Dementia is a broad term used to describe a decline in mental ability that is severe enough to interfere with daily life. There are many different types of dementia, with Alzheimer’s disease being the most common. Dementia is not a normal part of aging, although age is the biggest risk factor. Other risk factors include family history, head injury, and heart disease. Dementia affects different people in different ways, but common early symptoms include memory loss, difficulty performing familiar tasks, problems with language, disorientation, and changes in mood and behavior.
Does dementia affect vision?
Yes, dementia can affect vision in several ways. However, it’s important to note that not all visual changes are due to dementia itself. Some may be related to normal age-related eye diseases like cataracts, glaucoma or macular degeneration. That said, here are some of the ways dementia can impact vision:
- Impaired visual processing – Dementia damages parts of the brain involved in visual processing, making it harder to interpret what the eyes see. This can cause issues like misperceiving shapes, sizes or colors.
- Problems with depth perception – Dementia can disrupt depth perception, making it difficult to judge distances. This increases fall risk due to tripping on curbs or stairs.
- Impaired contrast sensitivity – Dementia often reduces contrast sensitivity, making it harder to distinguish objects from their background. Reading becomes difficult when there is low contrast between the text and page.
- Visual hallucinations – Some dementia patients experience visual hallucinations like seeing animals, people or patterns that aren’t really there. This is common in Lewy body dementia.
- Difficulty with eye movement – Dementia can cause problems controlling and coordinating eye muscles leading to complaints like blurry vision, double vision, involuntary eye movements.
- Impaired visual memory – Dementia damages brain areas involved in visual memory, so patients have trouble recognizing faces or navigating due to forgetting familiar routes.
How do different types of dementia affect vision?
Different dementia types can affect vision in varying ways:
Alzheimer’s disease
- Impaired ability to identify objects, colors and read
- Inability to recognize faces (even close family)
- Difficulty navigating and judging distance
- Problems moving the eyes or experiencing jerky eye movements
Vascular dementia
- Blurry vision or partial vision loss from stroke damaging the brain’s visual cortex
- Difficulty perceiving movement and seeing only fragments of motion
- Problems looking up and down
- Sudden onset of visual hallucinations
Lewy body dementia
- Well-formed recurrent visual hallucinations like seeing animals, people, or patterns
- Fluctuating vision with both clear and blurry periods
- Difficulty judging distances and seeing stationary objects move around
- Eyelid apraxia where lids won’t open or close properly
Frontotemporal dementia
- Involuntary eye movements like constant blinking or eyes deviating upwards
- Impaired object recognition and loss of facial recognition skills
- Difficulty voluntarily moving the eyes from one object to another
- Reduced visual awareness and reaction to sights and movements in the environment
How are visual problems diagnosed in dementia patients?
A comprehensive eye exam is key to diagnosing any visual changes in dementia patients. The eye doctor will:
- Test visual acuity to check sharpness of vision at all distances
- Evaluate peripheral vision
- Check eye movements and coordination
- Test contrast sensitivity
- Examine the condition of the optic nerve
- Evaluate depth perception
- Look for signs of eye diseases like cataracts, glaucoma and macular degeneration
- Refer the patient to a neuroophthalmologist if neurological disorders are suspected
The patient’s medical history and description of symptoms will help distinguish vision problems from dementia versus other age-related eye diseases. Brain imaging and cognitive testing can aid diagnosis too.
Treatments for visual disturbances with dementia
While there is no cure for the visual effects of dementia, some helpful treatments include:
- Corrective lenses – Glasses optimized for contrast, lighting conditions, depth perception and field of vision deficits.
- Prism lenses – Lenses with prism correction for diplopia (double vision).
- Vision therapy – Exercises to strengthen eye movement control and coordination.
- Environmental modifications – Improved lighting, handrails, reduced clutter and high-contrast markings to ease navigation.
- Medication – Drugs to treat symptoms like hallucinations may alleviate visual disturbances.
- Low vision rehabilitation – Training in special techniques and devices to help maximize remaining vision.
- Cataract surgery – Removing cataracts to improve contrast, reduce glare and increase visual acuity if appropriate.
Supportive care from eye doctors, neurologists and occupational therapists can also help dementia patients cope with visual changes.
Caring for someone with dementia-related vision problems
If you are caring for someone with dementia and vision issues, here are some tips that can help:
- Have their vision tested regularly to address any new issues promptly.
- Ensure proper lighting through their living space by using ample ambient light plus task lighting.
- Reduce clutter than can cause confusion or tripping.
- Use contrast by painting doors and walls different colors.
- Mark steps and thresholds with bright tape for better visibility.
- Encourage wearing glasses and check they are clean and fitted properly.
- Provide large-print books and playing cards to aid interaction.
- Don’t rearrange furniture so pathways stay familiar.
- Gently remind them of people’s names and faces.
- Be patient in communicating and understanding their perspective.
With compassion and creativity, the burdens of dementia-related vision loss can be reduced. Seek professional advice for specific needs.
Conclusion
Dementia can significantly impact vision and visual perception. Different types of dementia affect the eyes in varying ways, but some common symptoms include impaired object/face recognition, poor depth perception, visual hallucinations, and problems with eye movements. Comprehensive eye exams along with cognitive testing are needed to properly diagnose visual disturbances caused by dementia. While there is no cure, treatments like specialized glasses, prism lenses, vision therapy, environmental modifications and medication can help maximize remaining vision and ease difficulties. Caring for those with dementia and visual deficits requires regular eye checks, a safe living space, visual aids and lots of patience. With a supportive approach, it is possible to minimize the challenges of dementia-related vision loss.