How Alzheimer’s Disease Impacts Vision


People with some form of dementia, especially Alzheimer's, can experience vision impairment, leading them to have difficulties with perception, thus misinterpreting the world. The changes in vision can further cause behavioral and safety challenges. Families who understand these changes can be able to better support their loved ones and modify their living environment so their loved ones won't have to leave the home to receive quality home care. Anchorage Alzheimer's care professionals highlight some aspects of Alzheimer's disease and its impact in vision.
How Alzheimer’s Disease Impacts Vision

Collective Functions of the Brain and Eyes

Since Alzheimer's disease related to the brain and vision changes are common among seniors, a range of visual errors can take place.


Considering the basics of the visual process of the body

1.    The information is transmitted to the brain from the eyes for interpretation.
2.    Other senses, memories, and thoughts also contribute their share of information that influences the current interpretation.

3.    Then you get aware of what you have seen, which forms a perception.
These visuoperceptions can be incomplete or imprecise due to the impaired functions of the diseased areas of the eyes and brain, leading the person with Alzheimer's to distress, as well as his or her caregivers and family members.

The Job of Beta Amyloid in Alzheimer's and Vision Loss

Beta Amyloid is a protein which is broken down and eliminated in a healthy brain. However, it accumulates in a hard, insoluble form called plaques leading to Alzheimer's.

The protein, beta amyloid plays a crucial role in both conditions, relating them to each other as well. A hallmark of Alzheimer's disease is the accumulation of beta amyloid in the brain. Further formation of plaque in the brain leads to chronic cognitive and social decline. Beta amyloid, according to different studies, has been also linked to neurodegeneration in the retina. The buildup of plaque on retina causes age-related macular degeneration, the major cause of vision loss among seniors.

Multiple research now associate the plaque with the primary stages of age-related macular degeneration, as it validates the buildup of the toxic agent that targets the cells in the degenerative brains or those with Alzheimer's. By analyzing the accumulation of plaque in the eye, it may be easy to predict much larger accumulation in the brain.


Common Defects in the Vision

In Alzheimer's, the following are the five major visual defects.

1. Deteriorated Motion Detection

As the Alzheimer's affects vision, the influenced person becomes unable to detect movement. This can cause people with Alzheimer's to wander or even become lost, even in known surroundings. Following a motion or a moving objects become challenging and affects the ability to easily watch a movie or do anything including fast movement.

2. Lowered Peripheral Vision

The field of vision gets narrow as people age, but for those with Alzheimer's, the narrowing of vision occurs dramatically. They may find themselves unable to see to either side when focusing forward, which leads to disorientation and increases the risk of bumping into things. They may also startle when someone is approaching them or when they have to suddenly turn to miss a wall or a stone.

3. Color Perception

Colors often diminish as a person gets older, but in case of Alzheimer's, there is a greater deficit and the affected person can face challenges in recognizing colors, particularly the blue-violet range. This can also cause issues in clothing coordination.

4. Depth Perception

With Alzheimer's, people can lose their perception for depth. They face challenges at changes in elevations, judging distances or differentiate between a three-dimensional item and a flat or two-dimensional picture. For example, they may want to pick up flowers in a floral print or painting or try to step up when they see a border or square prints on a carpet as it if it were stairs.

5. Contrast Sensitivity

Just like colors, the ability to detect gradients of colors also deteriorates in people with Alzheimer's. They will think that different shapes printed on a floor or a fabric are actual objects. They will also have difficulty identifying objects surrounded by similar colors. For example, a person with vision impairment and Alzheimer's will have difficulty finding the toilet in a bathroom where everything; walls, floor, and toilet, is white or of the same color.

Deteriorated Facial and Object Recognition

People with Alzheimer's and related vision impairment can face difficulties in recognizing objects and even faces when someone they know or who knows them tries to approach them. They even experience the inability to name what they see.

Common Visual Perception Challenges


1. Illusions

Illusions are a distortion of reality. This happens from the characteristics of an object. A person with Alzheimer's will perceive a sparkling tile floor or shiny sheet as wet.

2. Misidentifications

The affected parts of the brain by Alzheimer's can lead to identifying people and objects. For instance, differentiating between a sister, mother, or wife may get difficult, and even, a green ball may seem like a broccoli.

3. Misperceptions

What the eyes see is the best guess at the distorted or inaccurate information the eyes transmit to the brain. This is caused by the damaged visual system by illnesses like glaucoma or cataracts. For example, reflection in a mirror can be mistaken for an intruder or a shadow on the floor can be misinterpreted from a hole on the floor.

4. Hallucinations & Delusions

These visual perception changes can very easily affect a person’s daily life, including reading, watching TV, and writing, using the bathroom, and moving around the home. It can also lead the person to do or say strange things which make other people think of delusions. However, in reality, these are not delusions. Delusions base on incorrect reasoning. In fact, these issues are a result of damages visual process which involves the brain and eyes.

In terms of delusions or hallucinations, they are different from the visual perception mistakes.

Hallucinations involve seeing or thinking of something that is not actually happening. They are sensory experiences that include imagination.

Unlike hallucinations, delusions incorporate a set of false belief. For example, as a person with Alzheimer’s has delusions, he or she will become suspicious for the people around them. The person will believe that the family members or caregivers are trying to steal his or her clothes when, in reality, they are just taking the clothes to wash them. It is based on wrong reasoning, also known as delusional thinking. Cognitive decline and memory loss cause confusion and contribute to such irrational beliefs.

It is important to remain calm and consistent when your loved one experiencing an event of hallucinations, and avoid telling your loved one that he or she is wrong. Instead, assure your loved one that you believe in him or her and provide help to calm down the situation.

Bottom Line

As Alzheimer's is a disease of the brain and it can also relate to vision loss, both conditions can work together and lead to difficulties like confusion, improper reasoning and judgment, and irrational beliefs. This is mainly because of the cognitive decline functioning with loss of vision.

Don’t forget to speak with a medical specialist about your loved one’s condition and ask for prescription medications to manage the symptoms. Since the disease is chronic, it cannot be reversed but effective medications and therapies can slow its progression.

Author Bio

Edward Lee has been writing articles since her teenage and is currently enjoying a successful career as a content writer. She loves to write about helping and motivating others to find a way to happiness and working everything out despite the challenges of life. This is the reason she has chosen home care industry and is currently employed with Home Care Assistance of Anchorage.
How Alzheimer’s Disease Impacts Vision How Alzheimer’s Disease Impacts Vision Reviewed by Chibuzor Aguwa on Saturday, December 22, 2018 Rating: 5

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