There are several types of Glaucoma, which form a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. The optic nerve, which is a bundle of about one million individual nerve fibers, transmits the visual signals from the eye to the brain.
The key to fighting Glaucoma is early detection and treatment to protect your eyes against serious vision loss.
The most common form of Glaucoma, Primary Open-Angle Glaucoma, is associated with an increase in the fluid pressure inside the eye.
With the many types of Glaucoma comes many theories about the causes of Glaucoma, although the disease is usually associated with an increase in the fluid pressure inside the eye.
Traditionally, pressure in the eye has been an indicator that Glaucoma could be present. But for the past several years, patients with no pressure in their eyes have also been diagnosed with Glaucoma.
“For years, we’ve had patients with normal pressure in the eye develop vision loss from Glaucoma and it didn’t make sense because the pressure in the eye was perfectly normal,” explains Dr. Larry Malashock, one of six optometrists at Malbar Vision. “But there is a category of Glaucoma now that’s called Normal-Tension Glaucoma, where the pressure in the eye is fine. It’s just that patients have other structures in the eye that are going bad in a similar vein, which is caused by a lack of oxygen to the retina.”
Among the types of Glaucoma are:
• Primary Open-Angle Glaucoma – This is the most common form of Glaucoma and results in an increase in the amount of fluid in the eye and a gradual build-up of pressure in the eye.
• Angle-Closure Glaucoma – A less-common form of Glaucoma, this type is caused by a rapid or sudden increase of pressure inside the eye, and is a medical emergency that can cause rapid vision loss.
• Secondary Glaucoma – This type of Glaucoma occurs as a result of an injury or eye disease. It may be caused by a variety of medical conditions, medications, physical injuries and eye abnormalities that result in optic nerve damage and vision loss.
• Normal-Tension Glaucoma – In this form of glaucoma, eye pressure remains within what is considered to be the “normal” range, but the optic nerve is damaged nevertheless.
There are several tests and exams that help detect Glaucoma, including:
• Visual Acuity Test – An eye chart test that measures your eyesight at various distances.
• Visual Field Test – Measures your peripheral vision
• Dilated Eye Exam – Drops are placed in your eye to widen, or dilate, the pupils so that the optometrist can examine your retina and optic nerve.
• Tonometry – This measures the pressure inside the eye by using an instrument called a Tonometer.
• Pachymetry – A numbing drop is applied to your eye so your doctor can measure the thickness of your cornea.
Glaucoma treatments include conventional surgery, medicines, laser trabeculoplasty or a combination of any of these. While these treatments may save remaining vision, they do not improve sight already lost from Glaucoma.
To learn more about glaucoma visit the American Optometric Association website.