New Study Shows Sunlight’s Infrared Light Passes Straight Through Your Chest and Improves Vision

A fresh study published in Scientific Reports, delivers a straightforward message: longer wavelengths in regular sunlight pass right through the human body and improve vision the next day. The effect shows up even when the light never reaches the eyes.

Researchers measured sunlight traveling through the chests of volunteers. Infrared wavelengths around 830 to 860 nanometers made it through. Clothing cut the intensity but did not stop the light. They then used controlled 850 nanometer LED panels in the lab, shining the light on people’s backs for 15 minutes. Some participants had their heads wrapped in foil so no light could reach the eyes. Color contrast tests the next day showed clear gains, about 16% better on the blue-yellow scale and 9% on the red-green scale when the whole back was exposed. Even the foil-wrapped group improved by roughly 7% on the more sensitive test. Controls who got no light showed no change.

The mechanism tracks with earlier work on mitochondria, the tiny power plants inside cells. Longer red and near-infrared light raises their membrane potential and ATP output, especially as function declines with age. The outer retina packs more mitochondria than almost any other tissue, so vision responds quickly. Benefits from light on one body area can spread system-wide, possibly through signaling molecules in the blood. Animal studies had pointed this way; this work confirms it in people.

This matters because modern life keeps many indoors under lighting heavy on shorter wavelengths and short on the longer ones found in natural sunlight. The body evolved under the full solar spectrum. Blocking most of that spectrum while sitting under artificial lights and screens may leave cellular energy production weaker than it needs to be. The study notes that sunlight’s longer wavelengths can reach key organs even through clothing and help counter the mitochondrial slowdown that comes with age and disease.

Practical takeaway is simple. Time outdoors in daylight gives the body access to wavelengths it uses for more than vitamin D. Fifteen minutes of targeted longer-wavelength exposure produced measurable vision gains a day later. No expensive gadget or app required, just ordinary sunlight doing what it has done for ages.

Big tech companies sell endless indoor devices and filtered digital environments. This research suggests the older, freer alternative still works better for basic human function. Getting outside remains one of the cheapest, least controlled ways to support the systems that keep sight sharp.

Sources / More reading

Original study: Longer wavelengths in sunlight pass through the human body and have a systemic impact which improves vision. Scientific Reports (2025). https://www.nature.com/articles/s41598-025-09785-3

PubMed abstract: https://pubmed.ncbi.nlm.nih.gov/40628952/

Full text via PMC: https://pmc.ncbi.nlm.nih.gov/articles/PMC12238558/

Related coverage and discussion: https://www.connealymd.com/how-does-sunlight-improve-eyesight/

See Dr. Roger Seheult, MD, on Twitter/X: https://x.com/RogerSeheult

Additional analysis: https://todayspractitioner.com/eye-health/sunlight-as-a-non-invasive-modulator-of-ocular-and-systemic-mitochondrial-function/