Are there physical techniques to relieve eye strain? I asked a question about eye strain Does looking into a mirror relieve eye strain in a similar way to looking at distant objects?.

Are there any physical exercises or techniques that can help to alleviate eye strain?

Is there any evidence to support this, if so please provide citations?
EYE RELAXATION


Sit comfortably, close your eyes and cover them with your palms. Be sure that both palms are cupped and do not press on the eyes. Imagine the blackness getting darker and darker. Rest in this manner for five minutes at a time, at least thrice a day.
Stand upright in front of an open window, preferably overlooking greenery. Keep your feet a foot apart, let your arms hang loosely at the sides and be as relaxed as possible. Gently oscillate your body from side to side like a pendulum.
Raise your heels alternately, keeping toes firmly on the ground. Gently swing the whole body to and fro without bending at the waist or hips. Start the exercise with eyes open. Swing like this for a minute and then close your eyes gently, while still swinging. Imagine the apparent movement of the window as clearly as possible.
Open the eyes after a minute and continue this exercise for 10 minutes, alternately closing and opening the eyes. Repeat this exercise at least thrice a day.
Close your eyes and, facing the sun, move your head slowly from side to side. Sun rays cause a rushing of blood to the eyes, relaxing optical muscles and nerves. Do this exercise for 10 minutes thrice a day.
Take a handful of cold water and, bending forward, splash your eyes rapidly, several times. Do not forget to hold water in your mouth while splashing eyes as this cools them down to their nerve ends and freshens them a great deal.


EXERCISES FOR EYE MUSCLES


Sit erect in a comfortable position. Keep your head and neck as relaxed as possible. Gently move your eyes up and down 10 times. The motion should be very slow, uniform and effortless, without moving the head or neck. Let your eyes see as far up and as far down as possible without causing strain. As the eye muscles relax, you will be able to look lower and higher. Repeat this exercise five to six times in a sitting. You can add to the relaxation by resting your eyes in your palms in-between.
Sitting in the same posture as before, move your eyes from side to side. Repeat 10 times. The motion should be very slow, uniform and effortless without moving the head or neck. As in the earlier exercise, you will able to move them farther and more easily with practice. Repeat this exercise five to six times.
Move your eyes gently and slowly around in a circle five times, alternating between clockwise and anti-clockwise motions. Rest for a second and repeat the process five times. Remember that it should be done slowly and effortlessly.
Sit on a terrace where you can see far off objects on the horizon. Look at a distant object and then look at the tip of your nose. Look from one to the other object 10 times. Close your eyes for a second and resume the exercise. Repeat five times and rest your eyes. 


The following exercises may be used to alleviate eyes strain

Bhastrika Pranayam (Breath holding exercise)– 2 to 5 minutes.
Kapalbhati Pranayam (Skull shining breath exercise).
Bahya Pranayam (External breath exercise).
Anuloma – Viloma Pranayama (Alternate nostril breathing exercise).


All these can be found here

Yoga- The name popular in West is actually a derivation from the word YOG (which is a Sanskrit word with meaning 'to combine together'). Yog means to combine one's being with the Supreme Power. Sage Patanjali (Pronounced as Paa+ ta + n + ja + li) brought together postures and techniques of breathing together and created Yog Sutra. (The thread of Yog).

This actually transcended from the ideology that a healthy person can understand the meaning of God and compassion better. Therefore, it aims at relieving a man of the diseases so that a healthy body can provide shelter to a healthy soul.

But Yog is trying to handle a Lion. It should be practiced under the guidance of a learned Yog teacher...