Little by little, it painlessly pillages eyesight with the cunning of a bandit. The loss of vision isn’t apparent to the victim until it reaches the optic nerve, which is responsible for transmitting visual information to the brain.
By that point, the damage is irreparable. Glaucoma, the so-called sneak thief of sight, has taken its toll.
Glaucoma is generally the result of a number of diseases that build up fluids within the eye, thereby increasing the internal pressure. Damage begins in the off-center parts of vision, and if left untreated, the condition leads to tunnel vision and blindness.
Columbia resident Jeanie David, 62, said she is well aware of the importance of getting regularly screened for the presence of this potentially blinding illness.
“For me, it’s a precautionary measure,” she said. “Since both of my parents had glaucoma and required laser surgery to stabilize the disease, I try to have my eyes screened once a year.”
This month, David joined other residents at a glaucoma-detection booth at the annual Senior Fest health fair. Visitors peered into a noncontact tonometer, which blows a puff of compressed air into each eye to measure internal eye pressure.
Although Larry Metcalf, 60, took part in the health fair primarily to have his cholesterol evaluated, he didn’t hesitate to have his eyes screened for glaucoma.
“I try to have my eyes checked for glaucoma every year and a half just to play it safe,” he said. “My mother, who is 90, has glaucoma in one of her eyes. Since the doctors were able to catch it early on, it’s really not that serious.”
The booth was part of the mobile glaucoma-detection program. The Missouri Lions Eye Research Foundation sponsored the event.
Among the thousands of Missourians who have been tested through the program, 7 percent have exhibited heightened fluid pressure in their eyes. While this trait is commonly associated with glaucoma, eye pressure can be temporarily elevated through stress, excessive blinking or caffeine consumption. Nonetheless, those who test positive for this glaucoma-related symptom are advised to follow up with an ophthalmologist for an official diagnosis.
“As I understand it, (glaucoma is) something that becomes a greater matter for concern as we age,” David said. “I think that this sort of free screening is a real service to senior citizens.”
According to the National Glaucoma Research Foundation, glaucoma affects an estimated 2.2 million people nationwide, with 120,000 rendered permanently blind as a result of the condition. By 2020, glaucoma is expected to strike more than 3.3 million people in this country. An estimated 46,000 Missourians are afflicted.
“It is a very big problem, and it’s only going to get bigger over the course of time as the American population ages,” said Dan Schoenleber, a regional glaucoma specialist at the Mason Eye Institute. He said he treats an average of 40 new cases each month.
“The problem with glaucoma is that there typically aren’t any symptoms to speak of,” Schoenleber said. “By the time an individual realizes the loss, the vision that has been lost is irretrievable.”
Perhaps the most-heard myth in regard to a glaucoma diagnosis is that blindness is inevitable.
“One of the greatest universal misconceptions about glaucoma is that if you are diagnosed with it, it is only a matter of time before you go blind,” Schoenleber said. “Although you can’t really prevent glaucoma with treatment, through early detection it is usually possible to largely preserve the field of vision and allow the person to carry on a normal life.”
There are several methods available for treatment of glaucoma, including prescription medication, laser surgery and filtering microsurgery.
The most common type of the condition is known as primary open-angle glaucoma. It occurs in about 2 percent of the American population age 35 and older. For those 80 and older, the rate rises to one in 10. It is the chief cause of blindness among blacks.
“Primary open-angle glaucoma is a chronic disease and is hereditary,” Schoenleber said. “Frequency is high enough that most people know someone that might have it, though they may not be aware of it. I recommend that those with a family history of this form of glaucoma get their eyes checked at least once per year. Otherwise, it is encouraged that all individuals over 35 have their eyes screened at least once every two years.”
This form of glaucoma is especially difficult to detect because the unaffected eye can compensate for the other. Detailed central vision is not affected until later stages, and people generally assume that the reduction in vision is a byproduct of old age.
The Missouri Lions Eye Research Foundation will have its next screening from 7:30 to 11 a.m. Oct. 14 at the Factory Outlet Mall at Osage Beach. The entire screening calendar is available online at www.mlerf.org.