Glaucoma develops when pressure builds in the eye and causes damage to the optic nerve, explains Louis Cantor, M.D., chairman of the Department of Ophthalmology at the Glick Eye Institute. “The optic nerve is the main cable carrying the messages from the eye to the brain. Damage to the optic nerve can cause blind spots to develop, and those spots often go unnoticed until they increase in size, impairing sight,” he said. “The result is vision loss that cannot be recovered.”
This week is World Glaucoma Week, dedicated to bringing awareness to the disease. The observance is to raise awareness of the disease, which can occur without symptoms in up to 50 percent of patients who have glaucoma. In the United States, more than 4 million people have glaucoma. African-Americans and Hispanics are more susceptible to the disease although it strikes all races. Risk factors for glaucoma include:
Being African-American or Hispanic
Having a family history of glaucoma
Having elevated eye pressure
Being farsighted or nearsighted
Having previous eye injuries
Having other health problems such as diabetes, low blood pressure or migraine headaches.
Working with Alon Harris, Ph.D., director of clinical research for the Glick Eye Institute, Dr. Cantor hopes their approach to understanding glaucoma will benefit patients in Indiana and around the world. “In Indiana alone, the number of patients with glaucoma could fill Lucas Oil Stadium,” he says. “And there are thousands more who have the disease who don’t know it, and they are most at risk for vision loss.”
Their study, the Indianapolis Glaucoma Progression Study, is the largest of its kind in the United States. With 120 patients enrolled for three years, the clinical trial is in its second year, and is focused on vascular – or blood flow – causes or effects of the disease. Dr. Harris is principal investigator of the study.
“I hope they learn something that can be applied to problems in the short run,” said patient Jim Palmer, an Indianapolis resident. “This study of blood flow might find out that it is just as significant as pressure, and that could be of benefit to all glaucoma patients.”
Dr. Harris explains that eye pressure is the most common measurement in glaucoma. But he notes that some patients develop glaucoma and don’t experience the high ocular pressure common in other patients, and some of those patients without high pressure lose sight to the disease. The research is important to determine if blood flow plays a part in the disease. Maybe, he said, some patients don’t receive enough blood flow to their eyes. This study will help determine if improper blood flow is a side effect of the disease or a cause of the disease.
“Unlocking the answer to that question could give us different treatment options for glaucoma,” Dr. Harris said. “Understanding the role the vascular system plays in the disease would bring a new way of looking at glaucoma patients.”
Dr. Harris is an international expert on the field of ocular blood flow and has designed and perfected many of the diagnostic tests performed on the study patients.
“I’ve learned a fair amount about this disease because of participating in the study,” Palmer said. “And they check so many different things that it would be cost-prohibitive to have all of this done if I did not participate in the study.”
Palmer, 67, has experienced glaucoma since about 1986. He learned he had the disease when he saw an ophthalmologist for a detached retina. He currently manages his glaucoma with drops he uses three times a day.
Study participant Carolyn Christman also is a long-time glaucoma patient. “I’ve learned the newest information from the doctors and the fellows and it’s been helpful to me to have this information about my glaucoma,” she said. The 70-year-old patient has had glaucoma since she was 42.
“This study, working on the relationship between blood pressure and blood vessels around the eye, is interesting to me,” she said. “Participating is my way of helping other people.”
The opportunity to participate in a study that could determine new treatments also appealed to Ronnie Adams. The retired 70-year-old African-American says glaucoma runs in his family – his father lost vision in one eye due to the disease and his sister, who also has glaucoma, convinced him to have his eyes examined.
“I’d say the study experience has been really good,” Adams said. “I don’t want to lose my eyesight and right now it looks as if the drops I use are helping. It’s important to try to do something to improve the situation or not lose vision.”
Cantor and Harris say the participation of their study patients is crucial to their success in formulating new discoveries about glaucoma.
“We rely on our patients to help us understand why this disease strikes when it does,” Cantor said. “We’re interested in learning if the blood flow theory is one we could explore further and we need our study patients to help us.”
Glaucoma is not the only disease that causes vision loss – but vision loss from many conditions can be prevented with proper care. Most people begin to experience changes in their vision as they turn 40, Dr. Cantor said. By age 65, one in three Americans will experience some form of vision-impairing eye disease.