I am constantly suffering from eye allergy. in summers mostly i have to use anti allergy(histazoline eye drops). is there any permanent cure of this?

Yes: The best treatment is to see an allergist for specific treatment. Nasal sprays and allergy shots can work to cure this problem much better than applying a bandaid like an eye drop. Oral antihistamines can also help to decrease itching if this is a problem. Histazolin uses a vasoconstrictor, like visine, which is not a good treatment for eye allergy. Zaditor (ketotifen) is better for otc use.

Cure?: Unless you can pinpoint the specific allergen and avoid it (move to another place, get rid of pets, etc), there is no cure and you will have to treat the eye allergy forever. If you have a specific allergy on testing, densensitization can improve symptoms though.