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Predicting the need for low vision rehabilitation services P M O’Connor, E L Lamoureux and J E Keeffe Br. J. Ophthalmol. 2008;92;252-255 doi:10.1136/bjo.2007.125955

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Clinical science

Predicting the need for low vision rehabilitation services P M O’Connor,1,2 E L Lamoureux,1,2 J E Keeffe1,2 1

Centre for Eye Research Australia, University of Melbourne, Australia; 2 Vision CRC, Sydney, Australia Correspondence to: Dr P M O’Connor, Centre for Eye Research Australia, Locked Bag 8, East Melbourne 8002, Australia; [email protected] Accepted 14 September 2007

ABSTRACT Aims: To determine the independent predictors of rehabilitation needs for people with low vision using the Impact of Vision Impairment questionnaire (IVI) to measure the quality-of-life consequences of visionspecific restrictions on participation in activities of daily living. Methods: Patients attending low vision clinics completed the IVI and provided personal and clinical information such as co-morbidities and visual acuity. Rasch analysis was used to generate person measures for the IVI total and three domain scores. Rehabilitation needs were based on ‘‘mild’’, ‘‘moderate’’ or ‘‘severe’’ levels of restriction in participation as determined by the lower, moderate and higher tertiles of persons measures. Logistic regression analyses were used to determine independent predictors of rehabilitation needs. Results: 477 patients (56% women) with a mean age 72 years (SD 15.3) were recruited. Most (74%) had moderate or severe vision loss (presenting visual acuity (VA),6/18), and 43% had age-related macular degeneration (AMD). Females, shorter duration of vision impairment, having AMD, worse VA, a greater impact of co-morbidities on daily living and reliance on family or friends were univariately associated with poorer IVI scores (p,0.05). In all regression models, VA, the impact of comorbidities on daily living and dependence on family/ friends emerged as the three strongest independent predictors of rehabilitation needs. Conclusion: In addition to vision, clinicians also need to consider issues relating to dependency when assessing rehabilitation needs. A more holistic approach to patient referral and rehabilitation provision is therefore warranted.

Rehabilitation intervention can potentially benefit up to 90% of people with low vision.1 2 However, only 5–10% of the world’s 68 million persons with low vision care actually access such services.3 4 Low vision is essentially an age-related condition and with an anticipated doubling of the world’s elderly population by 2020,5 a parallel increase in those needing low vision rehabilitation will also occur. Rates of rehabilitation service uptake are influenced by a mix of factors including barriers relating to the services themselves,1–3 6–8 their low vision clients2 3 9 10 and the service providers. This paper focuses on the latter group, recognising the critical role played by health professionals in the referral process. Early referral can optimise a patient’s ability to maintain independence, and rehabilitation intervention can yield major quality-of-life (QoL) benefits.7 11–14 However, ophthalmologists typically refer proportionately few of their patients or delay such referrals until the patients approach severe vision loss.7 252

To facilitate appropriate and timely referral, eye healthcare professionals need to be aware of the patients’ characteristics that predict low vision rehabilitation needs. This paper aims to identify these predictive characteristics in view of referral and addresses the issue of quality of life from a ‘‘biopsychosocial’’ perspective. This concept is derived from the World Health Organization’s International Classification of Functioning, Disability and Health (ICF) framework and describes the amalgam of physical, psychological and social factors that combine to shape how low vision impacts day-to-day functioning. The Centre for Eye Research Australia recently developed and validated the Impact of Visual Impairment (IVI) questionnaire.15 16 The IVI is a valid scale to measure self-reported restriction on participation in daily living activities and QoL, and was used in this study to examine the predictors of rehabilitation needs in overall and specific areas of daily living in people with low vision.

