Sleeping without a pillow may reduce nighttime eye pressure in glaucoma - study

Sleeping without a pillow may help reduce potentially harmful intraocular pressure (IOP) in people with glaucoma, according to preliminary data published online in the British Journal of Ophthalmology.

The researchers explain the possible mechanism as follows: when a person sleeps on two pillows, the position of the neck changes, which can compress the jugular vein and interfere with the natural outflow of intraocular fluid (aqueous humour). And it is the buildup of pressure in the eye over time that can damage the optic nerve.

How the study was conducted

The authors analysed data from 144 adults with glaucoma and assessed how IOP changes with different body positions. Participants had their IOP measured every two hours throughout the day (sitting and lying down). Then, in the supine position, the head was raised 20-35° with two standard pillows and the pressure was measured again after 10 minutes.

Results

In general, when using two pillows, IOP was higher than in the supine position without head elevation (average 17.42 mmHg vs. 16.62 mmHg), and pressure fluctuations over 24 hours became more pronounced.

At the same time, ophthalmoperfusion pressure (OPP), a measure related to how efficiently blood is "pushed" through the small vessels of the eye, also decreased: it was lower with two pillows (approximately 54.57 mmHg versus 58.71 mmHg in the no-lift position).

Separately, the researchers also examined blood flow in the jugular vein region of a small group of healthy volunteers and reported that with cushioning, the vein lumen became more "narrowed" and blood flow velocity increased - consistent with the hypothesis of vein compression due to neck flexion.

What this means in practice

The authors emphasise: the work is observational, so it does not prove causation and requires confirmation in further studies. However, they suggest that 'positional' changes should be considered as a potentially simple complementary approach to controlling nocturnal IOP - alongside medication and procedures.

Important: if a person has been diagnosed with glaucoma, any changes to sleep habits are best discussed with an ophthalmologist (e.g. if there are neck/back problems or other contraindications).