The Ex-Press Mini Glaucoma Shunt, implanted under a scleral flap, provides a simplified method of filtration surgery for patients with open angle glaucoma. Similar to trabeculectomy, the shunt reduces the intraocular pressure by diverting the aqueous humor from the anterior chamber to the subconjunctival space to form a filtration bleb. Post-op aqueous outflow is controlled by the unique flow-modulating design and the scleral flap. When patients who have already failed one trabeculectomy, or have had multiple other procedures such as corneal grafts, vitrectomy or retinal detachment repair with prior cataract surgery, the option of drainage glaucoma surgery is considered. Preparation of instruments is similar to standard trabeculectomy. Express-shunt is a good alternate drainage glaucoma surgery when the standard trabeculectomy fails.