 Continued use of glaucoma drops can alter the outer surface of the eye and result in swelling and irritation, changing the structure of the eye. This structural change has been found to be a significant risk factor for the failure of glaucoma surgery. A comparison of how well patients do after glaucoma surgery depending on whether they use Restasis the only prescription medication approved by the FDA for treating dry eye or artificial tears which can be purchased without a prescription for 6 months following their surgery. 