Canine glaucoma refers to a group of diseases in dogs that affect the optic nerve and involve a loss of retinal ganglion cells in a characteristic pattern. An intraocular pressure greater than 22 mmHg (2.9 kPa) is a significant risk factor for the development of glaucoma. Untreated glaucoma in dogs leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.