Glaucoma is a condition that is one of the leading causes of blindness. The word “glaucoma” refers to disorders that damage the optic nerve; there are several different types of glaucoma that have different causes. The optic nerve is the nerve at the back of the eye that carries visual information from the retina of the eye to the brain to be processed in the visual cortex. The damage to the optic nerve involved in glaucoma is usually due to a pressure inside the eye (intraocular pressure) that is too high.
Glaucoma has a variety of different causes, but certain risk factors make a person more likely to suffer from glaucoma. Glaucoma is more common in older individuals. The condition is also more common in African Americans, Asians and Hispanics than in Caucasians. Individuals with diabetes, heart disease and hypertension are more likely to develop glaucoma than individuals without these conditions. Some injuries and medical conditions affecting the eye may also increase the risk of developing glaucoma, as does prolonged use of corticosteroids to treat other medical conditions.
There are four types of glaucoma. The most common type of glaucoma is chronic glaucoma, also called open-angle glaucoma. The cause of open-angle glaucoma remains unknown, however, and in this condition there is a slow build-up of intraocular pressure that may go unnoticed for a long time. This condition does not cause pain. Over time, peripheral vision decreases, leading to the development of ‘tunnel vision.’ By the time that symptoms of open-angle glaucoma develop, serious damage to the optic nerve has already occurred.
Acute glaucoma, also called angle-closure glaucoma, is caused by a sudden blockage that prevents excess fluid from being drained from the eye. If the fluid can not drain properly, intraocular pressure builds up extremely quickly. If the condition is left untreated, a person may go blind from optic nerve damage within the course of a day. Unlike chronic glaucoma, this condition can cause severe eye pain. Acute glaucoma can also cause vision symptoms, such as loss of vision, blurry or cloudy vision and the presence of “halos” around light sources. A person with acute glaucoma may also feel nauseated and feel like their eye is swollen. Acute glaucoma should be treated as a medical emergency.
Congenital glaucoma is glaucoma that is due to birth defects affecting the eye. Congenital glaucoma is usually noticed weeks or months after birth. Symptoms of congenital glaucoma include enlargement of the affected eye(s), a visible cloudy appearance to the affected eye(s), light sensitivity, red eye and excessive tear production.
Secondary glaucoma is a general term for glaucoma that is caused as a side effect of a drug, an infection of the eye, a systemic disease, such as diabetes, or trauma to the eye. The symptoms and treatments for secondary glaucoma vary based on the cause of the glaucoma.
Chronic glaucoma is treated with eye drops that increase fluid drainage from the eye and reduce the pressure inside of the eye. Chronic glaucoma must be treated for the rest of a person’s life, because there is no cure for the condition. In some cases, laser treatments or surgery may be recommended. Acute glaucoma must be treated immediately to prevent blindness. Treatments for acute glaucoma include eye drops, oral or intravenous medications and surgery to relieve pressure on the optic nerve by allowing some of the excess fluid to drain from the eye. Congenital glaucoma is treated with surgery to correct the eye defect that is causing the glaucoma. Secondary glaucoma may be treated with eye drops and medications, but it is also important that the underlying disease or condition is addressed.