Glaucoma – Essential Facts

WHAT IS GLAUCOMA

Glaucoma is an eye disease from which 60 million people worldwide suffer from. In the US alone, 3 million people live with it, is a leading cause of blindness, and as much as 50 percent of them don’t know that they have it  It is a disease that damages the bundle of nerve fibers that transmit information from the eye to the brain (optic nerve). If left untreated, it can happen without warning and will start the individual on the path to loss of vision and blindness.

This is the very reason that periodic eye exams are necessary. If glaucoma is discovered early, surgery and medication can stop the wrath of glaucoma from fully developing in nearly 9 out of 10 cases. Early discovery and cure can preserve your sight. At present, when vision loss happens, it is permanent. There are still no advances that replace vision loss. The sad truth is that optic nerves will not grow back, which is unlike other cells in the body. To prevent glaucoma from taking over your life, aside from the regular eye exams, when you notice something wrong with your vision, go to the eye doctor immediately. If you act too late, glaucoma could have already damaged the optic nerve, which causes permanent vision loss. It starts with the loss of side vision or peripheral vision. This marches on until damage to the optic nerve is complete.

WHO ARE AT RISK?

  • Anybody at any age could have glaucoma, but the following profiles can be at higher risk:
  • Hispanic or African American ethnicity
  • Hereditary factors like having glaucoma in the family
  • Upon reaching 60 years for all or 40 plus years for African Americans
  • Unusual looking optic nerve
  • Thin corneas
  • IOP or High Intraocular Pressure
  • Risk factors like diabetes, high blood pressure, severe nearsightedness, eye surgery, eye injury, and the use of corticosteroids

HOW DOES GLAUCOMA DAMAGE SIGHT?

The eye produces aqueous humor, a fluid, which goes around the eye frontage to nourish and cleanse the tissues. The aqueous humor goes through an opening near the lens and it drains in the trabecular meshwork, which is a spongy area.

With regards to the aqueous humor, there should be an appropriate balance between the quantity that is produced, and the quantity that departs from the eye. Problems happen when the eye doesn’t properly drain the fluid. There might be other reasons why excess fluids back up. When these abnormalities happen, that’s when IOP or Intraocular pressure occurs, at a rate of over 21 mm Hg (millimeters of Mercury) which is already above normal.

This increase in IOP, gradual or sudden, can compress the area behind the eye, where a bundle of nerves goes out of the eye going into the brain. This pressure damages the optic nerves, first the outer layer (the signal carrier for peripheral vision), then finally to the central vision providers which are the inner layers. Vision loss will start to happen, first, the edges will be darkened. It will build up in size, creating a tunnel-like effect that builds in size if left untreated.

The purpose of treatment for glaucoma is to normalize the IOP pressure in the ocular areas before the nerve damage is untreatable. Those with high-risk factors (as stated previously), should be monitored carefully, and treatment should start as soon as possible. But sadly, there are types of glaucoma that can happen even to people with normal pressure or don’t exhibit high-risk features. But these are rare.

TYPES OF GLAUCOMA AND THEIR SIGNS

Open-Angle Glaucoma. This accounts for 70 to 90 percent of all glaucoma cases. What makes them dangerous is there are no noticeable signs in the early stages, so regular eye checkups are important. IOP is the most usual reason why glaucoma developed. Other reasons could include structural defects, advancing age, and trabecular meshwork/drainage system damage.

Angle-Closure Glaucoma – A generally inherited disease, and is the most common type occurs when the passageway angle is too narrow, and the aqueous fluid can’t drain normally. This type can occur in two ways:

Acute angle-closure glaucoma begins suddenly when the normal flow of aqueous humor between the iris and lens is blocked. Common symptoms can include; nausea, vomiting, seeing halos around light, and blurred vision. This is a medical emergency, resulting in blindness within one or two days if left untreated.

Chronic angle-closure glaucoma progresses more slowly and can damage the eye without symptoms, similar to open-angle glaucoma

Subtypes of Both Open Angle and Angle Closure Glaucomas:

Low Tension Glaucoma – Despite normal IOP, damage still inflicts the optic nerve and cause vision loss. It may be due to poor blood flow happening within the optic nerve or too much sensitivity to pressure.

Congenital Glaucoma – An inherited condition addicting infants, born with angle-closure defects in the eye.

Juvenile Glaucoma – An open-angle Glaucoma affecting children up to young adults.

Secondary Glaucoma – It can be open-angle or angle-closure, and can be triggered by other medical conditions from the eye or even the body. Examples are pigmentary glaucoma wherein the iris or lens pigment granules go off and are transposed into the aqueous fluid. There is also neovascular glaucoma wherein drainage channels are blocked by unusual blood vessel growth. And finally, andiridocorneal endothelial syndrome (or ICE) where cornea cells break off and block drainage.

SCREENING AND DIAGNOSIS OF GLAUCOMA

It is recommended that adults 18 to 60 years old should have eye checkups once every two years. Those above 60 should have an annual checkup. Rigidly follow your doctor’s instructions, whether or not you are at high risk for glaucoma. At the clinic, they will place special eye drops which will enlarge your pupils temporarily. This gives the doctor a good view of the inside of your eye. It allows him to see if there is optic nerve damage, and also for corneal thinning. These are both glaucoma symptoms.

Also to be undertaken is an IOP measurement with a tonometer. It is called the puff test. If the eye doctor finds something wrong, he will recommend you begin treatment or you will have to go back for further tests.

Additional tests may include:

Imaging Records for Optic Nerve which may have to be done over time to monitor the progression of glaucoma.

Another test is Visual Field Testing which is a program to evaluate both central vision and peripheral vision.

Visual Acuity Test – Measure sight, whether corrected or not corrected, for various distances with an eye chart. This is a test for prescribing or updating corrective lens prescriptions.

WHAT TYPES OF EYE DOCTORS TO SEE

Ophthalmologists are certified physicians who have completed postgraduate training for a minimum of 8 years. They can prescribe drugs and execute surgery. Some of them add one year of training for a subspecialty in glaucoma.

Optometrists are licensed doctors who have had postgraduate training of 4 years. In most states, they are accredited to prescribe medicine. They can also take additional studies to authorize them to treat glaucoma.

When you choose your physician, they are usually the available eye specialists in your area. If you are already comfortable with your existing eye doctor, stay on. But if the glaucoma is in the latter stages, you might have to seek recommendations for a glaucoma subspecialist. You might even need a team of medical and emotional support professionals and groups who will work with your main doctor. They could be low vision rehabilitation specialists, community support groups, and even your closest friends and family members.

LIVING WITH GLAUCOMA

Glaucoma is a chronic disease that has to be managed over a lifetime. Discuss all treatment options whether it is managing your diagnosis with medication, or sometimes surgery is used. Determining which option is best for you should be discussed with your doctor at Vision Center of New York.  Along with treatment to protect your vision, you may need to make other daily adjustments to meet daily challenges. Try to maintain a healthy weight and normal blood pressure, control other medical conditions, and get daily exercise. Over time, you will learn the best ways to cope with glaucoma and lead a full and happy life.