Outcomes Of Low Vision Rehabilitation Research Articles

Concept Mapping to Identify Content for a Performance-Based Measure of Low Luminance Vision-Related Activities of Daily Living.

PurposeThe purpose of this study was to identify low luminance activities of daily living (ADL) relevant to adults with vision impairment using a concept-mapping approach.Methods“Group concept mapping” was utilized to identify specific ADLs that persons with vision impairment find challenging under low light conditions. In the first “brainstorming” phase, 24 adults with vision impairment from a range of eye conditions (mean age = 73 years, SD = 14 years) and 26 international low vision experts (mean experience = 22, SD = 11 years) generated statements to the focus prompt, “Thinking as broadly as possible, generate a list of statements detailing specific day-to-day activities a person with vision impairment might find challenging under low light conditions, such as in a poorly lit room or outside at dusk.” In the second phase, participants sorted activities by similarity and rated the importance of each activity. Multidimensional scaling and hierarchical cluster analysis were applied to produce concept maps showing clusters of prioritized activities.ResultsOne hundred thirteen unique ideas/activities were generated, rated and sorted. Eight clusters were identified (from highest to lowest importance): hazard detection and safety outside; social interactions; navigation; near reading; selfcare and safety at home; distance spotting; searching around the home; and cooking and cleaning.ConclusionsThe conceptual framework and low luminance ADLs identified (the most important being hazard detection and safety outside, and social interactions) provide a basis for developing a performance-based measure of low luminance visual function.Translational RelevanceA performance-based measure of low luminance vision-related ADLs is required for comprehensively and objectively assessing efficacy of eye treatments and low vision rehabilitation outcomes in adults with vision impairment.

Reliability and validity of the Canadian–French ecological adaptation of the weighted version of the Melbourne low-vision ADL Index

Background: The Mesure de l’impact de la déficience visuelle dans les activités quotidiennes (MIDVAQ) is the Canadian–French adaptation of the Melbourne Low-Vision ADL Index. It measures performance, personal importance and handicap situation in 16 instrumental activities requiring near vision (standardized material, part A) and in 9 self-care and domestic activities (self-report questionnaire, part B). This study aimed at measuring the MIDVAQ reliability and its relationship with measures of visual functions and functional vision.Methods: The MIDVAQ was administered twice to 100 visually impaired participants, at home, with their personal visual and non-visual aid. A second rater was present at T1. Two different versions of part A were used alternately at T1 and T2.Results: The total Handicap scale demonstrates good internal reliability (Cronbach’s alpha coefficient = 0.82) and very high inter-rater and test-retest reliability (ICCs = 1.00 and 0.86). Part A alternative versions are highly comparable. Vision function measures are significantly correlated with total Handicap score, for which 48% of the variance is explained by functional vision estimates, age, and education.Conclusions: The MIDVAQ is highly valid and reliable. It can be useful to measure the functional impact of the visual impairment, its progression, and the outcomes of low vision rehabilitation services.Implications for rehabilitationEven if administered at home in an ecological way, this measure of the impact of the visual impairment in daily activities is very reliable.Given its good metric properties, this tool can be confidently used to assess the functional impact of visual impairment, outcomes of the low vision rehabilitation services, etc.This measurement tool provides complementary information to those obtained from clinical measures of visual functions, by reflecting the interaction between the functional abilities with the requirements of the environment.

Clinical outcomes of low vision rehabilitation delivered by a mobile clinic.

This prospective cohort study examined clinical outcomes of low vision rehabilitation (LVR) delivered by a mobile clinic. Participants were recruited from those scheduled for mobile clinic LVR and met the United States definition of legal blindness. Participants completed the Massof Activity Inventory (AI) before LVR, 3months post-LVR, and 1year post-LVR. Change scores and measures of clinical effect (i.e. Cohen's effect size and minimum clinically important difference, MCID) were calculated for each time point and compared. Additional participant characteristics (age, acuity, contrast sensitivity, cause of visual impairment, training recommendations, and prior LVR experience) were also explored with respect to outcome measures. Of the 66 participants enroled in this study, 47% had no prior LVR experience. Significant differences were noted between baseline and 3-month person measures, and between baseline and 1-year person measures. There was no significant difference between 3-month and 1-year person measures, nor was there a significant difference in change score between these two time points. At 1year post-LVR, overall visual ability effect size was 0.74. A clinically meaningful outcome was achieved in 56% of participants at 3months and 71% at 1year for overall visual ability. There was no significant difference in the proportion of participants achieving MCID at 3months vs 1year. Of participants who completed the 1-year post-LVR AI, 59% reported a subjective worsening of vision during the study period. This subgroup also tended to have smaller 1-year change scores. Mobile clinic LVR is effective at expanding access to care and produces clinically meaningful outcomes comparable to those seen in other outpatient LVR delivery models.

