What is glaucoma?
Glaucoma is a disease that causes damage to the optic nerve, which sends signals from the eye to the brain. Glaucoma is usually associated with increased eye pressure (intraocular pressure or IOP); a variety of causes can lead to elevated eye pressure. The treatment of glaucoma involves lowering the eye pressure with eye drops, laser surgery, and glaucoma surgery. One of the most exciting new advances in glaucoma is minimally invasive glaucoma surgery (MIGS), including the creation of devices such as the iStent. These new devices allow eye surgeons to lower the eye pressure in a safer and more controlled fashion. Dr. Potthoff has years of experience implanting the iStent.
Do I have glaucoma?
Glaucoma is a complex disease. There is no one single test that can definitively say that a person has glaucoma. Your eye doctor uses many pieces of information to determine if you might have glaucoma.
Dr. Potthoff’s initial method of determining if a patient has glaucoma is by examining your optic nerve as part of a dilated eye exam. When a patient has glaucoma, their optic nerve will show changes, such as thinning of the rim of nerve tissue on the outside of their optic nerve. Small spots of blood, or hemorrhages, can also appear on the optic nerve when glaucoma damage is occurring.
Another clue in the diagnosis of glaucoma is your eye pressure, or IOP (intraocular pressure). The normal range is between 10 and 21, so if your eye doctor measures your eye pressure and it is above this range it may mean you are at risk for glaucoma. The eye pressure is measured with different devices that press on your cornea, and each patient has a different thickness to their cornea. As such, your eye doctor will likely measure your central corneal thickness (CCT) when he is determining if you might have glaucoma.
The fluid in the eye is resorbed by the body through tissue at the “drainage angle” in the front of the eye. Changes or closure of all or part of this angle can lead to an increase in IOP and cause glaucoma damage. Your eye doctor can examine your angle by performing gonioscopy, which involves using a handheld mirrored lens to examine your drainage angle.
One of the most common ways to test for glaucoma is by using visual field testing. Because of the anatomy of the optic nerve, when it is damaged in glaucoma it can cause specific visual field changes, or defects. These visual field changes are often in a patient’s peripheral vision and can easily go unnoticed by the patient. This is one of the reasons everyone should have a periodic eye exam, most patients who develop glaucoma don’t know they have it!
Dr. Potthoff uses a Haag-Streit Octopus visual field machine to check his patients’ visual field. This state-of-the-art machine is both faster and more accurate than anything else on the market. In addition, Dr. Potthoff administers all of his visual field tests himself instead of delegating to a technician, which insures the most accurate testing possible.
One of the new and exciting developments in the field of glaucoma is the use of OCT (optical coherence tomography) to help in the diagnosis of glaucoma. An OCT machine can measure the nerve tissue in the optic nerve to look for glaucoma damage. This information can help your eye doctor both diagnose and manage glaucoma.