Swimming, weight training, yoga and playing wind instruments can cause spikes in intraocular pressure (IOP), which may pose a risk for IOP-related conditions such as glaucoma, keratectasia and axial myopia, according to a literature review in the October issue of Optometry and Vision Science.

Simple actions, such as repeatedly taking deep breaths, can cause marked variations in IOP; however, certain activities, such as forcibly exerting effort while holding your breath (Valsalva maneuver) or remaining in an inverted yoga position for 20 minutes or longer, can cause volatile IOP spikes, says author Charles W. McMonnies, M.Sc., Ph.D. He noted that extreme Valsalva maneuvers, such as playing high wind-resistant instruments (trumpets, oboes, French horns or bassoons), could temporarily cause an individuals IOP to increase by as much as 210%.

The worst culprit: Chronic, bilateral knuckle eye rubbing could increase an individuals IOP up to 10 times the normal level, Dr. McMonnies noted. He recommends that people should avoid sleeping facedown on a pillow because of inadvertent nocturnal eye rubbing.

All patients should participate in a self-administered intraocular pressure survey to determine if they are at particular risk for IOP spikes and/or IOP-related eye diseases, Dr. McMonnies concluded. Recommended survey questions include:

How often do you rub your eyes?

How often do you do yoga?

Do you play wind instruments?

In what position do you normally sleep?

Any action that produces a Valsalva maneuver will cause an immediate rise in IOP, says Pinakin Gunvant, B.S.Optom., Ph.D., of Memphis, Tenn, commenting on the findings. This is in part because of the engorgement of choroidal vessels, which leads to an increase in ocular volume. However, the scleral coat does not stretch proportionately to accommodate this change, thus leading to an increase in IOP.

Also, a change in body position from erect to supine can lead to an increase in IOP of up to 16mm Hg. Complete inversion of body position from erect to upside down can lead to doubling of normal IOP, Dr. Gunvant says. Nevertheless, the negative long term ocular effects of such activities are still widely unknown.

McMonnies CW. Intraocular pressure spikes in keratectasia, axial myopia, and glaucoma. Optom Vis Sci 2008 Oct;85(10):1018-26.

Vol. No: 145:11Issue: 11/15/2008