Early detection of Alzheimer’s disease

Could be done with noninvasive optical methods. Two years ago, researchers discovered that the exact same β-amyloid peptides (Aβ) that are a hallmark of Alzheimer’s disease also appear in the eye’s lens and its surrounding fluid. Where those proteins collect in the eye, they form amyloid deposits similar to those in the brain. The researchers also discovered that Aβ in the lens produces a very unusual cataract, formed in a different place than common cataracts (which are not at all associated with Alzheimer’s). The next step was revealed in October, at the Frontiers in Optics meeting of the Optical Society of America in Tucson, Arizona. Lee Goldstein, who is leading the research at Brigham and Women’s Hospital in Boston, presented a pair of optical tests that can noninvasively detect Aβ in the lens. Using quasi-elastic light scattering, the first test—now in clinical trials—employs low-power IR laser light to detect proteins in the lens’s supranucleus, the part uniquely susceptible to the unusual Alzheimer’s cataracts. The second, complementary test—now in advanced development—uses a technique Goldstein and colleagues call “fluorescence ligand scanning.” In FLS, special eye drops contain molecules that bind specifically to Aβ and then fluoresce. Such tests may not only improve patients’ chances to start treatment earlier, but could also speed development of new Alzheimer’s drugs.