DESIGN AND METHODS Consecutive consenting patients with low vision attending special eye clinics at the Royal Victorian Eye and Ear Hospital (RVEEH), Melbourne between 2001 and 2006 were recruited as study participants. Eligibility criteria included the ability to converse in English, visual acuity ,6/12, age 18 years or older and no prior referral to low vision rehabilitation. All participants completed a written consent form. Those who refused to participate were awaiting appointments and did not have adequate time available. Ethics approval for the study was obtained from the RVEEH Human Research and Ethics Committee, and the research adhered to the tenets of the Declaration of Helsinki. Socio-demographic, health and IVI data for each participant were obtained using interviewer-administered questionnaires. From an eye examination, performed on the same day as the IVI was administered, details of the cause of vision loss, presenting and best-corrected visual acuity (VA), and visual fields if tested were recorded. The IVI questionnaire was used to specifically assess participation in daily life and has been described elsewhere.15 16 Briefly, the 28-item IVI questionnaire has a four-category response scale for 26 items and a three-category response scale for two items. These items form three domains: mobility and independence (11 items); emotional well-being (eight items) and reading and access to information (nine items). Rasch analysis was used to derive a linear transformation of the IVI scores, thereby overcoming Br J Ophthalmol 2008;92:252–255. doi:10.1136/bjo.2007.125955


Clinical science Table 1 Socio-demographic and clinical characteristics of study participants (n = 477) Age (years) Gender (n, %) Main cause of vision loss (n, %)

Duration of impairment (years) Presenting visual acuity (n, %)

Co-morbidity (n, %) Effect of co-morbidity on daily living (n, %)

Hearing loss (n, %) Language (n, %) Living arrangements (n, %)

Receiving meals from family and friends (n, %) Income source (n, %)

Mean¡SD Females Males Age-related macular degeneration Diabetic retinopathy Glaucoma Other retinal Other Median, min, max Mild,6/12 to 6/18 Moderate,6/18 to 6/60 Severe,6/60 Yes No Not at all A little A great deal Yes No English-speaking English as a second language Living alone Living with spouse/partner Other Yes No In paid employment Not in paid employment

the weaknesses inherent in ordinal Likert scales.15–17 Generating an interval scale for the participants’ scores enhances the accuracy of the responses and allows the use of parametric testing to identify predictors of rehabilitation needs in the logical regression models. Differential item functioning (DIF) was used to determine if different groups within the sample (eg, degree of vision impairment, co-morbidity, gender or impact of co-morbidity on daily living), despite equal levels of the QoL, respond in a different manner to an individual item. All items were found to be free from DIF. Univariate analyses were used to identify associations between participants’ socio-demographic, vision and health characteristics and the total IVI and three domain scores. Variables found to be univariately associated (p,0.05) were used to construct four models (total IVI and three domains) to determine the independent predictors of rehabilitation needs. Rehabilitation need in this context was determined by the association between level of difficulty in participating in activities of daily living, as evident from person measure scores on the IVI, and a series of independent variables. Restrictions in participation were categorised as ‘‘mild’’, ‘‘moderate’’ or ‘‘severe’’ using tertile divisions of participants’ scores. The IVI data were analysed using SPSS statistical software (Version 14.0, SPSS Science, Chicago).

RESULTS A total of 477 patients (56% women) with a mean age of 72 years (SD 15.3) were recruited (table 1). Most (74%) had moderate or severe vision loss (VA,6/18). The most common cause of vision loss was age-related macular degeneration (44%), followed by diabetic retinopathy (22%). More than threequarters (77%) of the participants had comorbid conditions that interfered with their ability to participate in activities of daily Br J Ophthalmol 2008;92:252–255. doi:10.1136/bjo.2007.125955

71.8 268 209 207 107 63 50 49 4.0 124 243 108 367 108 110 115 141 174 271 413 64 161 214 99 132 340 31 340

¡15.4 56 44 44 22 13 11 10 0.17, 84.0 26 51 23 77 23 30 31 39 39 61 87 13 34 45 21 28 72 8 92

living either a little or a great deal (31% and 39%, respectively).The main co-morbidities reported were diabetes, heart conditions, hypertension and arthritis. While less than a quarter (24%) received local government home help services, 28% and 32% were reliant on families and friends for assistance with meals and chores respectively. Univariate analyses indicated that gender (female), shorter duration of vision impairment, having AMD, worse VA, greater impact of comorbidities on activities of daily living, and higher reliance on family/friends were associated with poorer total IVI scores (p,0.05). Similar associations were found at domain level with the exception that gender (female) was only associated with poorer scores in the mobility and independence domain. In addition, being of non-English-speaking background was positively associated with poorer emotional well-being scores, and age was associated with poorer reading and accessing information scores. Controlling for age, gender, visual acuity, co-morbidity, effect of co-morbidity, cause of vision loss, receiving meals from family/friends, duration of vision impairment, receiving family help with chores, receiving council home help (total IVI, mobility and independence, reading and accessing information domains), receiving meals on wheels (mobility and independence domain) and language (emotional well-being domain), three variables consistently ranked as the highest independent predictors of need in all four linear regression models: visual acuity, the effect of co-morbidity on life activities and reliance on family or friends for meals (tables 2 and 3). The IVI total and domain scores indicated that people with poorer VA (odds ratios ranged from 7.3 to 27.5) and those most affected by co-morbidities (odds ratios ranged from 4.4 to 4.9) were at increased risk of severe restrictions on participation. Receiving meals from family and friends also increased the likelihood of severe restriction on 253


