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Chapter 1

How Vision Changes with Dementia


The vision changes from dementia cause confusion and fear. You might notice strange behaviors and responses. Many people mistakenly think the odd behavior is a result of hallucinations. Understanding the changes helps you provide more compassionate care.

5 Ways Vision Changes With Dementia

1. Blurring

Blurring is when one sees things less sharply. Faces and common objects can become harder to recognize. Blurring can cause confusion and difficulty finding objects. Another challenge is not being able to read or write.

Caregiver tips:

  • Make it clear who you are when interacting with a person with dementia. For example, don’t say “it’s me.” Instead say “Hi Mom, it’s Bob, your son.”
  • When you give your care partner an object, state what it is. Such as “here is your hairbrush.”

2. Pupils reacting slowly to light

Slow reactions to light make it hard to go from a light space to a dark space. When a person with dementia turns from looking out a bright window the room will appear dark. Going outside on a sunny day can be overwhelming. The light appears too bright until the pupils react.

Caregiver tips:

  • Allow plenty of time to adjust to different levels of light.
  • When waking up in the morning, keep the lights low. Turn on a small light first.
  • Go slowly when entering from outside. Wait patiently inside the door until their eyes adjust.
  • Encourage your care partner to shield their eyes from the sun, and wear a wide brimmed hat or sunglasses outside.
  • Reduce glare and shadows in the house with blinds and adequate lighting.

3. Smaller visual field

Your visual field is the area around you in which you can see things. Dementia causes this field to become smaller. With dementia the visual field can narrow to only 12 inches. Teepa Snow, a dementia educator, describes this smaller visual field as "like trying to move around while wearing binoculars."

This means that when a person with dementia is moving around they see much less than you do. A bathroom door in “plain sight” might not be seen. It is normal to have a smaller visual field as you age. But with dementia, the visual field is much smaller.

Caregiver tips:

  • You can use large pictures to help a loved one with dementia find common things. A large picture that is easy to see can help identify where to find a mug.
  • Another idea is to use bright colors. Contrasting colors are easier to see. A bright colored plate on a light-colored table will be more noticeable. Contrasting colors make it easier to see the food as well.

4. Loss of peripheral vision

Peripheral vision is when you can see things that are not directly in front of you. You see things “out of the corner of your eye.” A loss in peripheral vision causes difficulty seeing objects around you. This vision loss can lead to falls, tripping over chairs, or bumping into door frames.

A person with dementia will not see you if you come up to them from behind or the side. Without peripheral vision they will not see a plate of food in front of them.

Caregiver tip:

  • Keep in mind that the person with dementia may only see things directly in front of them. You will startle and frighten them if you approach from behind. Try to stand directly in front of them before you speak.
  • Serve finger foods at meal time. These are easier to recognize. If helping with feeding, try to direct the person to look at the food before offering a bite.

5. Problems with depth perception

Advanced dementia can cause the brain to see from only one eye. What they see becomes too much for the brain to process. To cope, the brain only uses information from one eye. This affects the ability to know how far you are from an object. The difference between a flat surface or a raised surface may not be clear.

You might notice your care partner steps too highly over a change in flooring. They could try to go around a shadow. Without depth perception, the dark spot may look like a hole.

A loss of depth perception can cause strange behaviors. For example, you might think a person with dementia is hallucinating. They may pick at the air around them. They are actually trying to touch something but can’t tell how far away it is. When they pick at the air in front of them, they may be trying to turn off a ceiling light.

Caregiver tips:

  • Avoid placing dark rugs on the floor.
  • Paint the edge of the stairs to make it easier to see each step.
  • Increase the amount of lighting. A dark corner may appear frightening.

The behaviors that look strange are a result of how they see the world.

What Is Posterior Cortical Atrophy?

Posterior Cortical Atrophy (PCA) is a form of dementia that causes visual problems. Typically, the symptoms involve difficulty seeing more than one thing at a time. Memory and cognitive problems may be milder than Alzheimer’s disease. Although the disease also causes loss in memory and cognition.

Most people will seek help for vision changes caused by Posterior Cortical Atrophy. PCA is a brain disease, not an eye problem. Other symptoms often include:

  • Memory changes
  • Behavioral changes
  • Anxiety
  • Irritability
  • Apathy
  • Depression

PCA often occurs at a younger age than Alzheimer’s disease.

How to Help a Person Cope with Vision Changes

Visual difficulties can cause frustration for the caregiver. Understanding the why behind strange behaviors will help you. Look at how you can rearrange the environment to make it safer for the person with vision loss or dementia.

Become familiar with the normal changes in vision that occur. If you notice any vision changes, see either an ophthalmologist or optometrist for regular eye exams.

Allow for extra time to complete regular activities. Slow down and offer plenty of encouragement. See the world through the eyes of a person with dementia.

Don’t forget to find support for yourself. Dementia behaviors can be strange and frustrating. You can feel alone and confused. Attending a dementia support group can help you better understand these behaviors.


  1. Causes of Visuoperceptual Difficulties
  2. How Alzheimer’s Disease Affects Vision and Perception
  3. A Form of Dementia that Affects Vision: Posterior Cortical Atrophy
  4. Aging and Your Eyes

Other Chapters in Dementia Care Guide: Strategies for Providing Compassionate, Effective Dementia Care:

  • Chapter 1

    How Vision Changes with Dementia

  • Chapter 2

    Can Dementia Come And Go?

  • Chapter 3

    Communication in the Early Stages of Dementia

  • Chapter 4

    Communication in the Middle Stages of the Dementia Journey

  • Chapter 5

    Effective Communication in Late Stage Dementia

  • Chapter 6

    Strategies for Dealing with Sundowners Syndrome (aka Sundowning) in Seniors

  • Chapter 7

    Try This Instead of Antipsychotic Drugs for Paranoia in Dementia


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