Durham, N.C. -- Treatments that delay the progression of glaucoma may significantly reduce the economic health burden on people with the disease and on the U.S. health system, according to a new study by researchers at and elsewhere. Their findings appear in the January 9, 2006, issue of .

The team determined that patients with early-stage or suspected glaucoma use approximately $623 per year in health care resources, while patients with end-stage disease consume approximately $2,511. The cost of medication was responsible for one-third to half of the total direct cost to consumers.

"It is imperative that patients with glaucoma be well-monitored for changes in their disease," said Paul Lee, M.D., a glaucoma specialist at Duke Eye Center and lead author on the study. "Our results prove what we've thought for a long time –that the disease gets more expensive as it worsens. With effective treatments at earlier stages, the progression of disease can be slowed or halted –saving both the patient and society from greater economic burden."

Glaucoma is a leading cause of blindness in the U.S., affecting an estimated 2.2 million adults, the researchers said. Experts anticipate the overall number of people living with glaucoma to rise as the number of elderly Americans increases. Glaucoma is a group of eye diseases that damage the cells and fibers of the optic nerve, interrupting the transmission of visual signals from the eye to the brain. The disease is believed to be caused by a level of intraocular pressure (IOP) that is too high, although other mechanisms are likely to be involved since people can develop the disease and have a normal IOP. Many people go undiagnosed during early stages of the disease because symptoms are virtually undetectable without an eye exam.

In their study, the team sought to determine whether the costs of managing glaucoma varied as the disease progressed in order to understand the relationship of patients' use of health resources to the severity of their disease.

They analyzed 151 randomly selected records of adult patients (average age was 66.3 years) with different severities of primary open-angle or normal tension glaucoma, as well as those suspected of having either glaucoma or ocular hypertension. They obtained records from 12 study sites throughout the U.S.

The researchers categorized patient records according to the severity of the patients' glaucoma. For each stage of severity, the researchers obtained economic data on the cost of the patients' use of eye care visits, visual field and other diagnostic testing, treatment procedures, low vision and other rehabilitation services, and prescribed medications. While the researchers based the medication costs used in the study on wholesale prices, they said actual costs might be higher because consumers typically pay more than the wholesale cost.

"We know that for chronic diseases such as glaucoma, people don't use their medications as frequently as recommended by their physician," said Lee. "We took this into account in our study, but we suspect that the true costs of medication use could be even greater than we found."

The researchers found that aggressiveness of glaucoma treatment increased over time with worsening of the disease, except for patients with end-stage glaucoma. That aggressiveness is likely to drop off in patients who have gone blind from glaucoma because treatment options for those patients may not offer significant benefits, said Lee.

"Since our data were collected, additional treatments have become available," Lee added. "However, these medications are fairly expensive. Ultimately, it may cost patients and society more to care for patients in earlier stages of the disease –but over the long-term, when managed correctly and effectively, glaucoma patients can retain more of their vision and therefore remain more productive with a presumably higher quality of life."

The research was funded by an unrestricted grant from Allergan, Inc., Irvine, CA.

Other authors on the study include John G. Walt, Allergan; John J. Doyle, Sameer V. Kotak and Stacy J. Evans, M.D., of The Analytica Group, New York; Donald L. Budenz, M.D., University of Miami; Philip P. Chen, M.D., University of Washington, Seattle; Anne L. Coleman, M.D., Ph.D., Jules Stein Eye Institute, UCLA, Los Angeles; Robert M. Feldman, M.D., University of Texas, Houston; Henry D. Jampel, M.D., Johns Hopkins University, Baltimore, MD; L. Jay Katz, M.D. and Johnathan S. Myers, M.D., of Wills Eye Hospital, Philadelphia; Richard P. Mills, M.D., University of Kentucky, Lexington, KY; Robert J. Noecker, M.D., University of Arizona, Tucson, AZ; Jody R. Piltz-Seymour, M.D., University of Pennsylvania Health System, Philadelphia; Robert R. Ritch, M.D., New York Eye & Ear Infirmary, New York; Paul N. Schacknow, M.D., Ph.D., Palm Beach Eye Foundation, Lake Worth, FL; Janet B. Serle, M.D., Mount Sinai School of Medicine, New York; and Gary L. Trick, Ph.D., Henry Ford Health System, Detroit, MI.