Clinical science Table 2 Odds ratio (95% CI) Total IVI score for those with moderate or severe restriction on participation versus mild restriction on participation IVI total scores* Independent variable

Moderate restriction{

Severe restriction{

Visual acuity

Mild Moderate Severe

1 2.49 (1.34 to 4.62) 3.23 (1.27 to 8.20)

1 4.12 (1.90 to 8.95) 17.15 (6.38 to 46.06)

Effect of co-morbidity

Not at all A little A great deal

1 1.62 (0.83 to 3.16) 2.74 (1.36 to 5.53)

1 1.76 (0.81 to 3.81) 4.86 (2.22 to 10.65)

Receiving meals from family/friends

No Yes

1 2.19 (0.98 to 4.89)

1 2.75 (1.20 to 6.30)

Additional factors controlled for: age, gender, cause of vision loss, duration of vision impairment, receiving family help with chores, receiving council home help, co-morbidity. *Category Logit score Equivalent summary score {Reference group: IVI mild restriction Severe 25.109 to 20.286 0 to 35 Moderate 20.268 to 0.875 36 to 54 Mild 0.879 to 5.33 54 to 82

Table 3

Odds ratio (95% CI) Domain IVI scores for those with moderate or severe restriction on participation versus mild restriction on participation

Independent variable

IVI scores: mobility and independence

IVI scores: emotional well-being

IVI scores: reading and accessing information

Moderate restriction*

Severe restriction*



Severe restriction*

Severe restriction*

Visual acuity

Mild Moderate Severe

1 1.51(0.81 to 2.82) 3.04 (1.26 to 7.30)

1 1 4.73 (2.18 to 10.28) 2.32 (1.23 to 4.37) 11.56 (4.33 to 30.87) 3.49 (1.47 to 8.32)

1 1 2.64 (1.29 to 5.40) 4.12 (2.15 to 7.86) 7.28 (2.97 to 17.84) 5.09 (1.83 to 14.22)

Effect of co-morbidity

Not at all A little A great deal No

1 1.57 (0.81 to 3.08) 2.35 (1.16 to 4.75) 1

1 1.50 (0.71 to 3.16) 4.50 (2.11 to 9.61) 1

1 1.94 (0.99 to 3.78) 2.96 (1.48 to 5.91) 1

1 1.58 (0.75 to 3.35) 4.40 (2.12 to 9.16) 1

1 1.86 (0.92 to 3.79) 3.38 (1.60 to 7.15) 1

1 5.74 (2.64 to 12.50) 27.46 (9.56 to 78.87) 1 1.41 (0.64 to 3.09) 4.56 (2.03 to 10.21) 1

Yes Other eye conditions AMD ,60 years 60 to 79 years 80+

1.82 (0.82 to 4.01) 1

2.28 (1.03 to 5.06) 1

1.76 (0.82 to 3.79) 1

2.88 (1.29 to 6.43) 1

1.21 (0.54 to 2.74) 1

1.86 (0.80 to 4.32) 1

Receiving meals from family/friends Cause of vision loss

Age group

Additional factors controlled for:

1.69 (0.88 to 3.28) 1.51 (0.73 to 3.09) 1 1 0.71 (0.31 to 1.61) 0.54 (0.22 to 1.33) 0.46 (0.17 to 1.25) 0.47 (0.16 to 1.34) Gender, duration of vision impairment, receiving family help with chores, receiving council home help, receiving meals on wheels, co-morbidity

