under absorptive state (although no significant differences between states was found). Out of eight colors tested, just one showed significant differences in naming between both filter states. Thus, the ECF would have some protecting effect on ipRGC activation with very limited changes in color perception. While there are some limitations of the theoretical model used, the absorptive state yielded significantly lower theoretical melatonin suppression in all those light sources containing blue wavelengths across the illuminance range tested. This would open the way for further research on biological applications of electrochromic devices.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Color
  • Female
  • Humans
  • Light
  • Male
  • Melatonin / metabolism
  • Middle Aged
  • Photic Stimulation / methods
  • Pupil / physiology*
  • Reflex, Pupillary / physiology*
  • Retinal Ganglion Cells / physiology*

Substances

  • Melatonin

Grants and funding

This work was supported by the Ministry of Economy and Competitiveness, the Instituto de Salud Carlos III through a CIBERFES grant (CB16/10/00239) awarded to JAM, the Fundación Séneca through grant 19899/GERM/15 awarded to JAM, and the Ministry of Science, Innovation and Universities through grant RTI2018-093528-B-I00 awarded to MAR and Call H2020-sc1-BHC- 2018-2020 (Grant agreement 825546, Diabrail-Latam) awarded to MAR (all of them co-financed by FEDER). Research fellowship granted to MAB-C (20401/SF/17) by the Fundación Séneca and to RA-P (FPU13/01421) by Ministry of Education, Culture and Sports. JP acknowledges funding from Fundación Séneca (grants 20529/PDC/18 and 20985/PI/18) and Ministry of Economy and Competitiveness through grant ENE2016-79282-C5-5- R. AMÖ and JRR gratefully acknowledge the financial support from the Air Force Office of Scientific Research (FA9550-18-1-0184).