Research led by the College of Optometrists found that prevalence of visual impairment (VI) in those with dementia is generally higher than for the overall population, highlighting the importance of sight tests in this group of people.
The college’s research also found that almost 50 per cent of those living with dementia and VI were no longer classified as visually impaired when wearing their up-to-date spectacle prescription and that VI was approximately 2-2.5 times more common for those people with dementia living in care homes than for those living at home.
The research, entitled the Prevalence of Visual Impairment in People with Dementia (PrOVIDe), was led by the College of Optometrists in collaboration with City, University of London, University of Birmingham, Thomas Pocklington Trust, Alzheimer’s Society, University of Newcastle, Trinity College Dublin and University College London and was funded and published by the National Institute for Health Research. The project also benefitted from in-kind support from the Outside Clinic.
The study aimed to measure the prevalence of a range of vision problems in people with dementia aged 6 to 89 years to determine the extent to which their vision conditions are undetected or inappropriately managed.
The study’s key findings were:
- 5 per cent of people with dementia had visual acuity (VA) worse than 6/12 (the legal standard for driving) and 16.3 per cent had VA worse than 6/18 (a commonly used international standard for defining when someone is ‘visually impaired’). These figures are generally higher than in comparable data from prevalence studies on the general population (after adjustment for age and gender)
- Almost 50 per cent of those with VI were no longer classified as visually impaired when wearing their up-to-date spectacle prescription
- 22 per cent of participants reported not having had a sight test in the previous two years, including 19 participants who had not been tested in the last 10 years
- VI was approximately 2-2.5 times more common in those living in care homes than for those living in their own homes, even after age and gender had been controlled for
Once refractive error was accounted for:
- Cataract was the primary cause of VI in those with VA worse than 6/12. Cataract is treatable with surgery in suitable patients
- Age-related macular degeneration (AMD) was the primary cause of VI in those with VA worse than 6/18
- 16 per cent of participants could not read standard newspaper-size print with their current spectacles, however almost two thirds of these participants could read this print wearing a prescription given following a dementia-friendly sight test
Of particular note to practising optometrists, the study highlighted:
- The need to allow more time when examining people with dementia. For individuals having an eye examination who are accompanied by a carer or professional care worker, it’s important that the care worker knows the individual and has relevant information to hand. Their input is described by participating optometrists as ‘invaluable’
- Optometrists are not always informed that an individual has dementia before their examination takes place. This knowledge is a very significant factor in achieving the best outcome for the individual
- Optometrists did not feel enough training and support is provided to examine people with dementia
- Carers and care workers were unsure that people with dementia could have a full eye examination if they had difficulty answering questions, however it was possible to conduct key components of the exam with more than 80 per cent of people examined