1.12 (0.59 to 2.15) 1.54 (0.75 to 3.16) 1 1 0.62 (0.27 to 1.47) 0.46 (0.19 to 1.12) 0.55 (0.21 to 1.41) 0.35 (0.13 to 0.95) Gender, duration of vision impairment, receiving family help with chores, language, co-morbidity

2.17 (1.07 to 4.39) 2.53 (1.19 to 5.38) 1 1 0.64 (0.28 to 1.47) 1.27 (0.48 to 3.35) 0.58 (0.21 to 1.58) 0.97 (0.31 to 3.01) Gender, duration of vision impairment, receiving family help with chores, receiving council home help, co-morbidity

*Reference group: IVI mild restriction.

participation by two- to threefold (OR: range 2.3 to 2.9). Older people were three times less likely to report a severe concern in the emotional well-being domain (OR 0.35; CI: 0.13 to 0.95). Having AMD more than doubled the odds of moderate and severe restrictions in the reading and accessing information domain (table 3). Duration of vision impairment, cause of vision impairment (other than AMD), language, receiving help with chores and having co-morbidity were not found to be associated with total or domain scores. Interestingly, it was the effect of co-morbidity rather than having co-morbidity per se that generated associations.

DISCUSSION This study highlights three characteristics that clinicians can use to identify patients in need of low vision rehabilitation, namely presenting visual acuity, the impact of co-morbidity on daily 254

activities and being in receipt of meals from family and friends. Of these, the strongest independent predictor was visual acuity. This is consistent with the findings of previous studies.17–20 Accordingly, those patients who presented with moderate or severe vision loss had a greater likelihood of needing to be referred to rehabilitation services. This is not to suggest that patients in the mild visual acuity category are exempt from referral consideration. Indeed, previous research has shown that those with visual acuity of ,6/12 can experience difficulties in activities of daily living, having a greater risk of falls, hip fracture and depression.17–24 We, therefore, argue that visual acuity is the main characteristic that should alert clinicians to possible rehabilitation needs and recommend a change in the common practice of deferring referrals until vision has deteriorated to severe levels.7 Increased dependence and impact of co-morbidities on participation are also useful indicators for rehabilitation needs. Br J Ophthalmol 2008;92:252–255. doi:10.1136/bjo.2007.125955


Clinical science Another key finding of this study was that patients were not homogeneous in terms of their rehabilitation needs. Our domainlevel analyses indicated that those with AMD were more likely to need assistance with reading and accessing information issues. As a result, clinical or optical intervention may be required, and many would benefit from prescription and training in the use of optical or non-optical devices. Patients who report difficulties on the emotional well-being domain may require counselling intervention because depression can interact with vision impairment to increase the adverse effects of both conditions.24 Our study shows that younger age groups may be in particular need of counselling. Likewise, those experiencing difficulties in the mobility and independence domains, particularly females, are likely to benefit from orientation and mobility services. Patients with difficulties spanning multiple domains are likely to require the services of a multidisciplinary low vision service team. The key message from a rehabilitation perspective is that service provision needs to be tailored to the specific needs of individual patients. One of the enduring challenges that clinicians face is their patients’ perception of need. Our earlier research found that some patients with low vision do not consider intervention necessary;25 nor do they use all the services available in a multidisciplinary service.17 As a result, the task of assessing patients for referral to low vision rehabilitation is not always simple or easily definable in terms of an externally imposed criterion of need versus no need based only on visual acuity. Rather, assessments need to be patient-specific, establishing the patient’s own felt need and recognising the domainspecific interventions that individuals may benefit from.

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CONCLUSION

18.

Our study not only confirms earlier findings regarding the importance of visual acuity as a trigger for referral but also highlights the need for clinicians to additionally consider issues relating to dependency to identify restrictions in participation and, hence, rehabilitation needs for people with low vision. A more holistic approach to patient referral and rehabilitation provision is therefore warranted. Acknowledgements: This work was supported by the Australian Government Cooperative Research Centre Program, Vision Australia, VicHealth, Jack Brockhoff Foundation, Lions Clubs of Victoria, National Health and Medical Research Council (NHMRC) Public Health Fellowship (ELL), Royal Victorian Eye and Ear Hospital Wagstaff Fellowship (JEK) and The Ian Potter Foundation (PMO’C). Competing interests: None.

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