Glaucoma is one of the leading causes of permanent blindness in the world. It damages the optic nerve, often without warning, and once the damage is done, it cannot be reversed. More than 70 million people are affected worldwide.
One of the main causes of this damage is high internal eye pressure, also called intraocular pressure or IOP. A new study suggests that something as simple as sleeping without pillows could help lower this pressure.
The study was done by researchers from China and was published in the British Journal of Ophthalmology. They found that sleeping with two regular pillows may raise internal eye pressure during sleep, especially in people who already have glaucoma.
The scientists wanted to understand how pillow use might change eye pressure and whether it could affect the fluid that drains from the eye.
When you sleep on your back, your head and neck position matter. Stacking pillows raises your head and bends your neck, which may press on a large vein in your neck called the jugular vein.
This can interfere with the drainage of a fluid in your eye called aqueous humor. This fluid keeps the eye healthy and helps it keep its shape. But if it doesn’t drain properly, pressure builds up, which may harm the optic nerve.
To find out how much pillows affect IOP, researchers studied 144 adults with different types of glaucoma. Some had normal tension glaucoma, others had high pressure glaucoma, and many had primary open angle glaucoma, which is the most common kind.
These people were divided into three age groups, and each person had their right eye’s pressure measured every two hours over a full day and night.
Participants were asked to sleep both with and without pillows. When they used two pillows, their heads were lifted about 20 to 35 degrees. The results showed that about two-thirds of the participants had higher eye pressure when sleeping with pillows.
The average increase was around 1.6 mm Hg. Although this might sound small, it can be important for people already at risk.
Not only did eye pressure increase, but another measure called ocular perfusion pressure (OPP) decreased. OPP shows how much blood flow reaches the eye. Less blood flow can mean less oxygen and nutrients for eye tissues.
This is especially concerning because low OPP has been linked to worsening glaucoma. The study found that young adults and people with open angle glaucoma had the biggest changes in pressure when using pillows.
The researchers also tested blood flow in the neck veins of healthy volunteers. They found that pillows made the vein narrower and increased the speed of the blood flow, possibly showing signs of pressure.
The researchers explained that current treatments for glaucoma mostly rely on medications or laser therapy to lower eye pressure, especially at night. But this new study suggests that changing sleeping posture could also help.
They believe that avoiding sleeping positions that bend the neck or compress the neck veins might be a useful and simple way to help control eye pressure.
This was an observational study, which means it cannot prove cause and effect. It also had a few limitations, like small groups of people for each type of glaucoma. Still, the results point to a possible new strategy to help people with glaucoma protect their vision: try sleeping with fewer pillows or with your head in a more natural position.
More studies are needed, but this simple idea—changing how you sleep—might one day become part of how doctors help people keep their eyes healthy.
If you care about eye health, please read studies about how vitamin B may help fight vision loss, and MIND diet may reduce risk of vision loss disease.
For more information about eye disease, please see recent studies about how to protect your eyes from glaucoma, and results showing this eye surgery may reduce dementia risk.
The study is published in the British Journal of Ophthalmology.
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