If you are over the age of 40 and have a family history of glaucoma, you should have a complete eye exam with an eye doctor every year and become well-educated on glaucoma evaluations and treatments. To diagnose glaucoma, an eye doctor will test your vision and examine your eyes through dilated pupils. The exam will also focus on the optic nerve, which has a particular appearance with glaucoma. A complete eye exam includes five common tests for detection. Tonometry measures the pressure within the eye. During tonometry eye drops are used to numb the surface of the eye. A doctor or technician then measures the inner pressure by using a device to apply a small amount of pressure to the eye or by a warm puff of air. The typical range for normal pressure is 12-21 mm Hg. The higher the pressure reading the higher the risk for glaucoma.
What Is Glaucoma?
Glaucoma refers to a group of related eye disorders that all cause damage to the optic nerve that carries information from the eye to the brain. Glaucoma usually has few or no initial symptoms.
In most cases, glaucoma is associated with higher-than-normal pressure inside the eye — a condition called ocular hypertension. But it also can occur when intraocular pressure (IOP) is normal. If untreated or uncontrolled, glaucoma first causes peripheral vision loss and eventually can lead to blindness.
According to the American Academy of Ophthalmology, the most common type of glaucoma — called primary open-angle glaucoma — affects an estimated 2.2 million people in the United States, and that number is expected to increase to 3.3 million by 2020 as the U.S. population ages.
And because most cases of glaucoma have few or no early symptoms, about half of Americans with glaucoma don’t know they have it.
Types of Glaucoma
The two major categories of glaucoma are open-angle glaucoma (OAG) and narrow angle glaucoma. The “angle” in both cases refers to the drainage angle inside the eye that controls the outflow of the watery fluid (aqueous) that is continually being produced inside the eye.
If the aqueous can access the drainage angle, the glaucoma is known as open angle glaucoma. If the drainage angle is blocked and the aqueous cannot reach it, the glaucoma is known as narrow angle glaucoma.
Variations of OAG include: primary open angle glaucoma (POAG), normal-tension glaucoma (NTG), pigmentary glaucoma, pseudoexfoliation glaucoma, secondary glaucoma and congenital glaucoma.
Variations of narrow angle glaucoma include include acute angle closure glaucoma, chronic angle closure glaucoma, and neovascular glaucoma.