The pressure in your eye, intraocular pressure (IOP), helps the eye keep its shape and function properly. In a balloon, too much air will cause it to “pop”. In your eye, too much pressure can damage your optic nerve.
Your eyes make fluids that provide oxygen and nutrients to its internal structure. This fluid helps maintain your intraocular pressure. The vitreous fluid fills the structure at the back of the eye, while the aqueous humor fills the chamber at the front of the eye. The aqueous humor is continuously produced and circulated – providing nourishment to the cornea, iris and lens, and eliminating debris.
In a normal eye, the aqueous humor is continually drained through a system, located at the angle where the iris and cornea meet. The fluid passes through spongy tissue called trabecular meshwork. It then drains into the Schlemm’s canal, and merges into the bloodstream.
Sometimes, the drainage system becomes blocked and the fluid can’t drain at its normal rate. When this occurs, your IOP becomes elevated. This can result in ocular hypertension. In addition, it may lead to gradual and permanent damage to the optic nerve. Most importantly, the optic nerve is the only nerve in your body that does not regenerate once it’s damaged.
In most people, the fluid is created and drained at the same rate – producing normal pressure within the eye. Because everyone’s eye is different, normal IOP can range from 8-21.
As the National Eye Institute notes, “Not every person with increased eye pressure will develop glaucoma. Some people can tolerate higher eye pressure better than others. Also, a certain level of eye pressure may be high for one person but normal for another. Whether you develop glaucoma depends on the level of pressure your optic nerve can tolerate without being damaged. This level is different for each person. That's why a comprehensive dilated eye exam is very important.”
For this reason, we recommend annual eye examinations beginning at age 55, or age 40 for patients with a family history of the disease. This will allow your doctor to monitor changes in your IOP and determine what is normal for you.
Primary open angle glaucoma, which is sometimes called chronic glaucoma, is the most common type of glaucoma. According to the Glaucoma Research Foundation, this type of glaucoma affects about three million Americans. It is called “open angle” because the drainage angle between the iris and cornea are open, but the fluid is not draining properly. There is a blockage somewhere in the drainage system, similar to a clog in your kitchn sink.
Since your eye is continuing to create fluid faster than it is draining out, your IOP becomes elevated. Over time, this elevated pressure will damage your optic nerve. But, the process is so slow and painless, you may not even be aware of a problem. It has been called a slow thief because it gradually robs you of your vision. This type of glaucoma usually affects both eyes, although it may first start in one eye. If left untreated, you can develop tunnel vision and eventually lose all sight.
Overview of Glaucoma
Open Angle Glaucoma
Medical Treatment for Open Angle Glaucoma
Laser Treatment for Open Angle Glaucoma
Surgery for Open Angle Glaucoma
Narrow Angle Glaucoma
Laser Treatment for Narrow Angle Glaucoma
Neovascular Glaucoma
Inflammatory Glaucoma
