Glaucoma can be defined as a complex, multifactorial condition in which the flow of aqueous humor in the eye is impeded by an intraocular abnormality, resulting in increased intraocular pressure (IOP) to a level incompatible with normal optic nerve and retinal function1. Glaucoma can be categorized into primary and secondary glaucoma. Distinguishing between the two is important in terms of treatment and prognostic factors1. While medical and surgical therapies remain the mainstays of treatment, primary glaucoma usually ultimately results in bilateral vision loss. This paper will review one case of primary glaucoma in a dog that was treated with gonioimplantation to control intraocular pressure in the left eye. Additionally it will discuss clinical signs, treatment plans and prognosis of primary and secondary glaucomas overall.