Your eyes get puffy because the skin around the eyes is rather thin and it is also full of blood vessels. This makes it rather sensitive. Many who work on the computer are afflicted with puffy eyes. But this can be treated with some home remedies.
Here are some tips from the website -
http://www.eyecaresource.com/conditions/puffy-eyes/
# Wash face with ice cold water
# Limit sodium intake
# Drink plenty of water to clean out your system
# Place two slices of cool cucumber on the eyes for several minutes
# Moisten two tea bags in cold water, chill them in the refrigerator and place them over closed eyelids for several minutes
# For allergies and puffy eyes, find out the item causing the allergic reaction and minimize its use; doctors may also provide medication in the form of shots or prescription drugs
# Cream for puffy eyes - Try a soothing eye cream with aloe and Vitamin E, which can be applied to the eye