Glaucoma
Overview
Glaucoma is a group of eye diseases which result in damage to the optic nerve and can cause vision loss. The disease can be divided into two main types: open-angle glaucoma and closed-angle glaucoma. Both types are characterized by increased pressure within the eye, but they differ in their onset and progression.
Etiology
The exact cause of glaucoma is not known, but it is believed to be related to increased pressure in the eye. This pressure, known as intraocular pressure, can damage the optic nerve, which transmits images to the brain. If the damage continues, glaucoma can lead to permanent vision loss.
Pathophysiology
In a healthy eye, a clear fluid called aqueous humor circulates inside the front portion of the eye. To maintain a constant healthy eye pressure, an equal amount of this fluid flows out of the eye through a drainage system. In people with glaucoma, the fluid drains too slowly or not at all. This leads to fluid build-up, causing the pressure inside the eye to increase. Over time, the increased pressure can erode the optic nerve tissue, leading to vision loss or blindness.
Types of Glaucoma
There are several types of glaucoma, including:
Open-Angle Glaucoma
Open-angle glaucoma, the most common form of the disease, involves an increase in intraocular pressure over a long period of time. The increase in pressure occurs slowly and painlessly, and vision remains normal until the disease has significantly progressed.
Angle-Closure Glaucoma
Angle-closure glaucoma, also known as closed-angle glaucoma, is less common but can cause a sudden buildup of pressure in the eye. Symptoms can include severe eye pain, nausea, redness in the eye, seeing colored rings around lights and blurred vision. This is a medical emergency and should be treated immediately to prevent blindness.
Normal-Tension Glaucoma
In normal-tension glaucoma, the optic nerve becomes damaged even though the pressure in the eye is not very high. The reason for this is unknown.
Secondary Glaucoma
Secondary glaucoma is a form of the disease that results from an injury or other eye disease. It can be caused by a variety of medical conditions, medications, physical injuries, and eye abnormalities. Infrequently, eye surgery can lead to secondary glaucoma.
Diagnosis
Glaucoma is diagnosed through a comprehensive eye exam. Several tests will be performed, including a visual field test to measure peripheral vision, a visual acuity test to measure how well you see at various distances, and a dilated eye exam where drops are placed in your eyes to widen, or dilate, the pupils.
Treatment
There is no cure for glaucoma, but early treatment can often control the disease. This makes early diagnosis and treatment important to protect your sight. Most people with glaucoma who follow their treatment plan and have regular eye exams are able to keep their vision.
Prognosis
The damage caused by glaucoma cannot be reversed, but treatment and regular checkups can help slow or prevent vision loss, especially if the disease is detected in its early stages.