January is Glaucoma Awareness Month. According to the American Glaucoma Society, approximately three million Americans have glaucoma, although many more cases may go undiagnosed. The National Eye Institute projects this number will reach 4.2 million by 2030 — a 58% increase.
What is Glaucoma?
Glaucoma is an eye disease that occurs when the optic nerve, the “cable” connecting the eye and the brain, is damaged. Commonly, this is the result of prolonged elevated eye pressure, called intraocular pressure (IOP). One possible cause of the increase in pressure is an excess of fluid in the eye, either because too much fluid is being produced or due to a drainage problem.
Glaucoma is the second leading cause of blindness and the leading cause of irreversible blindness worldwide. Glaucoma is called "the sneak thief of sight,” as there are no symptoms and once vision is lost, it's permanent. As much as 40% of vision can be lost without a person noticing.
There is no cure for glaucoma, which can lead to blindness if left untreated. Most vision loss from glaucoma can be prevented with early detection and medical intervention. Typically, patients regulate their intraocular pressure with daily eye drops, while others may require more advanced treatment with lasers or surgery. The best way to protect your sight from glaucoma is to get regular comprehensive eye examinations by a licensed eye care professional.
Glaucoma and Yoga Inversions
Inverted poses in yoga, such as downward dog and headstands, have been found to dramatically increase intraocular pressure in the eyes. For most individuals, this rise in eye pressure isn’t a big deal; however, for those diagnosed with glaucoma or ocular hypertension (elevated eye pressure without glaucomatous damage), increasing IOP is a major concern -- especially considering new research indicates that IOP continues to stay elevated even after the individual has returned to an upright position. Therefore, if you have been diagnosed with glaucoma or ocular hypertension, it is best to avoid inverted yoga poses.
The Risk of Inverted Positions
A 2013 study from Mt. Sinai Health Systems compared eye pressure in people with no eye-related disease and glaucoma patients as they performed a series of inverted yoga positions, to measure the increase in IOP and how long the increased pressure lasts. The subjects held each pose (*poses listed below) for two minutes. The researchers measured their IOP five times: before they began (the baseline), as soon as they assumed the pose, two minutes into the pose, seated immediately after the pose, and 10 minutes after the pose.
The pressure was seen to increase markedly from the baseline as soon as the subjects began the poses, but did not go up much more by the two-minute mark. When the measurements were taken after the subjects returned to a seated position and again after waiting 10 minutes, the pressure in most cases remained slightly elevated from the baseline. The difference in elevated IOP between the glaucoma and control groups was not statistically significant, but people who already have glaucoma are more at risk from IOP increases. The greatest increase in IOP occurred during downward facing dog.
*The following four poses were studied and found to cause an increase in IOP:
1. Downward Facing Dog (adho mukha svanasana)
2. Standing Forward Bend (uttanasana)
3. Plow (halasana)
4. Legs up the wall (viparita karani)
Based on this information, it is believed that other inverted positions may pose a similar risk and should also be avoided:
3. Shoulder Stand
4. Forearm Stand
How Should I Modify My Yoga Routine?
Because of these findings and as a precautionary measure while more research is being conducted, it is probably best for yoga enthusiasts with glaucoma to adjust their routines. This doesn’t mean that people with glaucoma cannot practice yoga, only that they should implement some small modifications to their routines in order to eliminate inverted positions.
Here are a few examples of glaucoma-friendly yoga routines:
Mount Sinai Health System. "Certain yoga positions may impact eye pressure in glaucoma patients." ScienceDaily. ScienceDaily, 7 January 2016. www.sciencedaily.com/releases/2016/01/160107105234.htm