Is it safe to have a Blepharoplasty if I have glaucoma?

Usually glaucoma is not a contraindication to have blepharoplasty. Evaluation in consultation is necessary. Most important is technique of the eyelid surgery to preserve eyelid function.

Once you have cleared the surgery with your corneal surgeon, an upper blepharoplasty may be done conservatively, but it is important that no orbicularis oculi muscle is removed. Orbicularis oculi muscle is  responsible for closure and blinking of the eyelids and during surgery, most surgeons remove a strip of muscle because it is technically easier than trying to meticulously dissect the skin away alone. Most patients can spare removal of a small strip of muscle so it is usually not a concern.However, patients with dry eye can be susceptible to even the slightest weakening of eyelid closure. You should be aware, that sometimes, despite the most delicate and meticulous surgery, dry eye can become worse. Clearance with your corneal surgeon is of the utmost importance. 

Before proceeding with surgery, I would have a thorough discussion with your glaucoma and corneal specialist to get their view.  If you proceed, do so with caution and conservatism.  Good luck!