A new study, published Acta Neuropathologica, is helping researchers understand the complex relationship between Alzheimer’s disease and the retina, particularly in the earliest stages of cognitive decline.
What is Alzheimer’s disease?
Alzheimer’s is the most common type of dementia, and it impairs thinking, behavior and memory. Over time, symptoms of Alzheimer’s will make daily tasks more difficult. About 60 to 80 percent of people with dementia have Alzheimer’s, and doctors diagnose about three million new cases of Alzheimer’s each year. There is no single test that can diagnose the disease, and there is no cure. The newest and most advanced treatments only slow its progression.
Alzheimer’s and its effects on the brain
Alzheimer’s prevents nerve cells, or neurons, in the brain from functioning efficiently. Scientists aren’t sure how the process begins, but two anomalous structures called plaques and tangles begin damaging and killing neurons. Plaques are a buildup of proteins called beta-amyloid that accumulate in the space between nerve cells and interrupt cell communication. Tangles are twisted fibers of a different type of protein that also collect inside neurons.
Link between Alzheimer’s disease and retinal health
Researchers from Cedars-Sinai Hospital wanted to learn more about the connection between the brain and the retina in patients with Alzheimer’s. The team examined retina and brain tissue samples from 86 donors with confirmed Alzheimer’s disease and mild cognitive impairment. They compared those samples with samples from donors with normal brain function and those with advanced Alzheimer’s disease.
The research team analyzed the patients’ retinas and brain tissue and found an excess of a protein called amyloid beta 42 that disrupted brain function. They also found an accumulation of amyloid beta protein in ganglion cells, which are responsible for transmitting information between the retina and the optic nerve.
“The retina, a developmental extension of the brain, offers an unparalleled opportunity for affordable, noninvasive monitoring of the central nervous system,” said Yosef Koronyo, MSc, research associate in the Cedars-Sinai Department of Neurosurgery and first author of the study. “And with the help of our collaborators, we discovered the accumulation of highly toxic proteins in the retinas of patients with Alzheimer’s disease and mild cognitive impairment, causing severe degeneration of cells.”
The researchers hope that learning more about the brain and retina in patients with Alzheimer’s may lead to a clear diagnostic for Alzheimer’s as well as effective treatments.
Schedule an eye exam during Healthy Vision Month
Did you know that May is Healthy Vision Month? The National Eye Institute and Centers for Disease Control encourage all Americans to prioritize healthy vision and get an annual comprehensive eye exam with dilation.
Your ophthalmologist can detect refractive errors like nearsightedness or presbyopia, a condition that makes it difficult to see things up close. Eye exams also include screenings for common eye conditions like cataracts, glaucoma, diabetic retinopathy or age-related macular degeneration.
Celebrate Healthy Vision Month by calling your eye doctor to make an appointment for a comprehensive eye exam. It takes less than an hour, but it provides a lifetime of benefits — clear, healthy eyesight!