Dementia is associated with vision impairment, but the exact relationship isn’t fully understood.

Dementia often occurs alongside eyesight problems, possibly because dementia and vision issues are more common as you age. This can cause additional confusion and upset for the person with dementia.

Dementia affects the parts of the brain that process visual information. This might make it difficult to see and process what you’re seeing. As a result, a person with dementia could have healthy eyes but still struggle to see clearly.

Maintaining healthy vision and correcting vision problems can help you maintain a high quality of life, especially if you have dementia.

Dementia and vision loss often co-occur.

Dementia develops from the degeneration of neurons (brain cells) or changes in how neurons function. This results in cognitive decline.

When we see, our eyes take in information from the objects that surround us. Light reflects into our eyes, which feed into the lens, the retina, and then the optic nerve. The optic nerve transmits information from the retina to the brain. Our brain then processes this information.

Neural degeneration can affect the parts of your brain that process sight. Although it’s possible to have dementia and healthy eyes, the degeneration of your neurons might make it more difficult to see.

Dementia and vision problems might also co-occur because both conditions are more common among older adults. Age-related vision loss can develop from conditions like macular degeneration and cataracts.

A 2023 research review found that visual impairment is actually associated with an increased risk of dementia. In fact, people with visual impairments had a 60% higher risk of developing dementia or cognitive impairment.

However, the nature of this link isn’t clear. More research is needed to determine whether vision loss could cause cognitive decline or vice versa.

What does dementia vision look like?

In dementia, vision impairment can include a range of sight issues. A person’s vision will depend on their specific eye condition if they have one. Not all people with dementia will have the same vision issues.

You can’t tell whether someone has dementia by looking in their eyes or at their face.

However, their facial expressions might seem inappropriate for certain situations. For example, a person with dementia might laugh in serious situations or cry without a discernible cause. They might also appear confused.

You might also notice changes in their personality or mood. They might appear depressed, or be more frustrated or angry than usual. This might be perceptible through their nonverbal body language, such as their facial expression or gestures.

If you’re concerned that you or a loved one is experiencing cognitive decline, reach out to a doctor about getting screened for dementia.

Although more research is needed on the link between dementia and visual impairment, some research has identified specific eye conditions associated with dementia.

Researchers in a 2021 study investigated whether visual impairments could contribute to the development of dementia.

Researchers found that age-related macular degeneration when in combination with stroke, heart disease, diabetes, high blood pressure, and depression was linked to an increased risk of dementia.

Researchers also found that cataracts and diabetes-related eye disease were associated with a higher risk of dementia. However, it’s unclear whether these eye conditions caused dementia or vice versa, or whether a third mediating factor is at play.

If you or a loved one has dementia, it’s worth speaking with an eye doctor regularly. They can help detect and correct possible eye problems, which can improve your quality of life.

Sometimes, vision changes might be mistaken for hallucinations in people with dementia.

For example, a person with dementia and compromised depth perception might try to hold something that’s farther away from them than they think. It can appear as if they’re grabbing at air, but they’re actually underestimating their distance from the object.

Similarly, they might struggle to recognize a person because their eyesight is compromised, and mistakenly call them by another name. It may seem like they’re hallucinating, but they’re not.

That said, it is possible for someone with dementia to hallucinate. They might see, hear, smell, feel, or taste something that’s not actually there.

If you think you or a loved one is experiencing hallucinations, talk with a doctor. If you’re not sure whether visual impairment may be playing a role, consider making an appointment with an eye doctor.

You can’t tell whether someone has dementia by looking in their eyes. However, vision loss commonly occurs among people with dementia.

It’s not clear whether vision loss causes dementia or vice versa. It may be that both sight loss and dementia are more common among older adults.

Whether you have dementia or not, it’s advisable to have your vision checked regularly. You can ensure that your glasses or corrective lenses are up to date and clean. Caring for your vision (or your loved one’s vision) can improve your quality of life.