Federal health officials, alarmed by the increasing number of cases of debilitating eye disease, are advocating a regular schedule of eye exams that include dilation of the pupils.
The National Eye Institute in December issued a sweeping new set of recommendations that call for regular, extensive eye exams in black Americans over the age of 40, in all Americans 60 years and older and in people with diabetes.
The recommendations are designed to detect two very common and very damaging eye diseases: diabetic retinopathy and glaucoma. Both are best detected by an eye exam that dilates the pupils. In the case of glaucoma, dilation is more effective than the quicker and less expensive pressure test.
Often, screenings for glaucoma have relied on the pressure test, in which an instrument is placed on the surface of the eye to measure the pressure of fluid. This is used commonly at community-wide screenings, and sometimes at optometrists' offices and quick eyeglass retail stores.
"Millions of people could be saved from vision loss, even blindness, by following these recommendations," said Public Health Service head James Mason in announcing the new guidelines.
With the aging of the population, vision loss is becoming a major public-health problem. Diabetic retinopathy strikes up to 7-million people annually, according to the NEI. Of this group, roughly 700,000 people have serious retinal disease and an estimated 8,000 people go blind from the disorder, making it one of the leading causes of vision loss.
Diabetic retinopathy slowly damages the delicate blood vessels of the retina, the membrane at the back of the eye that contains light-sensitive nerve cells that transmit images to the brain. Symptoms occur so gradually that they may not be noticed until vision is permanently impaired.
An additional 3-million Americans suffer from glaucoma, the leading cause of blindness in older adults and in blacks over age 40. The condition elevates fluid pressure within the eye. Over a period of years, the optic nerve is damaged and vision slowly erodes.
A study published in November in the New England Journal of Medicine by researchers at the Johns Hopkins Medical Institutions found that roughly half of people afflicted with glaucoma go undiagnosed until vision is permanently damaged. Estimates are that 120,000 Americans are now blind from the disease.
Glaucoma costs an estimated $1.5-billion annually in health-care expenditures, Social Security benefits and lost wages, according to the NEI. The new recommendations are designed to improve early detection with the use of pupil dilation.
A survey of 1,250 adults conducted last year by the National Eye Institute and the Lions Clubs International found that 75 percent of high-risk participants for glaucoma had received eye exams during the past year. But fewer than half of them had their pupils dilated as part of the exam.
"What we would like to get across is that screening exams that have been used for many, many years to detect glaucoma are inadequate in many patients," said Claude Cowan, chief of the division of ophthalmology at Howard University Hospital, who kicked off the program by examining the eyes of Health and Human Services Secretary Louis Sullivan.
Most screening exams solely test eye pressure, a measure that may give a false sense of security. Studies show that roughly one-third of patients with glaucoma have eye pressure that fluctuates and can often appear normal.
"If you rely on eye pressure alone (to detect glaucoma), you will miss these patients," Cowan said. Pupil dilation is also needed to detect a small percentage of patients who have normal eye pressure but are in a pre-glaucoma stage, he said.
The exam also is essential for diagnosing the tiny vascular changes that occur in diabetic retinopathy. The exam can be performed either by an ophthalmologist _ a physician specializing in the eyes _ or by an optometrist _ an eye professional trained to fit prescription glasses.
Pupil dilation consists of putting a few drops of medicine in the eyes. This enlarges the pupil within 15 to 20 minutes and allows the eye examiner to look at the back of the eye for early signs of disease.
For further information, contact the National Eye Health Education Program, Box 2020, Bethesda, Md. 20892.
Who should get regular eye exams
Among those targeted by the National Eye Institute for regular eye exams that include pupil dilation are:
The 14-million diabetics who run an increased risk of eye problems. Roughly half will develop eye problems, Public Health Service head James Mason said, ranging from cataracts _ the formation of opaque scar tissue on the corneas _ to diabetic retinopathy. Diabetics also face twice the risk of developing glaucoma as other adults. The NEI recommended that these individuals undergo annual eye exams.
Americans age 60 and older, who run an increased risk of glaucoma. Roughly half of those with glaucoma have no idea that they are afflicted because the early stages of the disease show no symptoms. People in this group should undergo eye exams with pupil dilation every two years.
Black Americans, ages 40 and older, who face five times the risk of developing glaucoma as whites and are four times more likely than whites to become blind from the disease, according to the Public Health Service. Blacks should undergo an eye exam, including pupil dilation, every two years, according to the NEI.