Glaucoma is a leading cause of irreversible blindness in the United States. Filtration surgery is the procedure of choice when medical therapy or laser trabeculoplasty fail to control the intraocular pressure. In this grant application, a non-invasive laser treatment is proposed as an alternative to filtration surgery. The laser to be used is a Candela flashlamp excited dye laser emitting in the visible region of the spectrum. Because visible light is readily transmitted by the cornea, a fistula will be created by the laser via an ab-interno approach (from within), allowing for controlled egress of aqueous humor from the anterior chamber of the eye and control of intraocular pressure. A slit lamp delivery system will be developed in Phase I of this grant to accomplish ab-interno delivery of laser energy to the eye. The optimum operating parameters for creating a filtration fistula using this system will then be evaluated both in-vitro and in-vivo using an animal model.