Neglecting your sleep could be ruining your eyes

Turns out those long nights you spent up past your bedtime as a young adult may have had a major impact on the way your eyes developed.

Researchers at Flinders University in Adelaide, Australia, found that people who are myopic, or shortsighted, are more likely to have delayed circadian rhythms than people who are not. 

Our circadian rhythms are our internal clocks that regulate our sleep-wake cycles and other bodily functions, including in the eye.

“Just like the circadian rhythms of the body, like our sleep-wake cycle, we also have rhythms within the eye,” said researcher  Ranjay Chakraborty.  “[T]he integrity of those rhythms are essential for normal growth of the eye.”

So how does bad sleep lead to shortsightedness? It’s likely part of a chain of events that happens prior to the development of myopia — due in part to our ever-present screens.

“It starts with light exposure,” Chakraborty said. “This potentially causes a delay in our circadian rhythms and the reduced production of melatonin. And this can then affect important rhythms within the eye that could then predispose people to myopia.”

The light exposure he’s talking about? The blue light emitted from our devices, which can interrupt the release of melatonin, making it harder for us to fall asleep.

“One of the parameters we looked at [for our study] was the amount of light [subjects] were exposed to before they went to bed. It looks like people with shortsightedness had significantly more light exposure in general at least one hour and three hours before bed,” he said. 

How you become shortsighted

In people with normal vision, images focus directly on the retina. However, myopic eyes are slightly elongated compared to the eyes of people with normal vision, so the image focuses in front of the retina, which makes images appear blurry. 

“Even though it’s the most prevalent vision disorder in the world, we don’t know a lot about what causes it,” says Dr. Chakraborty.

What we do know is that there are two common themes that underlie the disorder. The first is what researchers refer to as “near-work” or activities that you perform at a short distance. That includes looking at your phone, reading books or working on a computer — all of which change the way your eye grows. The more time you spend focusing on objects up close, the more your eyes develop to accommodate that.

Another big underlying risk factor is how much time you spend indoors. Spending time outdoors makes your body release more of the neurotransmitter dopamine, which helps protect against myopia.

Is there a cure for myopia?

Unfortunately, if you’ve already got myopia, you’re stuck with it. Myopia tends to develop during puberty and peaks in adulthood. Short of laser-eye surgery, the only option is corrective lenses. 

But scientists are hopeful that, with studies like Chakraborty’s, we may be able to prevent it before it sets in.