What Is Glaucoma & Where Did It Originate From?

Glaucoma is now believed to be the end product of a number of distinct structural and systemic diseases characterized by high pressure inside the eye and optic nerve damage. This pressure can damage and even kill the sensitive nerve cells in the back of the eye, causing loss of sight. Glaucoma is not a new disease. The ancient Greeks gave us the term glaucoma, which they used to describe all eye diseases leading to blindness. In the first several centuries A.D., cataracts, which are amenable to treatment, began to be distinguished from glaucoma, which could not be treated. The association of glaucoma with increased pressure in the eye is often attributed to Richard Banister, an English oculist and author of the first book on ophthalmology in English, who made this observation in 1622 . Banister noted that if you felt an eye with glaucoma by rubbing on the eyelids, the eye felt more hard and solid than normal.

Today, a diagnosis of glaucoma is based on three factors: intraocular pressure (IOF), the pressure within the eye, which is typically elevated; characteristic changes in the visual field, specifically a loss of peripheral vision; and signs of damage to the optic nerve. Very often the first indication that glaucoma may be present is an increase in IOP. Since the 1930s, eye doctors have distinguished between two primary forms of the disease: open-angle and narrow-angle glaucoma. These determinations were based on the width of the angle formed by the meeting of the iris and the cornea. Grades I and II glaucoma (glaucoma in the presence of 10-degree and 20-degree angles, respectively) were designated narrow-angle glaucoma; grades III and IV glaucoma (glaucoma in the presence of 30-degree and 40-degree angles, respectively) were termed open- angle glaucoma.

Angle-closure glaucoma - glaucoma caused by a narrow angle and/or close proximity of structures within the eye to each other - may be considered a structural problem. Open-angle glaucoma is divided into a number of different varieties. The most common type of glaucoma is primary open-angle glaucoma. The other glaucomas that make up the open-angle family are variously called structural or secondary, or glaucoma as an end product of a disease.

Today, researchers have recorded more than a dozen distinct forms of glaucoma, and there may be more. Some scientists claim that they can differentiate between as many as forty different types of glaucoma. Although primary open-angle glaucoma accounts for the majority of cases of glaucoma, many people do have other forms. As the differences among glaucomas become clearer, and the root causes are better identified, researchers may be able to develop specific treatments for controlling each individual type of glaucoma.