Assessing the effectiveness of low vision rehabilitation in children: an observational study.

To evaluate the change in visual functioning (VF) using the L. V. Prasad-Functional Vision Questionnaire II (LVP-FVQ II) following multidisciplinary low vision rehabilitation (LVR) services in children with low vision (LV). Children with LV referred for the first time to the Centre for Sight Enhancement were administered the LVP-FVQ II at baseline and at 3 to 4 months' follow-up to assess the outcomes of LVR. Participants' responses to the LVP-FVQ II at baseline and follow-up were transformed into interval-level estimates of VF using Rasch analysis. Cohen's d values (effect size) were used to estimate the magnitude of change in VF. A total of 183 participants completed the rehabilitation (mean age, 11.9 years; male, 57%). More than one-half of the participants had retinal disorders (55%) and most were moderately visually impaired (<20/60-20/200, 76.5%). Using the LVP-FVQ II, significant improvement in VF after rehabilitation was recorded (P < 0.0001) and the increase in VF (SD) was 1.20 (1.82) logits. Using Cohen's d, the magnitude of the improvement in LVR intervention at follow-up was found to be 0.75, indicating nearly large treatment effect. Ours is the first study to provide strong evidence that LVR services result in nearly large and significant improvements in the overall VF in children with LV, regardless of the cause of LV. These results should encourage eye care professionals to refer children with LV to LVR services. Further investigation is needed to determine if the improvement in VF can be sustained over a longer duration (>4 months).

Visual ability of patients seeking outpatient low vision services in the United States.

Most patients with low vision are elderly and have functional limitations from other health problems that could add to the functional limitations caused by their visual impairments. To identify factors that contribute to visual ability measures in patients who present for outpatient low vision rehabilitation (LVR) services. As part of a prospective, observational study of new patients seeking outpatient LVR, 779 patients from 28 clinical centers in the United States were enrolled in the Low Vision Rehabilitation Outcomes Study (LVROS) from April 25, 2008, through May 2, 2011. The Activity Inventory (AI), an adaptive visual function questionnaire, was administered to measure overall visual ability and visual ability in 4 functional domains (reading, mobility, visual motor function, and visual information processing) at baseline before LVR. The Geriatric Depression Scale, Telephone Interview for Cognitive Status, and Medical Outcomes Study 36-Item Short-Form Health Survey physical functioning questionnaires were also administered to measure patients' psychological, cognitive, and physical health states, respectively. Predictors of visual ability and functional domains as measured by the AI. Among the 779 patients in the LVROS sample, the mean age was 76.4 years, 33% were male, and the median logMAR visual acuity score was 0.60 (0.40-0.90 interquartile range). Correlations were observed between logMAR visual acuity and baseline visual ability overall (r = -0.42) and for all functional domains. Visual acuity was the strongest predictor of visual ability (P < .001) and reading ability (P < .001) and had a significant independent effect on the other functional domains. Physical ability was independently associated with (P < .001) overall visual ability as well as mobility and visual motor function. Depression had a consistent independent effect (P < .001) on overall visual ability and on all functional domains, whereas cognition had an effect on only reading and mobility (P < .001). Visual ability is a multidimensional construct, with visual acuity, depression, physical ability, and cognition explaining more than one-third of the variance in visual ability as measured by the AI. The significant contributions of the nonvisual factors to visual ability measures and the rehabilitation potential (ie, ceiling) effects they may impose on LVR are important considerations when measuring baseline visual ability and ultimately LVR outcomes in ongoing clinical research.

Comparison of Clinician-Predicted to Measured Low Vision Outcomes

To compare low-vision rehabilitation (LVR) clinicians' predictions of the probability of success of LVR with patients' self-reported outcomes after provision of usual outpatient LVR services and to determine if patients' traits influence clinician ratings. The Activity Inventory (AI), a self-report visual function questionnaire, was administered pre-and post-LVR to 316 low-vision patients served by 28 LVR centers that participated in a collaborative observational study. The physical component of the Short Form-36, Geriatric Depression Scale, and Telephone Interview for Cognitive Status were also administered pre-LVR to measure physical capability, depression, and cognitive status. After patient evaluation, 38 LVR clinicians estimated the probability of outcome success (POS) using their own criteria. The POS ratings and change in functional ability were used to assess the effects of patients' baseline traits on predicted outcomes. A regression analysis with a hierarchical random-effects model showed no relationship between LVR physician POS estimates and AI-based outcomes. In another analysis, kappa statistics were calculated to determine the probability of agreement between POS and AI-based outcomes for different outcome criteria. Across all comparisons, none of the kappa values were significantly different from 0, which indicates that the rate of agreement is equivalent to chance. In an exploratory analysis, hierarchical mixed-effects regression models show that POS ratings are associated with information about the patient's cognitive functioning and the combination of visual acuity and functional ability, as opposed to visual acuity or functional ability alone. Clinicians' predictions of LVR outcomes seem to be influenced by knowledge of patients' cognitive functioning and the combination of visual acuity and functional ability-information clinicians acquire from the patient's history and examination. However, clinicians' predictions do not agree with observed changes in functional ability from the patient's perspective; they are no better than chance.

