Dementia is a common condition. It is estimated that 850,000 people in the UK are living with dementia and over 40,000 of these are under 65. As dementia is more prevalent in the older age group where eye diseases are also more common, it is very important to continue with regular eye examinations.
Dementia itself is not a disease, but rather a term for symptoms such as memory loss, confusion and personality change. Dementia is caused by diseases of the brain, of which Alzheimer’s being the most common. Other causes include vascular dementia, dementia with Lewy bodies and frontotemporal dementia.
Sight loss is typically under-diagnosed in people with dementia because one condition can mask or be mistaken for another. Recent studies into the prevalence of dementia and sight loss found nearly one third of people with dementia also had significant sight loss. Almost half of the study participants could have their sight loss corrected by wearing up-to-date spectacle prescriptions.
Charles Bonnet Syndrome is an under- recognised condition often confused with dementia. It is vital that this is recognised as it causes visual hallucinations and distress in people with sight loss who usually do not have dementia but may have been misdiagnosed. Visit www.nhs.uk/conditions/charles-bonnet-syndrome/ for more information.
Sight loss among people with dementia affects an estimated 250,000 people with dementia in the UK & can be caused by:-
- An eye condition; i.e cataract
- Other health conditions such as stroke
- Normal ageing of the eye, and
- Dementia itself.
In cases where sight loss is due to the dementia itself, there may be visual difficulties, specifically problems with perception, but healthy eyes. These are caused by the effect of dementia on the brain. Our optometrists can help differentiate whether the cause of the visual difficulty is due to dementia or not.
With healthy eyes, dementia can cause perceptual problems affecting:
- recognising people,
- coping with bright light, low light or potentially both
- finding things
- avoiding obstacles
- locating food on your plate
- seeing well with your current glasses.
Whilst some of the above can be attributed to the dementia, sight loss could be a contributing factor.
If you have dementia you should have regular eye tests to check both vision and eye health. Your optometrist can give advice about eye health and ensure that the correct glasses are worn. If you’re the carer of a person with dementia, they may be unable to tell you about changes to their sight. It is therefore vital to ensure that regular eye examinations are undertaken.
So what next…
- follow the thee C’s; Make sure glasses are always current, clean and correct
- make sure glasses fit well
- ensure there is good, even lighting to reduce shadows
- plain backgrounds rather than patterns are helpful
- where prescribed, ensure eye drops are taken
- when visiting the optometrist let him/her know you or the person you care for has dementia