August 07, 2013
1 min read

Early Alzheimer’s detection may be possible through the eye

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Noninvasive diagnostic retinal testing could possibly hold the answer to early Alzheimer’s disease detection and treatment. The PRIMARY CARE OPTOMETRY NEWS August cover story details how retinal testing may detect amyloid beta protein deposits, the biomarker of Alzheimer’s disease.

Neurologists have theorized a correlation between the amount of amyloid in the eye and amyloid in the brain. If correct, the retina could be the solution to early detection and treatment of Alzheimer’s disease (AD), as amyloid beta protein accumulation may begin approximately 20 years prior to memory loss symptoms. To confirm this theory, two tests have been developed: the Retinal Amyloid Index by NeuroVision and the Sapphire II by Cognoptix.

“Ocular exams through the years have attempted to diagnose Alzheimer’s at an early age,” Michael Tolentino, MD, PRIMARY CARE OPTOMETRY NEWS Editorial Board member, said. “We have looked at optic nerve cupping, pupillary response to tropicamide dilation and ocular muscle movement. While all have been investigated, all have failed to withstand the test of time in terms of sensitivity and specificity, and all were subjective in nature. Cognoptix and NeuroVision are trying to objectify the diagnosis.”

The ability of the Sapphire II and Retinal Amyloid Index to easily qualify patients for clinical study inclusion will give pharmaceutical companies a foundation to identify product performance in phase 4 studies, and therefore mark clinical effectiveness to detect and treat AD in a reliable way.

“Most people, if they’re going to get AD, start developing the pathology hallmarks, such as amyloid deposits, in their 50s,” Keith L. Black, MD, chairman and professor of the Department of Neurosurgery at Cedars-Sinai Medical Center in Los Angeles, and cofounder of NeuroVision, said. “The key for having an effective treatment for AD is early detection. You want to prevent those brain cells from being killed or dying in the first place.”

“The amount of photons captured is a direct correlation with the amount of amyloid in the lens of the eye,” Carl Sadowsky, MD, medical director of the Premiere Research Institute at Palm Beach Neurology in West Palm Beach, Fla., said. He stated that the Sapphire II is currently in phase 1/2 of clinical feasibility trials and that phase 3 is expected to begin in 2014.