Sep 14 2004
A new approach for assessing glaucoma risk factors could be the first step in helping ophthalmologists determine the risk of progression from ocular hypertension to glaucoma and blindness, according to an article published today in the September issue of the American Journal of Ophthalmology.
This new approach, which is based on the risk assessment principles advanced by the coronary heart disease model, could help physicians decide the level of risk in an individual patient and whether to begin treatment in order to prevent glaucoma onset and irreversible damage.
The approach is the focus of a multi-year continuing medical education (CME) initiative on "Treatment of Risk in the Glaucoma Continuum" jointly sponsored by the University of Medicine and Dentistry of New Jersey (UMDNJ)-New Jersey Medical School's Institute of Ophthalmology and Visual Science, the UMDNJ-Center for Continuing and Outreach Education, and Medical Intervention Systems (MIS).
Glaucoma is a neurodegenerative disease that damages the optic nerve and can lead to blindness if left untreated. Because the disease has no symptoms, by the time it is detected, a patient already may have irreversible damage that can lead to vision loss. The risk factors for glaucoma include age, African American or Hispanic origin, family history, diabetes, hypertension, nearsightedness, trauma or injury to the eye, a thin cornea, or elevated pressure in the eye.
Glaucoma disease has several stages, beginning with people "suspected of having glaucoma." An individual in this category has one or more risk factors – such as ocular hypertension or high intraocular pressure (IOP) – but optic nerve changes are still undetectable. Patients in the next stage of the disease are "diagnosed with having glaucoma" because changes in the retinal nerve fiber or optic disc and visual function can be detected.
"Most clinicians recommend treatment once damage to the optic nerve head is detected or when IOP is high," said Robert D. Fechtner, MD, course director of the "Treatment of Risk in the Glaucoma Continuum" initiative, and professor of ophthalmology at the Institute of Ophthalmology and Visual Science at UMDNJ-New Jersey Medical School. "Although high IOP is clearly a risk factor, we know other factors also must be involved because even people with 'normal' IOP can experience vision loss from glaucoma. This new approach should help us more clearly assess who is at risk, whom to treat and when to treat," said Fechtner.
The assessment of scientific risk for developing glaucoma was patterned on the model that has been used for many years in managing patients with cardiovascular disease. The heart study risk model is based on data from studies that identified key predictive risk factors for cardiovascular events, including the landmark, decades-long Framingham Heart Study.
"Global risk assessment in coronary heart disease provides an example of how the ability to detect and treat underlying factors can mark significant strides in the way a disease is managed," said AJO Perspectives article co-author William B. Kannel, MD, MPH, professor of medicine and public health at Boston University School of Medicine and senior investigator and director of the Visiting Scientist Program at the Framingham Heart Study. "Before Framingham, most physicians didn't aggressively manage predisposing cholesterol levels or high blood pressure; they treated patients who had already suffered heart attacks or strokes. We hope that this glaucoma initiative and subsequent research will effect the same kind of shift toward prevention and earlier intervention for those at risk versus intervention at a later stage in the disease."
"This approach is a step forward in developing a scientific basis for deciding whether to treat a specific individual or not," said Robert N. Weinreb, MD, lead author of the AJO Perspectives article and program chair of the "Treatment of Risk in the Glaucoma Continuum" initiative. "In many respects clinical research in glaucoma faces the same challenges today that cardiovascular disease research faced 20 years ago. This approach has the potential to have the same impact for glaucoma as the Framingham Study had on cardiovascular medicine." Dr. Weinreb is the Director of the Hamilton Glaucoma Center and Professor of Ophthalmology at the University of California, San Diego.
Glaucoma affects approximately 3 million people in the U.S. and 67 million people worldwide. It is the second leading cause of blindness in the U.S. and the leading cause of preventable blindness. An estimated 120,000 Americans are blind from glaucoma, accounting for 9 percent to 12 percent of all cases of blindness in the U.S.