Commentary: The impact of yoga practice on glaucoma

Yoga is the most popular form of complementary therapy being practiced to maintain one’s physical and mental wellbeing. While yoga traditionally comprises advice for ethical lifestyle and spiritual practice, it is most often associated with physical postures (asanas), breathing techniques (pranayama), and meditation (dhyana). While these exercises are routinely safe, there are risks involved for certain patients including those suffering from or at risk of glaucoma. The effects of yoga on intraocular pressure (IOP) have been found to be bidirectional, and the exact mechanisms are not yet fully understood.

The authors have reviewed literature to study the effect of yoga on IOP and glaucoma. They have observed a reduction of IOP in patients of glaucoma through Jyoti tratak (candle meditation) and slow yoga breathing exercises and a rapid increase in IOP immediately after head-down posture yoga.[1] Tratak kriya is said to lead to contraction and relaxation of ciliary muscles, which may possibly increase the aqueous humor outflow and subsequently decrease the IOP.[2] Dada et al.[3] have evaluated the effect of yoga and meditation on IOP, quality of life, stress markers, neurotrophins, and gene expression in patients with primary open-angle glaucoma and found an improvement in all parameters.

On the other hand, progressive glaucomatous optic neuropathy and field loss in patients who regularly practiced Sirsasana (Headstand) has also been identified.[1,4,5] Four yogasanas [Adho Mukha Savasana (downward-facing dog), Uttanasana (standing forward bend), Halasana (plough pose), and Viparita Karani (legs-up-the-wall)] showed a 20–73.7% increase in IOP in all study subjects.[1] Yoga with head-down positions was associated with a rapid rise in IOP in glaucoma and healthy eyes and with the body vertical, with a doubling of the IOP, remaining elevated as long as the position was maintained.[1] Mani Baskaran et al.[6] observed a twofold increase in IOP during Sirsasana, which was maintained during the posture in all age groups irrespective of their ocular characteristics. Valsalva maneuver is known to affect IOP; so it is expected that breath-holding yogic exercises are likely to cause IOP elevation. Forced unilateral nostril breathing has also been observed to affect IOP significantly.[7] Rakstyte et al.[8] studied an impact on IOP before, during, and after Matsyasana (fish yoga pose) and found an increased IOP in head- down position which returns to the initial value shortly after. A case series by Mehrdad Malihi et al.[9] to study the effect of different body and head positions on IOP shows a lower measurement while sitting with a neutral neck position and a rise in IOP in all other positions. Acute angle-closure glaucoma attacks often precipitated by prone-position yoga exercises suggest that this position probably increases pupillary block in “at risk” eyes by causing the lens to fall onto the iris, which has been the principle of the prone provocative test for decades.

Certain questions, however, remain unanswered. It is unclear whether yoga has any sustained effects on the IOP and optic nerve. Further research is needed to fully comprehend the mechanisms by which yoga exerts its effects and determine the types, optimal duration, and frequency of yoga practice for glaucoma patients. Future studies are also warranted to ascertain whether yoga-associated IOP changes are associated with parallel changes in perimetry and nerve fiber thickness and changes in cerebrospinal fluid pressure, blood pressure in lamina cribrosa capillaries, and the ocular blood flow.

It is difficult to establish direct causality between different yogic postures and glaucomatous progression, but in patients with pre-existing glaucomatous optic neuropathy, dramatic changes in IOP can definitely be harmful. Inquiring about the practice of yoga in cases of unexplained progression despite an apparently well-controlled IOP can, therefore, be an important consideration. Relaxation and meditative aspects of yoga may help to reduce stress and improve the overall well-being of an individual which can be indirectly beneficial. The key is to “keep the head above the heart at all times.” It is also important to note that yoga should not replace traditional glaucoma treatment but rather be practiced/advised as a complementary therapy and glaucoma patients should consult their healthcare provider before beginning any new exercise or relaxation program, including yoga.