Glaucoma is a disease characterized by abnormally high intraocular pressure caused by blockage or disturbance of normal fluid circulation within the eye. Glaucoma occurring in the first 3 years is commonly termed infantile glaucoma, and onset after the age of 3 is often referred to as juvenile glaucoma. The term congenital glaucoma suggests that the disease is present at or soon after birth, although it may be difficult to determine that the disease exists at this developmental stage. The terms primary and secondary are often used in conjunction with the terms infantile and juvenile to communicate the origin of the observed eye disease. Primary glaucoma refers to a disease associated with an embryological developmental anomaly, whereas secondary glaucoma is associated with other ocular or systemic disease. Just as is the case with adult glaucoma, elevated intraocular pressure can result in visual loss and potential blindness, so early detection and treatment are essential.