Nocturnal IOP lower with elevated head

When people sleep with their heads elevated 20 degrees, their nocturnal IOP is lower than when they sleep with their heads flat, finds a study newly published in the Journal of Glaucoma..

Thirty patients - 15 who said they had glaucoma and 15 who said they did not - participated in the prospective, non-randomized comparative case series. Each of them slept in a sleep laboratory on 2 different nights, 1 night lying in a supine position and the other lying on a wedge-shaped pillow at a 20-degree head-up position. The researchers measured baseline IOP at 10 pm while participants were awake and then measured IOP every 2 hours while participants slept, at midnight, 2 am, 4 am and 6 am.

Position did not significantly affect IOP as measured when participants were awake. When participants were sleeping, however, mean IOP was 1.51 mmHg higher when participants were in the supine position than when they were in the head-up position, with an average increase of 1.56 mmHg in those with glaucoma and 1.47 mmHg in those without the disease. In fact, 25 of the 30 patients had lower mean IOP when they were in the 20-degree head-up position than when lying flat. For 11 of them, mean IOP reduction was more than 10%.

To read an abstract of the study or download the full article, go to the journal's website.