PrOVIDe: Prevalence of Visual Impairment in Dementia

Background

Demographic research predicts an ageing UK population resulting in increasing prevalence of dementia and the major causes of visual impairment (VI). A brief review of literature on VI and dementia revealed inconclusive prevalence data due to methodological differences in subjects’ age, research setting (care home residents and non residents) and definitions of VI. Furthermore, much of the research is 10-30 years old and few studies were UK based. 

This led to identification of the main research question which was:  What is the prevalence of a range of vision problems in people with dementia aged 60-89 years and to what extent are these conditions undetected or inappropriately managed? 

Acknowledgements and disclaimer

HS&DR Funding Acknowledgement:
This project was funded by the National Institute for Health Research Health Services and Delivery Research Programme (project number 11/2000/13).

Department of Health Disclaimer:
The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the HS&DR Programme, NIHR, NHS or the Department of Health.

Objectives

  1. To measure the prevalence of a range of vision problems in people with dementia. 
  2. To compare the prevalence found with the published data on the general population in a comparable age range. 
  3. To identify and describe reasons for any under detection or inappropriate management of visual impairment in people with dementia. 
  4. To recommend interventions to improve eye care for people with dementia and further research in this area.

The project

The project was in two stages. Stage 1 was a prevalence study, with over 700 eye examinations being given to patients with dementia to gather the data that can be compared to the general population. Stage 2 consisted of focus groups and interviews with eye care professionals, professional carers, family carers and people with dementia to investigate any issues around the management of visual impairment in people with dementia. The project involved extensive collaboration, with input from primary care, old age psychiatry, professional care and ophthalmology and working partnerships with 17 dementias and neurodegenerative diseases research network (DeNDRoN) sites and a national domiciliary provider (The Outside Clinic).

Final report

The study was published in the Health Services and Delivery Research journal in July 2016. The project also informed a proposal for a UK Dementia Eye Care Pathway, which was published in Volume 16 Issue 2 of the College's CPD journal Optometry in Practice.

The study’s key findings were:

  • 32.5% 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% of those with VI were no longer classified as visually impaired when wearing their up-to-date spectacle prescription.
  • 22% 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 ten 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% 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.
There are approximately 850,000 people living with dementia in the UK.

Dementia summit

This joint event was held to generate ideas on how to turn the findings from research into recommendations that will improve the lives of those living with dementia and vision impairment. A report from the event was published in March 2016.

Visual Impairment and Dementia (VIDem) summit report

Member briefing

This member briefing includes an outline of the research findings and how it might affect you in practice.