My mother is 62 year old recently she have gone through cataract operation of her left eye and after operation doctor says that her eye is in good condition and operation is completely successful but my mother usually complains pain and piercing in her operated eye.We have consulted two doctor and both are saying that eye is fine and may be due to dryness can be the cause of this so can u suggest what is actual cause and treatment for this.She is feeling so discomfort in her eye.