Alzheimer’s and the Eyes: Connections, Early Detection and More

Recent studies and research strongly link eye health to various conditions, including Alzheimer’s. The eyes are essentially an extension of the brain, and because Alzheimer’s affects the brain and its cognitive functions, specialized eye exams can help reveal warning signs of the disease.

Intro

Advancements in technology and more research into the causes and effects of Alzheimer’s disease have led to the realization that refined eye examinations can be an important diagnostic tool.

Alzheimer’s Disease causes a progressive deterioration of brain cells and function. Some signs of this deterioration may be shown in the eyes, making certain screening techniques a useful early indicator.

Early detection can have a dramatic impact in slowing the progression of Alzheimer’s.

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What Is Alzheimer’s Disease?

Alzheimer’s disease is a progressive neurodegenerative condition and is the most common type of dementia. Since this is a progressive disease, the initial symptoms might include mild memory loss. However, with time, the disease develops and can lead to a decline in mental functions and interfere with your ability to remember, think, and even speak.

Managing and treating Alzheimer’s disease once it’s progressed beyond a certain threshold is costly, and results aren’t a guarantee. As such, early detection is the best way to deal with the disease. Unfortunately, Alzheimer’s diagnosis tests are invasive, expensive, and hard to acquire.

Fortunately, according to a 2019 Ophthalmology Retina study, doctors can employ certain eye exams to detect and diagnose the disease early on. This study, conducted by the Duke Eye Center, is non-invasive and reveals the results in seconds.

How Are Eyes Linked to Alzheimer’s?

In the 2019 study, researchers found changes in the appearance of retinal blood vessels in Alzheimer’s patients. Changes were evident in patients who were in an early stage of the condition.

In general, there’s a direct link between the eyes and various cardiovascular illnesses. In the future, some of these diseases can be diagnosed early, adequately managed, cured, and prevented in some cases. Some of the eye conditions linked with cardiovascular conditions include:

• Diabetic retinopathy is common in diabetic patients and occurs when high blood sugar levels damage retinal blood vessels.
• Glaucoma has been linked to conditions like diabetes, high blood pressure, and poor blood circulation.
• Age-related macular degeneration is linked to heart disease and related complications.

Researchers believe there is a direct relationship between Alzheimer’s disease and eye conditions like glaucoma, diabetic retinopathy and macular degeneration. They have hope that understanding how these eye diseases impact your cardiovascular and overall health could prove helpful in combating them. In recent times, there have been more studies seeking to understand this relationship.

Can Your Eyes Help Detect Alzheimer’s?        

Alzheimer’s is a complex disease all from start to finish – from diagnosis to treatment to management to conclusion. Diagnosing the disease, especially in the early stages, has proven difficult. While there are existing techniques used to diagnose the progressive condition, most are impractical for mass use.

Doctors can use brain scans, for example, to diagnose Alzheimer’s. However, the scans are expensive and not easily accessible. Spinal taps are another option, but these tests are painful to the recipient and potentially dangerous.

Today, behavioral abnormalities and memory tests are the most-used ways to identify if someone has Alzheimer’s. Unfortunately, by the time notable change is observed through these methods, the disease has already progressed.

An eye test is not only simple, easily accessible and non-invasive, it also is an effective way to diagnose the condition. The change in retinal blood vessels can be detected early enough to start remedial procedures to slow the disease’s progression.

The Duke Eye Center study suggests using the eye test to differentiate between patients with mild cognitive impairment and those with Alzheimer’s disease. While this is the most extensive study so far, the results are promising, and more research into the area could help with better diagnosis, management, treatment and prevention options.

How Retinal Scans Diagnose Alzheimer’s

Doctors use a retinal scan to detect the disease. This biometric testing technique detects specific patterns on the retinal blood vessels.

Essentially, retinal imaging works like a digital picture that shows the optic disk, retina and blood vessels. The test is used by ophthalmologists and optometrists to detect certain diseases and check your eyes’ health.

When detecting Alzheimer’s, professionals use an optical coherence tomography angiography (OCTA) test. This is a state-of-the-art, precise, and non-invasive imaging technique that shows even the tiniest blood vessels at the back of the eyes. Some of these blood vessels are thinner than a strand of hair, so precision is critical when studying them.

According to the study’s researchers, the retina is an extension of the brain. As such, there are various similarities between the eye and the brain. Deterioration of the retina can therefore be likened to changes in blood vessels in the brain.

How Does Alzheimer’s Affect Your Eyes?

Like other dementia conditions, Alzheimer’s can damage the visual-perception system in various ways. The change and damage can differ depending on the type of dementia condition and its progression stage. Among the ways Alzheimer’s affects your eyes:

• Poor color discrimination
• Problems with object recognition
• Loss of depth perception
• Decreased peripheral vision

Poor Color Discrimination

Dementia patients can face challenges distinguishing among colors. Alzheimer’s patients have a hard time recognizing colors in the blue to the violet range.

Problems with Object Recognition

While the eyes could still see an object clearly, the brain could misinterpret the object in patients with Alzheimer’s disease.

Loss of Depth Perception

Alzheimer’s patients may find it hard to differentiate flat pictures from three-dimensional objects as the disease progresses. This could also develop further to a point where the patient can’t correctly judge distances.

Decreased Peripheral Vision

Dementia patients also suffer from a lack of peripheral vision. In some cases, the patient can’t see objects to their side and have trouble walking without tripping.

References

1. Early Detection of Disease and Scheduling of Screening Examinations. (December 2004). National Center for Biotechnology Information.

2. What is Alzheimer’s disease? (January 2019) The Alzheimer’s Association.

3. Alzheimer’s Disease Clinical Trials Success Rate Globally From 2008-2019, by Phase. (July 2019) Statistica.

4. Retinal Microvascular and Neurodegenerative Changes in Alzheimer’s Disease and Mild Cognitive Impairment Compared with Control Participants. (June 2019). Ophthalmology Retina.

5. Alzheimer’s Disease, Dementia and the Eye. (May 2019). American Academy of Ophthalmology.

6. Dementia, Alzheimer’s and Change in Perception. (January 2021). Alzheimer’s Society.