May 2008

 

OPHTHALMOLOGY NEWS

 

Heading toward an IOP rise


by Vanessa Caceres EyeWorld Contributing Editor

 

 

Glaucoma patients should avoid this common yoga posture

Advise your glaucoma patients not to stand on their head when exercising. It seems like a simple albeit uncommon piece of advice. Still, it’s something more ophthalmologists might say as the number of Americans who want to try yoga increases.

Yoga Journal reported in February that Americans spend $5.7 billion a year on yoga equipment, clothing, vacations, DVDs, and books. That’s an 87% increase compared with the journal’s study in 2004. The study also found that 6.9% of American adults practice yoga—or 15.8 million people. Of course, the number of patients who practice yoga in other areas of the world is even higher. The Yoga Journal study reported more Americans turning to yoga as medical therapy.

A common postural position in yoga is the Sirsasana, in which practitioners stand on their head for a period of time.

However, some recent reports have tracked IOP increases that nearly double during the headstand position compared with when in a sitting position.

Here’s a look at what some recent reports in this area have found.

Headstands and IOP

A study published in 2006 in Ophthalmology from Mani Baskaran, D.O., D.N.B., consultant, Glaucoma Services, Medical and Vision Research Foundation, Chennai, India, measured IOP in 75 subjects from a yoga training institute. They measured IOP with a Tono-Pen (Medtronic Solan, Jacksonville, Fla.) before, during, and after the Sirsasana position. None of the subjects had glaucoma.

The mean baseline sitting IOP was 14.24 mm Hg; IOP increased two-fold in all subjects during the Sirsasana position. However, the IOP returned to near baseline level just as soon as patients were sitting again. Investigators did not find any significant correlations between subjects’ age, duration of Sirsasana, corneal curvature, central corneal thickness, and vertical cup-to-disc ratio. In a report from the British Journal of Ophthalmology in 2007, Dimiter Robert Bertschinger, M.D., University Eye Clinic, Geneva, Switzerland, and co-authors, presented a 46-year-old woman with previous juvenile open-angle glaucoma who had worsening glaucomatous visual field defects in both eyes one year after starting to perform the Sirsasana position. Her IOP had been stable (between 14 and 16 mm Hg) for 20 years, as she had previously had a bilateral trabeculectomy.

“Slitlamp examination revealed no apparent reason for the visual field deterioration,” the investigators wrote. “Detailed history taking finally showed that she had started one year previously [to] regularly practice yoga,” particularly the headstand position. Her IOP was measured to increase from 16 mm Hg in a sitting position to 32 mm Hg when she was in the headstand position.

“We asked the patient to stop any yoga exercise with the head-down position, and some months later the visual field defects improved significantly,” the investigators wrote.

Dr. Bertschinger and co-investigators also compared IOP differences in 10 healthy volunteers who did not normally practice yoga. They also found a two-fold increase in IOP during Sirsasana, from a mean of 13.9 mm Hg while sitting to 31.8 mm Hg during the headstand posture.

“Increased IOP has been explained with raised episcleral venous pressure or increased choroidal volume by vascular engorgement,” they wrote.

In a third report, published in 2006 in Advances in Therapy, Mark J. Gallardo, M.D., Department of Ophthalmology, University of Texas, Dallas, and co-investigators presented a 46-year-old woman with progressive glaucomatous optic neuropathy and visual field loss. They discovered that she had practiced the Sirsasana posture for a half hour daily for 10 years and that her IOP significantly increased in the headstand position.

“The patient’s IOP increased from 12 mm Hg to 32 mm Hg immediately after inversion and remained stable at that level throughout head-down posturing,” the investigators wrote.

Considering the implications

The studies and reports led investigators to say that they’ll steer glaucoma patients away from Sirsasana.

“We think that patients suffering from glaucoma should be advised against practicing postural (head-down) yoga exercises,” Dr. Bertschinger said.

“Even though we found no correlation with optic nerve damage, the two-fold rise in IOP is alarming, and we suggest no Sirsasana in glaucoma patients and those who are at risk of developing glaucoma,” Dr. Baskaran said. “We recommend all to examine their eyes before performing Sirsasana, especially [those who are] 50 years of age or more, when the glaucoma risk is greater, as in a positive family history of glaucoma in blood relatives.”

“No one can tell us really whether there are health benefits or eye risks with the inverted position, but in patients with glaucoma, this may be a real issue threatening the optic nerve,” said Robert D. Fechtner, M.D., professor of ophthalmology, University of Medicine & Dentistry of New Jersey, Newark. Although it’s not very common to flat-out ask patients if they practice yoga and the Sirsasana posture in particular, the recent reports should prompt ophthalmologists to inquire further when a glaucoma patient says she practices yoga, Dr. Fechtner said. “We’re seeing a lot of different avenues of evidence that the perfusion pressure matters to the optic nerve,” Dr. Fechtner said. “By turning someone upside down, you’re decreasing perfusion pressure,” an area being explored as a risk factor for glaucoma. The latest reports also can be viewed in a larger realm of research regarding inverted positions and IOP, Dr. Fechtner said.

Most recently, this includes studies regarding IOP variation in the daytime in a sitting position versus at night when lying down.

Editors’ note: The physicians interviewed have no financial interests related to their comments.

Contact Information

Baskaran: baskaran.m@gmail.com

Bertschinger: dimiter.bertschinger@hcuge.ch

Fechtner: 973-972-2030, fechtner@umdnj.edu

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