India, Jan. 29 -- London (PAMedia/dpa) - Sleeping without a pillow may be better for people with a common eye condition, a study suggests. Stacking two pillows in bed was linked to higher pressure inside the eye among glaucoma patients. This may be down to pressure on the jugular vein, the main blood vessels in the neck, researchers in China said. The study, published in the British Journal of Ophthalmology, included 144 people with glaucoma. The condition is usually caused when fluid builds up in the front part of the eye, damaging the optic nerve, which connects the eye and the brain. It is most common in people over 50 and while it does not usually have symptoms, it can cause blindness if left untreated. Researchers measured internal pre...