Open Angle Glaucoma
In Open Angle Glaucoma, when one looks at the angle or the drainage system of the eye it looks “open.” This is the more common type of chronic glaucoma. In Open Angle Glaucoma, patients generally do not know that they have the disease. It is usually diagnosed on routine examination by finding an elevation of intraocular pressure (the pressure within the eye), or by typical appearance of the optic nerve.
Narrow Angle Glaucoma
The other broad category of the glaucomas is Narrow Angle Glaucoma. Although open-angle glaucoma is more prevalent in the United States, narrow angle glaucoma is still quite common.
The common feature in narrow angle glaucoma is the fact that the anterior chamber, or the front of the eye, is quite shallow. The junction of the iris and cornea, or the “angle”, is where the eye’s internal fluid normally drains. If this angle closes, the pressure inside the eye can become elevated, resulting in damage to the retinal cells and optic nerve.
Narrow angles can be diagnosed by a test called gonioscopy on a routine eye exam in the ophthalmologist’s office. If your ophthalmologist finds that you have a sufficient narrowing of the angle that makes it likely the angle will close in the future, he or she will suggest an iridotomy to prevent angle closure. This is a laser treatment that creates a very small opening in the iris and allows the angle to stay open. This procedure is a quick out-patient procedure that is very safe.
Acute Angle Closure Glaucoma
In acute angle closure glaucoma, the iris and cornea can suddenly come in contact, resulting in a very rapid rise in eye pressure. This typically occurs in one eye and is usually quite painful, sometimes with a severe headache, and can even induce nausea and vomiting. The vision often becomes very blurry, the eye is red and the pupil often reacts poorly. The classic symptom is seeing halos around lights. The onset of symptoms can sometimes evolve in less than an hour, but often happen over several hours.
Acute angle closure glaucoma is an emergency because prolonged periods of high eye pressures can cause irreversible damage to the optic nerve. You must call your eye doctor immediately if any of these symptoms or signs are present.