Glaucoma is nicknamed “the sneak thief of sight” because the vision loss is gradual and typically painless. Unchecked, these “sneaky” attributes allow glaucoma to slowly decrease vision without detection by the individual until the loss is severe. Patients rarely schedule appointments with an eye doctor because their symptoms make them suspect they have glaucoma. The diagnosis of glaucoma normally occurs during a comprehensive ocular health examination, rather than by a patient’s vision complaints.
Glaucoma is an eye disease that occurs when your eye pressure damages the optic nerve, a bundle of nerve fibers located at the back of your eye. The optic nerve gathers visual information and sends these cues to the brain to interpret as an image. The liquid that fills the front of your eye is called aqueous, and your eye produces this fluid continuously. As the fluid enters the front chamber of your eye, some of the aqueous must drain out. This requires a constant balance of fluid entering and leaving the eye. If the aqueous fails to drain at the rate needed, this may result in a high eye pressure. Damage to the optic nerve will result in progressive loss of vision. Medications will help reduce eye pressure, but many people wish to also look at the possible benefits of vitamins to control glaucoma.
Vision damage from glaucoma occurs in a slow, tunnel-vision type pattern. As the outer-most peripheral vision gradually declines, it is rarely noticed by the individual until the loss is profound. The visual fields of our two eyes overlap, so if one eye has a deficiency in a particular area, the other eye usually picks up that area, making the brain still perceive vision in that area. Unless the person covers each eye alternately to test the field of vision of each eye, which most people don’t routinely do, it is common to be unaware of significant visual field loss.
Risk Factors for Glaucoma
Primary risk factors include African American or Hispanic descent, age of sixty years older, family medical history of glaucoma, history of steroid use, ocular trauma, high myopia, diabetes, or hypertension. Other risks include high eye pressure, thin corneas, history of eye injury (especially blunt trauma), and suspicious optic nerve (larger nerve center than normal).
Symptoms of Glaucoma
Glaucoma is largely symptom-less, at least until the very advanced stages. However, if the pressure inside the eye is significantly elevated, you may perceive halos around lights. With substantial vision damage, there may be peripheral vision problems or tunnel vision. Individuals suffering with peripheral vision loss sometimes bump into the wall as they go around corners or complain that they don’t notice cars approaching from the side and rear of their car while driving. Except in the rarest types of glaucoma, there usually is no pain associated with this condition.
Causes of Glaucoma
Glaucoma is caused by a problem with the “plumbing” of the eyes. This is an over-simplification, but in line with most of our evolving understanding about the disease. In glaucoma, the pressure inside the eyes is too high for normal tissue function, and this leads to nerve damage, specifically the nerves that carry visual information. Doctors and researchers recognize that glaucoma is likely more complicated than we have understood it to be during the last few decades. Recent research suggests that blood flow to the eyes and the optic nerve’s ability to receive oxygen are also critical factors in the process of glaucoma. While this may eventually lead to breakthroughs in glaucoma treatment, we only have the ability to treat the internal eye pressure. Managing the intraocular pressure is, and has been, the main line of defense for decades, and today’s medications are even more effective than previous generations.
Testing for Glaucoma
No single test allows doctors to arrive at the diagnosis of glaucoma. Multiple complex factors are considered, and the degree each risk factor plays in glaucoma is determined on an individual basis. Findings that include substantial vision loss are “cut and dried” and glaucoma treatment is commenced immediately. However, the most challenging clinical decisions are made when a patient has little or no vision loss but presents with all of the hallmark risk factors and damage may be imminent. Doctors use their knowledge and experience and the clinical findings to determine the diagnosis.
Treatment of Glaucoma
Once the decision to treat glaucoma is made, a number of tools are available to control the disease. Prescription eyedrops are the primary way glaucoma is managed. Intraocular pressure–reducing medications slow down or stop optic nerve damage that leads to vision loss. These medications won’t reverse any vision loss that has already occurred, but they may prevent further loss. There are dozens of prescription eyedrops available, and they each work through different means to achieve the same outcome. Some work to slow down the eye’s ability to produce fluid, and others work by increasing the rate of fluid drainage out of the eye (several prescriptions combine two drugs that use both methods).
Given the common fear about getting glaucoma, and the significant quality-of-life issue that vision loss would entail, the best advice is to make sure that you have an eye examination every year or two at minimum, even if you have no eye problems or don’t wear glasses. A comprehensive ocular exam will spend as much time assessing the overall health of the eye as it does vision. Early detection of glaucoma is essential for preservation of eyesight, and regular eye examinations will allow this terrible eye disease to be stopped in its tracks before it can do serious damage.
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