LED lighting undermines visual performance unless supplemented by wider spectra

Original Article ↗ Hacker News Discussion ↗

Scope of the paper vs popular interpretations

  • Several commenters note the paper is about near‑infrared (NIR) and mitochondrial effects, not visible color rendering or CRI.
  • Others conflate it with common complaints about LED color quality; a few point out that color/fidelity issues can’t explain the studied effect because the control conditions partially rule out pure metamerism.
  • Some see the claim that brief 670 nm exposure improves vision for days as “extraordinary” and demand replication and a clear mechanism.

Color spectrum, CRI, and subjective experience

  • Many report LEDs feeling “bright but not illuminating,” especially in streetlights, car lamps, and cheap bulbs; sodium/mercury and incandescent are described as more comfortable or “natural.”
  • Discussion of CRI/Rf, R9, and SSI:
    • Cheap “blue LED + phosphor” bulbs have gaps in the spectrum, especially in reds and sometimes cyan, causing poor color rendering and orientation issues.
    • High‑CRI and “full‑spectrum” LEDs exist (sometimes 95–99 CRI), but are expensive, rare in bulb form, and often still lack NIR.
    • Some argue 90 CRI is not enough; others find high‑CRI LEDs still inferior to halogen/incandescent for reading comfort.

Infrared, “full spectrum” lighting, and alternatives

  • Commenters note LEDs can be engineered with smoother spectra and NIR/UV, but such products are niche (movie/theater lights, therapy panels, a few costly bulbs).
  • One thread describes experimental “modern incandescent” concepts using spectral filters to keep IR inside and emit mostly visible light, potentially trading some efficiency for beneficial NIR.
  • Debate over whether IR is a “feature” (possible biological benefits) or an energy‑wasting “bug.”

Health, regulation, and energy trade‑offs

  • Strong disagreement over whether LED spectrum/flicker meaningfully harms health (eyestrain vs cancer/metabolic effects). Evidence is called “mostly unsubstantiated” by some and “ignored like asbestos” by others.
  • Policy dimension: bans on incandescent and fluorescent lamps in EU/Australia/US are seen by some as premature or “captured,” by others as justified by large CO₂ and grid‑stability benefits.
  • Practical question raised: even if spectrum is better, is higher operating cost per bulb worth it at typical electricity prices?

Methodological and journal skepticism

  • Critics highlight small sample size, baseline performance differences between groups, unblinded visible changes (warmer/brighter task lamps), and lack of strong controls (e.g., IR‑only vs heat‑only).
  • “Scientific Reports” is labeled a weak venue; commenters call for replication, preregistration, better controls, and high‑end LED comparisons before drawing broad conclusions.

Flicker and practical experiences

  • Several describe perceiving flicker (often at 50/60 Hz or from drivers) and associated headaches or “fatigue,” especially with cheap bulbs.
  • Discussion of DC drivers and better electronics: good LEDs can be effectively flicker‑free, but many consumer products are not.
  • Some users revert to incandescent/halogen for evening or reading while retaining LEDs for high‑power/general use.