The prevalence of visual impairment (VI) increases rapidly with age. It is estimated that more than one in 10 of the older UK population suffer from significant visual impairment, and this rises to one in three of those more than 90 years old.1 Unfortunately, it is also the older age group that are at higher risk of having multiple health conditions or ‘comorbidities’ – both physical and mental.

For the VI patient additional health problems can compromise both health and rehabilitation outcomes, including reduced quality of life, disability and increased inpatient admissions.2-7

Although we know that visual impairment is common in the older population, there is limited data that describes the nature and extent of comorbidities in this group. Crews and Van Nispen8,9 both reported studies which identified that comorbidities are more common in people with visual impairment. However, these studies were limited by self-report measures and by a relatively limited number of assessed comorbid conditions. Furthermore, neither of these studies were in a UK context.

Understanding the nature and extent of comorbidities in visually impaired patients will have implications upon our care of patients at both a practice level and at co-ordinating care/services level. The rest of this article will describe the results of a large UK-based study of visual impairment and comorbidity, and how these findings translate into patient care.

A large UK-based visual impairment and comorbidity study

The study was undertaken by a group of researchers at Glasgow University, Scotland.11 The data used for analysis was from the Primary Care Clinical Informatics Unit at the University of Aberdeen. This database contained medical information for 1.7million registered patients who were alive and permanently registered with over 300 Scottish GP practices in March 2007. Importantly, the included patients were representative of the whole Scottish population in terms of age, gender and socioeconomic status.

From this database, 32 common chronic physical health conditions (including VI) and eight mental health conditions were extracted for analysis. The analysis was restricted to those 65 years and older, in order to focus on age-related visual impairment. This resulted in a sample of 5,348 patients coded for visual impairment, which was roughly 2% of the total sample (the rest of the sample being the control group).

Older patients with visual impairment have more medical comorbidities compared to the non-visually impaired

Odds ratios (OR) and 95% confidence intervals (CI) were calculated for those with visual impairment compared to those without (controls) for the prevalence of 29 physical conditions (two conditions were excluded: glaucoma since it is purely an ocular condition and viral hepatitis because only one person with VI had this condition) and eight mental health conditions, as well as for the number of overall conditions.

It is important to note that because the data came from records within a primary care database it may not be as accurate or consistent as it would in a more formal epidemiological survey. But, compared to the relatively few studies which have examined comorbidities in VI, the main strength of this study was the large sample size and the assessment of a much wider range of comorbid physical and mental conditions.

The prevalence of comorbidities in people with visual impairment

The results of the analysis showed that older patients with visual impairment were characterised by more medical comorbidities compared to non-visually impaired. Indeed, those in the visual impairment group were significantly more likely to have four conditions (VI 15.4% versus controls 11.7%; OR 1.17 95% CI 1.08-1.26) and twice as likely to have five or more conditions (VI 37.4% versus controls 17.8%; OR 2.05 95% CI 1.94-2.18). This was the case even after the standardising for age, gender and social deprivation.

Table 1 shows a summary of the prevalence for individual physical and mental health conditions. Apart from two physical health conditions (bronchiectasis – an abnormal widening of the bronchioles that increases the risk of infection – and migraine), all physical and mental health conditions were significantly more prevalent in the visual impairment group compared to controls.

Table 1: Prevalence for individual physical and mental health conditions (standardised by age, gender and deprivation score)10

The most prevalent conditions were hypertension (at 56%), coronary heart disease (at 29%) and diabetes (at 26%). Depression was the most prevalent mental health condition at 18%.

It is important to remember that this was a cross-sectional study. This means that we cannot infer cause and effect from the data. However, we do know that many chronic conditions have visual consequences. For example, optic neuritis occurs in about 70% of multiple sclerosis cases, and the ocular complications of diabetes account for the majority of blind registrations among working age adults and stroke causes VI in 30% of cases.11

Implications for clinical practice

There are number of potential implications from this study for both optometrists and wider healthcare services:

The importance of lifestyle advice

This study suggests that older adults with VI are characterised by more medical comorbidities that those without VI. And so informed lifestyle advice in the consulting room may be helpful.

The most prevalent conditions in the VI group were hypertension, coronary heart disease and diabetes. What is interesting about these conditions is that we know that VI may pose significant barriers to encouraging a healthy lifestyle – so for example VI may contribute to a compromised diet (due to difficulty preparing food), increased difficulty engaging in exercise, and high levels of isolation. And so a vicious cycle may occur – ‘I have high blood pressure, I need a healthier lifestyle, but my VI restricts my ability to engage in that, and so my blood pressure may suffer’and so it goes on (figure 1).

For this reason, when we see patients with these comorbidities it could be helpful to find out how they are coping accessing a healthy lifestyle. Are there any support groups or events in your area which a patient could connect with – to help them get out and exercise? Is the patient able to see their medication? Are their current visual aids fit or purpose, or is there something better we can suggest? Spending some time finding out what support networks and services are available for people with VI could provide a huge benefit to some of your patients – many of whom are at risk of social isolation. It also is important to ensure that any advice given in the consulting room is also provided to the patient in written format, as we know that there are high levels of poor recall of information in optometric patients, especially when the patient is feeling anxious about their vision.

