These eyeball movements provide balance for people who do work up close, like students who spend a lot of their time reading or working at computers. According to Robert Abel, author of The Eye Care Revolution (Kensington Books, 1999), these brief exercises "compensate for overdevelopment of the muscles we use to look at near objects."

You might be surprised to learn that the palming part of this exercise provides more than a pleasant respite. According to Abel, our photoreceptors break down and are reconstructed every minute. "The eye desperately needs darkness to recover from the constant stress of light," he says. "And the simplest way to break eye stress is to take a deep breath, cover your eyes, and relax."

Along with palming, yoga in general benefits the eyes by relieving tension. While the effect of yoga on the eyes has not been scientifically measured, studies have shown that a simple exercise like walking can lower pressure in the eyeball by 20 percent.

Vasanthi Bhat, a yoga teacher in the Sivananda tradition, includes asanas like Adho Mukha Svanasana (Downward-Facing Dog), in her video, Yoga for Eyes. "These asanas bring circulation to the face, neck, and shoulders, which need to be energized and relaxed for improved vision," Bhat explains. So even if you have not been doing asanas specifically for your eyes, your overall yoga practice is helping your vision.

Looking High, Looking Low

Once students have mastered the basic eyeball exercise, Srinivasan introduces an intermediate series of eye exercises which he calls "shifting focus."

While sitting relaxed and still, pick a point in the distance and focus on it. Extend your arm and put your thumb right underneath the point of concentration. Now begin shifting your focus between the tip of your thumb and the faraway point, alternating rhythmically between near and distance vision. Repeat the exercise 10 times, then relax your eyes with palming and deep breathing. As you practice this exercise, you are training an organ called the ciliary body, which adjusts the lens of the eye. Habitual focus patterns degrade the ciliary body's natural flexibility. Shifting focal points counteracts this stiffness by exercising the organ through its full range, much as we work complementary muscle groups in asana practice.

The final eye asana taught in the Sivananda series stresses close-range focus. As in the shifting focus exercise, gaze at your thumb with your arm extended. This time move the thumb slowly toward the tip of your nose. Pause there for one second. Then reverse the sequence, following the thumb with your eyes as you extend your arm again. As before, repeat the sequence 10 times, then relax with palming.

By training the eyes to focus on the ajna chakra (the "third eye," located between and just above the eyebrows) a yogi trains his mind to turn inward. On a more prosaic level, close-range focus exercises can forestall the need for reading glasses.

Perhaps you've seen a picture of a yogi staring at a candle flame. If so, you've seen trataka, an eye-cleansing exercise described in the Upanishads and mentioned in other yogic texts, including the Hatha Yoga Pradipika. Trataka can also be found in the texts of Ayurveda (traditional Indian medicine), where it is recommended to stimulate the alochaka pitta, the energy center related to sight. But as always with yoga, there's a connection between physiology and the more subtle aspects of spiritual practice. According to Dr. Marc Halpern, founder and director of the California College of Ayurveda, the practice of trataka decreases mental lethargy and increases buddhi (intellect).

Although traditionally performed with a candle, trataka can use almost any external point of focus, like a dot on the wall. Concentrate your gaze on one object, without blinking, until your eyes begin to tear. Then close your eyes and try to maintain a vivid image of that object for as long as possible. Each time you practice trataka, extend the time you maintain the after-image. This exercise, traditionally believed to remove any disease from the eyes and to induce clairvoyance, also develops the skill of internal visualization.Yogis develop this skill to keep their minds fixed in meditation on a sacred image—and, by extension, on the divine experience associated with that image. The intricate spiritual mandalas you may have see in Indian and Tibetan holy books are also designed for this purpose. Highly skilled meditators can visualize even the most minute details of these elaborate cosmic representations. By perfectly aligning inner and outer focus, these yogis seek a realization like that of Meister Eckhart, a thirteenth-century Christian mystic who once declared, "The eye with which I see God is the same eye with which God sees me."

With benefits ranging from better vision to increased concentration and spiritual insight, these eye asanas will enhance your yoga practice. Along with a healthy diet and regular exercise, they will help protect your vision from the stresses of light, tension, and environmental toxins. So as you grow older, and hopefully wiser, you can direct a soft, insightful gaze at the world, learning to see self and other as one.