kinjalkishor 
Proper rest and sleep are necessary.
Rest –
As soon as you feel sufficiently tired you must close your eyes and take rest. It is still lot better if you also try to empty your mind also (meditate). If you are enough tired and resting in a peaceful environment, you may get in REM sleep for 5 min in 15 min sleep, which will relax your brain very much (only brain, body can be relaxed by longer sleep only).
Palming is good way to rest your eyes for short periods. Close the eyes gently. Bend the palms in the shape of a cup and place them on your eyes. The palms should not touch or put pressure on eyes, but only cover them completely. The fingers should rest on forehead, and the nose should remain uncovered. You can rest the elbows on knees or a table.
Blinking frequently for 1-2 min also refreshes eyes.
Sleep –
Do not cut on sleep. Take 7-8 hrs sleep daily without disturbance.
If you really wake up at 3 am and cannot sleep till 5 am, you must check your blood sugar (hypoglycemia). One raw Bittergourd juice each night before going to bed for 3-4 weeks will solve this problem. Do not take Tea, Coffee, Chocolates (it is lot better to avoid both completely) or Sweet foods in evening (after 3 pm). It is better to sleep properly and be active and enthusiastic than depending on Tea, Coffee, Chocolates for feeling active.
Cleaning –
Wash eyes with cold clean water.
Put some drops of rose water in eyes, if you feel dust or too much water or irritation in eyes. It will cause burning sensation. Do not use rose water more than once in a day. Eye drops should be used only during infection (not regularly or you may get addicted to eye drops). You can also use rose water mixed with equal amount of water for washing face and eyes.
Doing Trataka once every day will also produce sufficient tears and clean the eyes naturally. Crying also produce tears and relieves from tension, but the point of doing Yoga and Meditation is to control mind and stress so that is not a good option. Too much grief and stress produces harmful poisonous chemicals in body which harms cells and consequently overall health in large amount. Do not expect to be healthy till you calm your mind.
Exercises-
Sunlight – Close your eyes and face towards sun (preferably in morning). Turn your neck left and right slowly and keep it turned for some time to let sunlight fall on all areas of eyes.
Eye Movement – Move Eye balls (see in that direction), Vertically (up and down), Horizontally (left and right), Diagonally, Rectangular movement (make a big imaginary rectangle and trace its corners with eyes in both directions (clockwise and anti-clockwise), Circular movement (clockwise and anti-clockwise)
Focus Exercise – Stretch your hand forward. Raise your thumb, closing the fist with fingers. Fix your gaze at a point beyond your thumb and slowly bring it closer and fix it ultimately on the thumb. Do 2-10 times. Now gradually start bringing the thumb closer to the eyes and repeat the process of looking beyond the thumb and at the thumb. Go on doing it until the thumb comes very close to the eyes. Close the eyes gently and give rest.
When in open areas, look at a close by objects (like thumb near your eyes as much as you can (more than 25 cm) then keep increasing focus to the farthest object (trying to see the nearest and farthest object clearly), first change focus continuously slowly, then change focus in discrete distances (medium speed), then try changing focus continuously with speed.
Trataka – Trataka is the process of looking at a fixed point (Bindu Trataka – Black filled circle (1cm diameter on A4 paper) on white paper (paste it on a wall) looked upon at a distance of 3 feet at eye level, or you can make same size filled circle on a light colored wall with ball pen, but black and white combination is best), Candle light, American Power Circle (see below), flame of small clay cup lamp or candle)) with fullest concentration till tears come to one’s eyes (or when you feel burning sensation in eyes (for people with tired or weak eyes look only till you feel tired and cannot do more). For doing Trataka sit in Sukhasana. Increase the duration of Trataka gradually.
Sukhasana
Food –
Carrots are best for both eyes and brain and also improve night vision. Milk (500 ml each day) and Ghee (1 teaspoonful each day) are great sources of Vitamin A and other vitamins and minerals, good for Eye, Brain, Skin and whole body. Spinach and other fruits and vegetables rich in Vitamin A are also very good.
Again to remind you proper rest and sleep when sufficiently tired is absolutely necessary for great eyesight.
AVOID THESE –
Do not shampoo your hair frequently (do not do more than once per day). Do not let shampoo enter your eyes. The Chemicals in shampoo irritates eyes and make ideal humid environment for fungal infection. If you notice too much Eye Mucus (white viscous liquid discharge), stop shampooing, use eye drops twice a day till you recover. Using Herbal Homemade Shampoo is recommended as it is better for both hair and eyes.