Eyes are the most sensitive part of the human body which has be taken some special care. Here are the ways, by following which you can easily improve your eye sight.
Home Remedy
Take 100grams of rose water and 15-20 grams of dried amla in a bottle and leave it for a maximum of 2 days. Then Filter that liquid with a clean cloth and use it as an eye drop. You can apply 1-2 drops daily twice, morning and evening just before sleep.
The Amla mentioned is also known as Amalaki or Indian Gooseberry, which is a small tree that is indigenous to India. It produces fruit that have been used in ayurveda as a food and a medicine for thousands of years.

Using these eye drops will not only build your eye sight but also cleanses your eyes.
YOGASANA THAT IMPROVES EYE SIGHT

Sarvangasana - (Stand - on - Shoulder Posture)
The word Sarvangasana can be split into 3 parts each having its own meaning as Sarva + Anga + Asana.
Sarva means all
Anga means body parts
Asana is the posture we maintain. Thus the name "Sarvangasana".
How-To Do Sarvangasana:
1. Lie supine over a blanket, keeping the arms stretched above the head.
2. Raise the legs together very slowly and gracefully (without bending at the knees) till it forms about 45º to the ground.
3. Raise the legs further to 90º position.
4. Now raise the buttocks and the trunk also, taking support of the arms and the elbow, without lifting the head. Rest elbows on the ground ground firmly and support the back with both the palms. Straighten the trunk with the hands till the chin is well set in the suprasternal hollow. Now bring the legs parallel to the ground.
5. Keep the body erect stretching it up vertically supporting on the shoulders but relaxing. Maintain for about 2 minutes - 5 minutes. Carefully avoid all the jerks and keep the head on the ground.
Slowly come back to position 1 through 4 to 1
Sarvangasana is not only good for improving Eye sight, but also helps to keep the whole body active and healthy as it tones and maintains the thyroid gland healthy.
Note: Persons with cervical spondylosis should not do this asana.
YOGIC KRIYAS

Trataka (Cleansing the Eyes)
1. Sit in any meditative posture comfortably with an erect spine. Arrange a burning candle with the flame at the same height as the eyes at a distance of about a meter.
2. Start gazing at the flame without winking the eye-lids.
3. Learn to ignore the irritation and watering of the eyes.
4. With practice, the gaze becomes steady, making the mind single-pointed. Relaxation of the eyes is important. Otherwise, excessive strain of the eye-muscles may even cause headache.
5. Progress slowly starting with 10 secs. and increasing the duration by 10 secs. per week.
BENEFITS:
This cleansing process activates the tear glands, purifies the visual system, promotes good concentration and strengthens will-power. Generally it cures eye defects in no time, if done properly.
Hope This Helps...
Try it yourself and experience the benefits.