As the population continues to age, the number of patients who have multiple health and mental health comorbidities will increase

Depression a key factor

Secondly, as will be discussed in a forthcoming Optician article from Dr Tom Margrain’s team at Cardiff University, clinicians also need to be alert to depression in this group. Depression was the most prevalent mental health condition in the VI group (18%), and Margrain’s work suggests that clinical depression is even higher when measured in low vision clinic patients (43%). Depression is a debilitating illness, and can lead to a reduction in engagement in services and support networks which provide rehabilitation. At present, there appears to be little in the way of referral pathways from optometry to secondary care for patients with depression in the UK, however, there is growing evidence to suggest that this would be of huge benefits to patient care. In the absence of formal screening measures and pathways, clinicians can still be mindful of depression, and encourage patients to see their GP if they are feeling overwhelmed or provide information about local networks or support services. There are many helpful websites about depression if you want further information, including the mental health charity Mind (mind.org.uk).

Don’t overlook hearing loss

Thirdly, it was found that comorbid hearing loss was identified in 18% of VI patients in this study compared to only 9% of controls. Hearing loss is commonly under-diagnosed in primary care services and evidence suggests that 45% of people reporting hearing loss to their GPs are not referred for further intervention (Government of Scotland, 2013).12 People with dual sensory loss (sight and hearing) are at risk of loss of functional independence, increased risk of falls and mortality.13,14 For this reason, it is important that optometrists are alert to possible hearing problems in all older patients, especially those with reduced vision.

There have been recommendations made to integrate formal hearing screening tests into eye care and rehabilitation services, which could substantially increase the numbers of people identified with hearing loss.15,16 Formal procedures will facilitate optometric clinicians in dialoging with patients about possible referral for hearing assessment. In the meantime, if clinicians feel able to open a discussion about hearing loss, they can suggest referral to the GP, or there are a variety of online screening tests which patients can be signposted to. A helpful resource for materials, online hearing screening and further information is Action on Hearing Loss (actiononhearingloss.org.uk).

Keep an eye on patient medications

Visually impaired patients with multiple comorbidities are likely to be on a list of different systemic medications. As clinicians, it is helpful to be aware that some systemic drugs can also contribute to falls, for example hypotensive and hypoglycaemic agents, bladder anticholinergics and psychotropic drugs.

A Scottish study sought to determine the incidence of severe hypoglycaemia attacks in diabetic patients.17 The results showed that over a one year period, the incidence was 1 in 2,000 for patients taking metformin, and 1 in 100 for those people taking a sulphonylurea (eg gliclazide, glipizide, tolbutamide). Hypoglycaemia is an independent risk factor for falls. This suggests it would be helpful to ask a VI patient taking a sulphonylurea if they have had any episodes of hypoglycaemia recently and communicate with the GP if you are concerned about the patient and suggest a review of patient medication.

Working together

As the general population continues to age, the number of patients we manage who have multiple health and mental health comorbidities will increase – both patients with and without VI. To provide safe and effective care which seeks to make use of current healthcare services effectively, we will need to move towards more integrated working with other areas of healthcare. The World Health Organisation defines integrated services as follows:

‘The management and delivery of health services so that clients receive a continuum of preventive and curative services, according to their needs over time and across different levels of the health system.’18

This type of working is not readily accessible because in the UK we work in a healthcare system which tends towards independent specialist driven services. However, being mindful of that current status, we still need to actively engage with the need to create clear communication and pathways between our optometric services and those services which we are referring/signposting to. There are examples across the UK where there are advancements with integrating services. Within Wales and Scotland there has been recent evidence of a Governmental commitment to tackling comorbid depression and dual sensory loss at national levels19. As previously mentioned, in Wales there is also ongoing work to move toward integrating depression screening into low vision services. These advancements represent a move towards integrating services, but continuing integration to provide holistic care for patients will require more evidence-based recommendations and commitment from the healthcare community.

At a local level, facilitating improved communication between healthcare professionals could include initiating a peer discussion group and inviting a range of other healthcare professionals in your area. This could include pharmacists, ophthalmologists, and diabetic and stroke consultants. Intentionally establishing good relationships will enable us to effectively move forward in providing safe and timely care to patients.

Key findings of studies into Visual impairment (VI)

  • More than 1 in 10 older patients in the UK suffer with VI
  • Older patients with VI are characterised by more medical comorbidities compared to those without VI
  • Patients 65+ years with VI, are twice as likely to have five or more physical/mental health comorbidities compared to those without VI
  • The most prevalent physical health conditions in VI patients are: hypertension, CHD and diabetes
  • The most prevalent mental health conditions in VI patients is
  • depression
  • Improving care for VI patients will require active integration of healthcare services

Conclusion

The study described in this paper identifies that patients aged 65 years and older with visual impairment have a broad range of physical and mental health comorbidities compared to those of the same age without visual impairment, and are more likely to have multiple comorbidities. This has important implications for our management of patients in clinical practice and for the future design of integrated healthcare services to meet the complex needs of patients with visual impairment.

