Exposure to bright evening light linked to higher risk of age-related eye disease
Every sunrise and sunset sends the body a signal, keeping the circadian clock running on a roughly 24-hour cycle. This clock evolved so organisms could adapt to Earth’s daily rotation, syncing their biology to the pattern of day and night. Artificial lighting has freed human societies from relying on the sun to go about daily life, extending activity well into the night, but this convenience comes with a trade-off.
Researchers found that exposure to bright artificial light in the evening, especially between 8 p.m. and 11:30 p.m., may significantly increase the risk of developing serious eye diseases later in life. Those exposed to light levels above 1000 lux during these hours showed a notably higher likelihood of conditions such as age-related macular degeneration (AMD), cataracts and glaucoma.
It is not your living room lamp one needs to worry about, as standard indoor lighting, usually between 100 and 500 lux, stays safely within range. The real risk comes from extreme evening brightness from modern high-brightness screens and electronic displays, or occupational lighting in high-precision fields.
The findings are published in Gero Science.
Shedding light on eye disease risk
The eye does more than help us see. It also plays a key role in setting our internal body clock, and, as a result, the amount and timing of light exposure may influence how the eye ages over time. Age-related eye diseases (AREDs), such as macular degeneration, cataracts and glaucoma, are a group of conditions that commonly develop in older adults and can lead to significant vision loss.
Many of these conditions share biological processes, including long-term inflammation, oxidative stress and disruptions in cellular energy production.
Studies have shown that nighttime light exposure can affect conditions such as diabetes and heart disease, but its direct effects on the eye have not been explored in sufficient detail.
Researchers already knew there is a critical evening transition window when the body’s internal clock is especially sensitive to light. However, there was limited real-world data linking specific light levels during this period to the development of actual eye diseases.
In this study, the researchers followed a database of 82,826 participants from the UK Biobank. Anyone who already had eye diseases was excluded to specifically track new cases that developed over time.
Participants wore a wrist-worn device similar to a fitness tracker for seven continuous days. The high-resolution sensor in the wearable tracked movement and the amount of light (in units called lux) the person was exposed to every 1.2 seconds with high accuracy.
After the week of light monitoring, the researchers followed the participants’ health for an average of nearly eight years. The data pointed to a clear vulnerability threshold for eye health: average exposure to evening light exceeding 1,000 lux. In individuals consistently exposed to light above this level in the evening, the risk of developing major eye diseases rose sharply.
They observed a 31% higher risk of age-related macular degeneration, an 18% higher risk of cataracts and a 47% higher risk of primary open-angle glaucoma. The more time a person spent in bright light, the higher the risk.
Researchers suggest that this damage might be linked to disrupted circadian rhythms and exposure to blue light from modern LEDs, which can trigger oxidative stress and even cause photochemical damage in the delicate cells of the lens and retina.
Since high-intensity evening light is a modifiable risk factor, health care professionals can help people protect their long-term vision by choosing circadian-safe lighting, like dimming screens and using lower-intensity lights before bed.
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