Does more outdoor light at night help cause macular degeneration? (Association suggests it is possible)

Medical Xpress / JAMA Network Open ^ | Sept. 17, 2024 | Ernie Mundell / Su Hwan Kim et al

[ConservativeMind]

As levels of nighttime artificial outdoor light rise, so do the odds for a leading cause of vision loss, age-related macular degeneration (AMD).

Researchers found that people living in areas of that country with the highest levels of streetlights and other artificial light had more than double the odds for AMD, compared to those living in areas with the lowest levels.

That risk remained even after they accounted for confounding factors such as sleep issues and depression, said a team led by Dr. Ahnul Ha.

City dwellers may be at particular danger for macular degeneration, since the link between the illness and artificial outdoor light "was found solely in urban areas, where the mean outdoor-artificial-light-at-night level was three times higher than in rural areas," Ha's group reported.

AMD occurs when a part of the eye's retina called the macula deteriorates over time. People begin to lose their central vision, making common tasks such as driving or reading difficult.

There's research suggesting that artificial light might harm the retina in various ways. Light exposure can damage sensitive retinal cells, Ha's group noted. It can also upset circadian rhythms and damage these cells, and it can trigger hormonal changes that might also be harmful.

In the new research, Ha and her colleagues analyzed data on over 126,000 South Koreans ages 50 or older. About 4,100 of them had been diagnosed with AMD.

The main finding: Older people who lived in urban areas with the highest levels of outdoor artificial light had 2.17 times the odds of developing AMD, compared to folks living in areas with the lowest levels.

Living in an area that had even just a bit more nighttime artificial light (compared to areas with the lowest levels) was still linked to a 12% higher risk for AMD.

[DollyCali]

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