December 1, 2005 Building upon a recent discovery that the same Alzheimer's disease process that goes on in the brain also occurs in the eye, researchers have developed a pair of optical tests that can determine the presence of amyloid beta proteins -- found in all Alzheimer's patients -- in the lens of the eye. A device called an interior laser ophthalmoscope can pick up the presence of the amyloid protein.
BOSTON -- Since 1980 the number of Americans with Alzheimer's has nearly doubled to 4.5 million. The disease robs people of their memory, while early detection of Alzheimer's has eluded members of the medical field for years. Now a new eye test may help determine if you're at risk and may unlock that mystery.
They say the eyes are the windows to the soul, now they may be the key to saving some people's lives. A new eye test may help in the early detection of Alzheimer's. Dr .Lee Goldstein, a psychiatrist in the Dept. of Psychiatry and Surgery at Brigham and Women's Hospital in Boston, says, "We found the Alzheimer disease process that goes on in the brain also occurs in the lens of the eye."
Dr. Goldstein developed a pair of optical tests that can determine the presence of amyloid beta proteins in the eye lens -- a protein prevalent in the brain of all Alzheimer's patients. The interior laser ophthalmoscope can pick up the presence of the amyloid protein. "What this instrument is capable of doing is picking up those gummy aggregated particles in the lens very early, before you see the cataracts," he says.
The cataract looks like a cloudy arc on the rim of the lens. This is different than the common cataract. To determine if this is an Alzheimer's cataract, Dr. Goldstein injects the eye with special fluorescence drops that bind to the amyloid beta proteins. Under an infrared light, the proteins will glow, indicating Alzheimer's disease.
"If we can get treatments early ... we can slow the disease to the point where we've effectively cured it," Goldstein says. That extra time could give Alzheimer's patients more precious time to live.
This eye test may not only improve patients' chances to start treatment earlier, but it could also speed development of new Alzheimer's drugs.
BACKGROUND: Researchers at Harvard Medical School have developed two optical tests that could potentially diagnose Alzheimer's disease in its beginning stages. The tests build upon a recent discovery that the presence of telltale proteins in the eye is an early sign of the disease. Such tests can improve patients' chances to start treatment earlier, and may also speed development of new drugs.
HOW IT WORKS: The same type of amyloid beta proteins which are a hallmark of Alzheimer's when found in the brain are also found in the lens and fluid of the eye. These proteins produce an unusual type of cataract in a different part of the eye than common cataracts (which are not associated with Alzheimer's). Scientists can detect these proteins by injecting a light-sensitive dye, then shining a laser onto the specific part of the lens where the cataracts tend to form. The molecules in the dye bind to the protein molecules, if they are present, and the light will cause the resulting molecules to glow. This technique is called quasi-elastic light scattering.
SYMPTOMS: Alzheimer's is a slow-moving disease, and in its earliest stages, may merely appear to be mild forgetfulness, and confused with age-related memory change. There may be problems remembering recent events or activities, or the names of familiar people or objects. As the disease progresses, the forgetfulness becomes more severe, interfering with daily activities, such as brushing one's teeth. There are problems speaking, understanding, reading or writing, and eventually the brain damage becomes so severe as to require total care.
FACTOID: As many as 4.5 million Americans suffer from Alzheimer's disease. It usually sets in after age 60, and the risk increases with age, although it is not a normal part of the aging process. While only about 5 percent of men and women aged 65-74 have the disease, nearly half of those 85 or older may have it.
The Optical Society of America contributed to the information contained in the TV portion of this report.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.