Traditionally glaucoma has been described as a condition where the pressure inside the eye, referred to as intraocular pressure (IOP), becomes too high and results in damage to the optic nerve with subsequent vision loss. Another way to think of this is your eye has pressure just like your blood. When blood pressure is high, it can damage your blood vessels. When eye pressure is high, it can damage the eye, specifically the optic nerve. The pressure can rise as a result of too much fluid production in the eye or, the inability for it to drain out due to the anatomy of the eye. There are two categories of glaucoma; primary open angle glaucoma and narrow angle glaucoma. Narrow angle glaucoma is relatively uncommon making up approximately 10% of glaucoma cases vs. primary open angle glaucoma which accounts for90% of cases.
Elevated eye pressure alone is not the only cause of glaucoma. Many patients have glaucoma while having what appears to be normal eye pressure. This is referred to as normal tension or low tension glaucoma. This form of glaucoma, which is still in the open angle category, is not completely understood. It is generally believed to occur because of an unusually susceptible optic nerve or reduced blood flow to the optic nerve, causing damage despite a normal intraocular pressure. These blood flow changes can be the result of many different systemic health conditions including hypertension, diabetes, and sleep apnea. Historically these conditions were thought to have some association with glaucoma however, now they are considered significant risk factors.
Research at Kellogg Eye Center, University of Michigan, evaluated the risk rates of glaucoma in various racial groups. In the eye care community it’s well known that African Americans have the highest risk for glaucoma. But the risk for other groups was not as well quantified until a recent review of insurance records was conducted by researchers.
The records were of 2,259,061 eye care recipients aged 40 and over who were enrolled in a managed care network. Among the findings:
Latinos and Asians have roughly the same risk for open angle glaucoma, with both having a little more than half the risk of African Americans.
Asians have the highest risk for narrow-angle glaucoma, with Latinos coming in second.
Normal or low-tension glaucoma rates are fairly low for all groups, but Asians have the highest risk at 0.73 percent twice the prevalence for Caucasians at 0.34 percent.
The study also looked at glaucoma prevalence among Asian subgroups. Notably, those of Japanese origin hada9.49percent prevalence of open angle glaucoma, with Eastern Indians and Pakistanis at 7.78 and 7.70 percent. For narrow angle glaucoma, Vietnamese and Chinese had the highest prevalence at 4.08 and 3.74 percent. For normal tension glaucoma, Japanese had the most risk at 1.99 percent.
Finally, the research in this study demonstrated that with respect to risk, Caucasians were in the lowest percentile of all three types of glaucoma compared to the other racial groups.
In closing, it is important to recognize that glaucoma does not hurt unless you are having an acute angle closure attack. Therefore, 95% of patients can have glaucoma and not have any idea. In addition, glaucoma will not affect your vision until late in the disease so relying on how good you see to determine you do not have glaucoma does not work. It is imperative to have an annual eye health exam to rule out a diagnosis of glaucoma.
If you have any questions concerning glaucoma, or would like to schedule a glaucoma evaluation, please contact our office in Stillwater at 405-372-1715. We also invite you to visit our website at www.cockrelleyecare.com and like us on Facebook at Cockrell Eye Care Center!