Vision loss and the risk of dementia

Causes of vision loss

It is estimated that 2 million people in the UK have vision loss. This is defined as not being able to read more than half the way down the optician’s eye chart. Nearly 80% of the people with vision loss are over the age of 65.

Vision loss can have difference causes and is more common in older people. It can broadly be separated into three categories:

• Vision loss alone – which is caused by a condition or disease of the eye. The most common in the UK are age-related macular degeneration, glaucoma, and cataracts.
• Disease related vision loss – where another disease leads to someone developing vision loss e.g. diabetic retinopathy. Diabetes is also a risk factor for dementia.
• Neurological vision loss – loss of vision with neurological causes such as problems with the nerve cells in the eye or the brain.

The link between vision loss and dementia risk

Research shows that people with vision loss are about 50% more likely to develop dementia than people without vision loss.

A study that compared specific eye conditions found that cataracts and diabetic retinopathy were both associated with increased dementia risk, whereas glaucoma and age-related macular degeneration were not.

People with vision loss may also be more likely to avoid social situations and become more isolated over time. Social isolation and depression are both risk factors for dementia.

Treating or correcting vision loss may be beneficial at reducing dementia risk. Taking cataracts as an example, one study showed that people who had cataracts removed were 30% less likely to go on to develop dementia than those who did not. Another study found that the dementia risk of people who had cataract surgery was the same as people who did not have cataracts.