A multilevel item response theory model was investigated for longitudinal vision-related quality-of-life data

Objective To investigate how a multilevel item response theory (IRT) model for longitudinal dependent data could provide average and individual quality-of-life outcomes of low-vision rehabilitation. Study Design and Setting In a nonrandomized longitudinal design, visually impaired older patients ( n = 296) were referred to multidisciplinary rehabilitation or to an optometric service. The five-dimensional Low Vision Quality of Life Questionnaire was administered at four time points. The IRT model was characterized by the graded response model for rating scales. Covariates were added to the model, mainly to correct for missing data. The invariance assumption across time points was investigated. Results Average and individual rehabilitation effects were estimated. For multidisciplinary rehabilitation, significant average deterioration was seen on three dimensions after 4.4 years. Many individuals in the optometric service group significantly improved on the “reading small print” dimension (18.5%); in both groups, many individuals significantly deteriorated on “visual (motor) skills” (22.2–30.0%). Invariance across time points could be assumed for all dimensions, except for “adjustment.” Gender, education, visual acuity, and health status were significantly associated with the outcome. Conclusion We present how a multilevel IRT model can be applied to describe longitudinal dependent vision-related quality-of-life data, while focusing on average and individual effects.

Quality of Life of Low-Vision Patients and Outcomes of Low-Vision Rehabilitation

The impact of low vision on self-reported quality of life and changes after low-vision intervention are investigated. Literature reports from 1990 to 2000 are reviewed. Low vision is associated with increased risk for depression and decreased functional status and quality of life. Decreased visual acuity, visual field loss, and occasional blurred vision are also associated with decreased quality of life. Improvements in both functional status and quality of life occur after low-vision service delivery. Self-reported quality of life is a significant outcome measure for low-vision rehabilitation. Questionnaires that are more sensitive to rehabilitation services provided as well as patient needs and goals are required to facilitate development of rehabilitation plans and to compare techniques, devices, and programs. Attention should be given to measurement properties, validity, and reliability of instruments used currently and in development of new instruments.

Evaluating the outcomes of low vision rehabilitation

The requirement for those providing healthcare to measure outcomes raises the fundamental question of how these should be measured. Both the scale of the low vision population and the different models of care proposed make it a pressing need to determine outcomes using valid and reliable measures. In this study we describe the development and piloting of a questionnaire designed to meet this requirement. The questionnaire was piloted on 56 subjects with age-related macular degeneration (ARMD). Test-retest reliability of the questionnaire was estimated using a further sample of 28 subjects with ARMD. Pilot testing confirmed the feasibility of administering the questionnaire to an elderly population with ARMD. A total of 87% of the sample reported using an LVA (65% on a daily basis), predominantly for a reading task. The number of tasks an LVA was used for, its frequency of use, length of continuous use and ease of use are significantly associated with the rating of an LVA as important/less important (P<0.0001), but the acuity achieved with the device is not significantly associated with rated importance (P=0.11), reinforcing doubt about the validity of visual function outcomes. The limitations of this pilot study and earlier case series in describing the outcomes of low vision care are discussed and a randomised controlled trial using a broad range of outcomes is proposed in order to fully describe the effectiveness of low vision rehabilitation and inform the debate about models of care.

Evaluating the outcomes of low vision rehabilitation.

The requirement for those providing healthcare to measure outcomes raises the fundamental question of how these should be measured. Both the scale of the low vision population and the different models of care proposed make it a pressing need to determine outcomes using valid and reliable measures. In this study we describe the development and piloting of a questionnaire designed to meet this requirement. The questionnaire was piloted on 56 subjects with age-related macular degeneration (ARMD). Test-retest reliability of the questionnaire was estimated using a further sample of 28 subjects with ARMD. Pilot testing confirmed the feasibility of administering the questionnaire to an elderly population with ARMD. A total of 87% of the sample reported using an LVA (65% on a daily basis), predominantly for a reading task. The number of tasks an LVA was used for, its frequency of use, length of continuous use and ease of use are significantly associated with the rating of an LVA as important/less important (P < 0.0001), but the acuity achieved with the device is not significantly associated with rated importance (P = 0.11), reinforcing doubt about the validity of visual function outcomes. The limitations of this pilot study and earlier case series in describing the outcomes of low vision care are discussed and a randomised controlled trial using a broad range of outcomes is proposed in order to fully describe the effectiveness of low vision rehabilitation and inform the debate about models of care.