Research Publications
Key publications from the
Jeffery Light Lab
Research Publications
2026 / Scientific Reposrts
LED lighting (350-650nm) undermines human visual performance unless supplemented by wider spectra (400-1500nm+) like daylight
We show how specific lighting conditions affect brain responses and visual perception, using controlled experiments to link light exposure to changes in neural activity.
2025 / Scientific Reposrts
Longer wavelengths in sunlight pass through the human body and have a systemic impact which improves vision
This study shows that long‑wavelength red and infrared light from sunlight can pass through the human thorax and reach deep tissues. Brief 15‑minute exposures to 830–860 nm light over the chest improved visual function 24 hours later, even when no light reached the eyes. The effect is likely driven by enhanced mitochondrial function and ATP production, which can benefit distant organs such as the central nervous system. The findings suggest that everyday sunlight, even through clothing, may have therapeutic value by supporting mitochondrial health and counteracting age‑ and disease‑related decline.
2025 / Neural Regeneration Research
A spotlight on dosage and subject selection for effective neuroprotection: exploring the central role of mitochondria
Neurons are highly vulnerable cells, and many brain disorders involve mitochondrial dysfunction that drives their death, making effective neuroprotective treatments hard to achieve. This perspective argues that getting dose/application and subject selection right is crucial, using red to near‑infrared light therapy as an example, and proposes that targeting mitochondria in stressed neurons may offer a promising disease‑modifying strategy.
2023 / scientific reports
Watching the human retina breath in real time and the slowing of mitochondrial respiration with age
The retina has the greatest metabolic demand in the body particularly in dark adaptation when its sensitivity is enhanced. This requires elevated level of perfusion to sustain mitochondrial activity. However, mitochondrial performance declines with age, leading to reduced adaptive ability. We assessed human retina metabolism in vivo using broad band near-infrared spectroscopy (bNIRS), which records colour changes in mitochondria and blood as retinal metabolism shifts in response to changes in environmental luminance. We demonstrate a significant sustained rise in mitochondrial oxidative metabolism in the first 3 min of darkness in subjects under 50 years old. Rapid in vivo assessment of retinal metabolism with bNIRS provides a route to understanding fundamental physiology and early identification of retinal disease before pathology is established.
2024 / Journal of biophotonics
Light stimulation of mitochondria reduces blood glucose levels
Mitochondria regulate metabolism, but solar light influences its rate. Photobiomodulation (PBM) with red light (670 nm) increases mitochondrial membrane potentials and adenosine triphosphate production and may increase glucose demand. Here we show, with a glucose tolerance test, that PBM of normal subjects significantly reduces blood sugar levels. A 15 min exposure to 670 nm light reduced the degree of blood glucose elevation following glucose intake by 27.7%, integrated over 2 h after the glucose challenge. Maximum glucose spiking was reduced by 7.5%. Consequently, PBM with 670 nm light can be used to reduce blood glucose spikes following meals. This intervention may reduce damaging fluctuations of blood glucose on the body.
2022 / journal of biophotonics
Shifting patterns of cellular energy production (adenosine triphosphate) over the day and key timings for the effect of optical manipulation
Mitochondria are optically responsive organelles producing energy for cell function via adenosine triphosphate (ATP). But ATP production appears to vary over the day. Here we use Drosophila melanogaster to reveal daily shifts in whole animal ATP production in a tight 24 hours’ time series. We show a marked production peak in the morning that declines around midday and remains low through afternoon and night. In summary, long-wavelength influences on mitochondria are conserved across species from fly to human. Determining times for their administration to improve function in ageing and disease are of key importance. This study progresses this problem.
2021 / scientific reports
Weeklong improved colour contrasts sensitivity after single 670 nm exposures associated with enhanced mitochondrial function
Ageing reduces mitochondrial function, lowering ATP production and impairing cell performance. Studies suggest that exposure to long-wavelength light (650–900 nm) can improve mitochondrial efficiency, likely by reducing resistance around ATP-producing mechanisms.
This research shows that in humans aged 37–70, a single 3-minute exposure to 670 nm light can significantly improve cone-based colour vision for up to a week, bringing performance closer to younger levels. The effect depends on timing, and is especially relevant in modern environments where cone vision dominates due to artificial lighting.
2023 / aging cell
Use of 31P magnetisation transfer magnetic resonance spectroscopy to measure ATP changes after 670 nm transcranial photobiomodulation in older adults
Mitochondrial function declines with age and contributes to neurodegenerative disease, and photobiomodulation (long‑wavelength light therapy) has been suggested as a way to restore this function but remains clinically underused. This study shows that 670 nm photobiomodulation significantly increases ATP synthase flux in the brains of older adults, providing initial evidence that it can improve mitochondrial function with age, though larger studies are needed to confirm cognitive benefits.
2019 / scientific reports
A day in the life of mitochondria reveals shifting workloads
This study shows that mitochondrial function in Drosophila varies throughout the day. Activity of mitochondrial complexes and overall respiration peak in the afternoon, while ATP levels are over 40% higher in the morning and lowest at night, when glycolysis is highest.
These changes are driven by protein-level regulation rather than gene expression. The mismatch between peak ATP and peak complex activity suggests mitochondria are more efficient in the morning, leaving extra capacity later in the day.