A missing color in indoor light may help prevent myopia

Indoor lighting may play a role in preventing myopia, a condition that affects nearsightedness in children who spend more time indoors and less time outdoors. A recent study published in Cell Reports Medicine reveals that exposure to indigo light, a short wavelength of visible light abundant in natural sunlight but lacking in standard white LED lighting, can effectively prevent the development of myopia in tree shrews.

Tree shrews were chosen for the experiments due to their eyes' anatomical and optical similarities to human eyes. The researchers used tiny spectacles to produce a strong signal that encouraged myopia in one eye, while the other eye served as a comparison. The study measured eye shape and axial length using a biometer and monitored changes in refraction using an autorefractor.

Although violet light near 380 nanometers had shown a protective effect in previous mouse studies, it did not produce the same response in tree shrews, leading researchers to explore slightly longer wavelengths. Indigo light ranging from 419 to 446 nanometers emerged as the most effective at preventing myopia. This wavelength passes through the lens and activates a biological pathway involved in nonvisual opsins, which are essential for biological processes beyond forming images.

The findings suggest that modern indoor environments may expose developing eyes to a different spectrum of light than humans experienced throughout most of their evolution, increasing the risk of myopia. While spending more time outdoors is a possible strategy for reducing myopia, redesigning indoor lighting to better replicate the wavelengths present outdoors is another promising approach.

Enhanced lighting systems in daycare spaces are being considered in the next stage of the research to determine if indigo-enriched lighting can indeed prevent myopia in children.