Changes in eyesight linked to early signs of Alzheimer’s and dementia: Study

Your eyes can reveal a lot about your brain health. According to new research, changes in one's visual sensitivity can indicate signs of dementia around 12 years earlier than the official diagnosis.

How did the researchers conduct this study?

Researchers followed 8,623 healthy individuals in Norfolk, England, for several years. Among them, 537 developed dementia. By analysing the data from the study, researchers identified factors that might precede a dementia diagnosis.

The visual sensitivity test

Researchers gave the participants a visual sensitivity test at the start of the study. The test required them to identify a triangle among moving dots. The ones who were slower to spot the triangle later developed dementia.

Visual signs of dementia

• Visual issues could be a warning sign of cognitive decline. Alzheimer's disease first affects areas of the brain linked to vision before damaging memory-related regions, according to studies. Thus, vision tests could detect signs of memory disorders.
• Alzheimer's also affects contrast sensitivity and the ability to discern colours may be impacted early on. These impairments can affect daily life without immediate awareness.
• One early sign of Alzheimer's is difficulty in controlling eye movements, especially in ignoring distracting stimuli. This issue might increase the risk of accidents, particularly while driving.
• People with dementia may struggle to process new faces efficiently. They may not follow the usual pattern of scanning a person's face during conversation, making them seem distant or lost.

Eye movement could help improve memory

Studies suggest that eye movement might enhance memory performance. Watching TV or reading, activities involving frequent eye movements could potentially lower the risk of dementia.

What are some limitations of this study?

Despite promising findings, using eye movements as a diagnostic tool for Alzheimer's faces challenges. Access to expensive and complex eye-tracking technologies remains a barrier. Until more accessible options are available, widespread use of eye movements in diagnosis remains limited.