Hi Sarala

I used to have this problem during studying. Since I used to study late night and I am not an ardent fan of cucumber, I used to keep two spoons in the freezer for 10 minutes. When it gets cold, I would keep the bent end of the spoons to my eye lids and relax. It gave the same result of that of cucumber!

Another thing why there is dark circles is due to lack of circulation of blood and oxygen and this is restricted when we frown,when we are angry, when we strain our eyes to read something, when we don't blink for a long time, etc. The recovery time for eyes to come to normal stage is longer; hence we are advised not to use many beauty products near the eyes or skin products near the eyes.That is why even when boxers punch in the eyes, it becomes black and dark!!!!

Moreover due to lack of water also our eyes are strained, Since you are already taking more glasses of water each day try adding one more glass for your eyes :)

I hope this helps!