Early Tests Crucial For Glaucoma

Scientists have found that immediate treatment of newly-discovered primary open-angle glaucoma, the most common form of glaucoma and one of the nation's leading causes of vision loss, led to a slower rate of disease progression.

Dr. Norman Saffra, chairman of ophthalmology at Maimonides Hospital in New York, says on The Early Show that the findings from this study reinforce accumulating medical evidence that lowering eye pressure in glaucoma's early stages slows progression of the disease. The results are reported in the October 2002 issue of Archives of Ophthalmology.

The disease
Open-angle glaucoma affects about 2.2 million Americans age 40 and over; another two million may have the disease and don't know it. Glaucoma occurs when the optic nerve is damaged. In most cases, increased pressure in the eye is a risk factor for this damage. The damage to the optic nerve causes loss of peripheral (side) vision, although people are often unaware that they have glaucoma.

As the disease worsens, the field of vision gradually narrows and blindness can result. However, if detected early through a comprehensive eye exam, glaucoma can usually be controlled and serious vision loss prevented.

Glaucoma is one of the most common painless causes of blindness. It is a disease that develops without warning, and usually by the time a patient notices any vision loss the damage is already done. It is eight times more common in African-Americans. The diagnosis is made based on the "three-legged stool" of high pressure in the eye, peripheral vision changes, and optic nerve changes. No two patients have exactly the same combination of these characteristics.

One question has always been the value of treating high pressure in the eye if it is detected at an early stage before glaucoma has started to develop and before peripheral vision loss and optic nerve changes are apparent. The latest study addressed people whose pressures were a little high but everything else seemed normal to see whether treatment was effective.

Glaucoma is a long-term disease, and you can't tell by just one test at one point whether it's getting better or worse. The new study followed lots of patients for five years with an adequate ethnic balance.

Treatment
The study showed that treatment to reduce eye pressure with medication in eye drop form was effective in slowing the progression of glaucoma and had few side effects. Some of the older medications are not as safe, but if the new eye drops are not sufficient then the next step is laser surgery on the inside of the eye to reduce pressure, a simple outpatient procedure.

When To Be Tested
All adults should be tested for glaucoma every two years until age 64, then every year unless there's a family history of the disease, a racial predilection or an earlier exam showed suspicious results.

The Study
The study followed 255 patients, aged 50-80 years, with early stage glaucoma in at least one eye. The average age of the patients at the beginning of the study was 68 years. One group (129 patients) was treated immediately with medicines and laser to lower eye pressure, and the other group (126 patients) - the control group - was left untreated. Both groups were followed carefully and monitored every three months for early signs of advancing disease, using indicators that are extremely sensitive for detecting glaucoma progression. Any patient in the control group whose glaucoma progressed was immediately offered treatment. After six years of follow-up, scientists found that progression was less frequent in the treated group (45 percent) than in the control group (62 percent), and occurred significantly later in treated patients. Treatment effects were also evident in patients with different characteristics, such as age, initial eye pressure levels, and degree of glaucoma damage. In the treated group, eye pressure was lowered by an average of 25 percent.

There is still a lot we don't know about glaucoma, says Dr. Saffra. Although the study closely checked for possible glaucoma progression, many of the patients remained stable over time, even in the control group. On the other hand, despite the clear effect of treatment, glaucoma progressed in as many as 30 percent of treated patients after four years. The time it took for glaucoma to progress varied greatly among patients and was sometimes rather short, even in treated patients. This shows that in many patients with rapidly progressing glaucoma, the treatment used in this study was insufficient to halt progression of the disease.

The study authors say that treatment for early, newly diagnosed glaucoma should be individualized and carefully balanced. Before deciding on the best treatment option, eye-care professionals should consider several unique patient factors, such as age, eye-pressure levels, and disease severity. Although the study results confirm the belief that reducing eye pressure is beneficial, they do not prove that elevated eye pressure in itself is the primary cause of glaucoma.