Children who spend more time indoors and less time outside are more likely to develop myopia, or nearsightedness. The problem is growing fast. Some experts estimate that nearly 5 billion people, about half the world, could be nearsighted by 2050.
A study led by scientists at Cincinnati Children's and the University of Alabama at Birmingham points to indoor lighting as one possible way to lower that risk. The work appeared online on Aug. 18, 2026, in Cell Reports Medicine.
The team looked at indigo light, a short wavelength that is plentiful in sunlight but largely missing from standard white LED bulbs. In tests with tree shrews, whose visual systems share important similarities with humans, indigo light completely prevented nearsightedness.
"The model of myopia we use in the tree shrew is fairly extreme," says Richard Lang, who leads ophthalmology research at Cincinnati Children's. "So, if indigo light can suppress myopia in these tests, then it should also be quite effective in humans."
Standard white LEDs generally peak around 450 nanometers and give plenty of longer-wavelength light for ordinary vision. They contain relatively little indigo light, which appears to switch on light-sensitive proteins involved in processes beyond forming images.
"We evolved outside in the full-spectrum light provided by our sun," Lang says. "When we live inside, we don't get all the wavelengths the eye needs for normal refractive development, and so we get myopia. That's the basic message of this paper."
One answer is more time outdoors, where eyes shift focus between near and far objects and receive the full mix of sunlight. The researchers note that it may be hard to reverse indoor, technology-centered life on a large scale. Another option is to redesign indoor lighting so it better matches outdoor wavelengths.
The next step is not simply to make rooms brighter. Researchers want indoor light to be more biologically complete. They plan to install improved lighting in participating daycare centers and follow children over time, comparing myopia rates with centers that use ordinary lights.
Tree shrew results were strong, but it is still unknown whether indigo-enriched lighting can prevent myopia in children. "If future clinical studies confirm the findings," Lang says, "indigo-enriched lighting could become a safe, passive and scalable way to help reduce childhood myopia risk."