Dr Helen Court is a research optometrist based in Scotland

References

1 Evans JR, Fletcher AE, Wormald RPL, Siu-Woon Ng E, Stirling S, Smeeth L, Breeze E, Bulpitt CJ, Nunes M, Jones D, Tulloch A: Prevalence of visual impairment in people aged 75 years and older in Britain: results from the MRC trial of assessment and management of older people in the community. Br J Ophthalmol. 2002, 86: 795-800.

2 Fortin M, Lapointe L, Hudon C, Vanasse A, Ntetu AL, Maltais D: Multimorbidity and quality of life in primary care: a systematic review. Health Qual Life Outcomes. 2004, 2: 51-10.1186/1477-7525-2-51.

3 France EF, Wyke S, Gunn JM, Mair FS, McLean G, Mercer SW: Multimorbidity in primary care: a systematic review of prospective cohort studies. Br J Gen Pract. 2012, 62: e297-e307.

4 Gijsen R, Hoeymans N, Schellevis FG, Ruwaard D, Satariano WA, van den Bos GA: Causes and consequences of comorbidity: a review. J Clin Epidemiol. 2001, 54: 661-674. 10.1016/S0895-4356(00)00363-2.

5 Goldstein JE, Massof RW, Deremeik JT, Braudway S, Jackson ML, Kehler KB, Primo SA, Sunness JS: Baseline traits of low vision patients served by private outpatient clinical centers in the United States. Arch Ophthalmol. 2012, 130: 1028-1037. 10.1001/archophthalmol.2012.1197.

6 Marengoni A, Angleman S, Melis R, Mangialasche F, Karp A, Garmen A, Meinow B, Fratiglioni L: Aging with multimorbidity: a systematic review of the literature. Mech Ageing Dev. 2011, 10: 430-439.

7 Whitson HE, Steinhauser K, Ammarell N, Whitaker D, Cousins SW, Ansah D, Sanders LL, Cohen HJ: Categorising the effect of comorbidity: a qualitative study of individuals’ experiences in a low-vision rehabilitation program. J Am Geriatr Soc. 2011, 59: 1802-1809.

8 Crews JE, Jones GC, Kim JH: Double jeopardy: the effects of comorbid conditions among older people with vision loss. J Visual Impairment Blindness. 2006, 100: 824-848.

9 van Nispen RM, de Boer MR, Hoeijmakers JG, Ringens PJ, van Rens GH: Comorbidity and visual acuity are risk factors for health-related quality of life decline: five-month follow-up EQ-5D data of visually impaired older patients. Health Qual Life Outcomes. 2009, 7: 18-10.1186/1477-7525-7-18

10 Court H, McLean G, Guthrie B, Mercer SW, Smith DJ. Visual impairment is associated with physical and mental comorbidities in older adults: a cross-sectional study. BMC Med. 2014 Oct 17;12:181.

11 Sand KM, Midelfart A, Thomassen L, Melms A, Wilhelm H, Hoff JM: Visual impairment in stroke patients-a review. Acta Neurol Scand Suppl. 2013, 196: 52-56.

12 Government of Scotland: See Hear: A Strategic Framework for Meeting the Needs of People With a Sensory Impairment in Scotland. Edinburgh: 2013.

13 Kiely KM, Anstey KJ, Luszcz MA: Dual sensory loss and depressive symptoms: the importance of hearing, daily functioning, and activity engagement. Front Hum Neurosci. 2013, 7: 837-

14 Gopinath B, Schneider J, McMahon CM, Burlutsky G, Leeder SR, Mitchell P: Dual sensory impairment in older adults increases the risk of mortality: a population-based study. PloS One. 2013, 8

15 Davis A, Smith P: Adult hearing screening: health policy issues – what happens next?. Am J Audiol. 2013, 22: 167-170.

16 Schneider J, Dunsmore M, McMahon CM, Gopinath B, Kifley A, Mitchell P, Leeder SR, Wang JJ: Improving access to hearing services for people with low vision: piloting a ‘hearing screening and education model’ of intervention. Ear Hear. 2014, 35: e153-e161.

17 Leese GP, Wang J, Broomhall J, Kelly P, Marsden A, Morrison W, Frier BM, Morris AD; DARTS/MEMO Collaboration. Frequency of severe hypoglycemia requiring emergency treatment in type 1 and type 2 diabetes: a population-based study of health service resource use. Diabetes Care. 2003 Apr;26(4):1176-80.

18 World Health Organisation, 2008: who.int/healthsystems/service_delivery_techbrief1.pdf

19 Together for Health: Eye Health Care. 2013 (wales.nhs.uk/documents/Eye-Health-Care-Delivery-Plan-Wales-e.pdf)