Vision-related Activity Limitation Research Articles

Measurement of visual functioning following first and second eye cataract surgery using Vision-Related Activity Limitation Item Bank.

This study aims to compare visual functioning (VF) after first or second eye cataract surgery using the vision-related activity limitation (VRAL) item bank. This prospective, interventional study included 787 patients (mean age, 58.2 years) with cataract undergoing cataract surgery (first eye surgery with/out ocular comorbidity, second eye surgery with/out ocular comorbidity) at a tertiary eye care center, South India, who were administered the item bank pre- and at 6 weeks postoperatively to assess change in VF. Rasch analysis was used to estimate VF at both time points, and responsiveness to cataract surgery was calculated as effect size (ES) which was interpreted as small (≤ 0.2), moderate (0.3-0.7), and large (≥ 0.8). Mean best-corrected logMAR VA in surgical eye improved significantly postoperatively compared to preoperative VA (0.20 ± 0.40 vs. 1.19 ± 0.96; P < 0.0001) across all groups. Patients reported significant and large improvements in VF postoperatively across all groups: largest ES for first eye surgery without comorbidity (1.87 [95% CI, 1.61, 2.13]) and smallest for second eye without ocular comorbidity (1.55 [95% CI, 1.22, 1.88]). Compared to patients undergoing second eye surgery, first eye surgery patients reported significantly lower VF preoperatively (-0.72 ± 2.39 vs. 0.17 ± 2.34 logits; P < 0.0001), and a larger change in VF postoperatively (3.71 ± 2.33 logits vs. 4.27 ± 2.83 vs.; P = 0.004). Cataract surgery resulted in large and significant improvements in VF, regardless of ocular comorbidity and first or second eye surgery. The VRAL item bank is a useful tool to measure responsiveness to cataract surgery.

Psychometric Validity of the Visual Function Index in Leber Hereditary Optic Neuropathy.

The purpose of this study was to determine the psychometric validity of the Visual Function Index (VF-14) for use by patients with Leber hereditary optic neuropathy (LHON). Rasch analysis was conducted in two stages using data for 196 individuals (74.5% male) carrying one of the three primary LHON mutations and affected by vision loss. In stage 1, scale unidimensionality, scale-to-sample targeting, response category threshold ordering, item fit statistics, local dependency, and reliability were assessed. In stage 2, iterative post-hoc revisions of the VF-14 structure (VF-14R) were applied and psychometrically re-evaluated. Issues identified with the VF-14 included disordered response thresholds (12/14 items), local dependency (10/91 pairwise dependencies), and evidence of multidimensionality. However, the distribution of person estimates and item thresholds were fairly well matched, only one item showed misfit to the Rasch model, and there was good reliability (Person Separation Index 0.84). Rasch-informed VF-14 revisions included removing both driving items and the misfitting sports item, rescoring response options across all items by merging two response categories, and accounting for the dependency between two reading items. The VF-14R demonstrated improved psychometric validity. Clinicians and researchers using the VF-14 with LHON patients should be aware of its limitations. Compared to the original version, the proposed Rasch-based structure of the VF-14R appears to offer improved psychometric performance and interpretation of vision-related activity limitation. The original version of the VF-14 exhibits several limitations that undermines its psychometric validity as a patient-reported outcome measure for patients with LHON.

Change in rehabilitation needs and activity limitations over time of adults with acquired visual impairment following entry to a low vision rehabilitation service in England.

Longitudinal changes in priority rehabilitation needs, vision-related activity limitation and importance of visual goals were evaluated in a sample of people with a visual impairment over a year following entry to low vision rehabilitation services in England. Participants were adults with newly registered visual impairment within Leicestershire. Priority scores, indicating the level of rehabilitative need, were determined from the importance and difficulty scores of the 48goals of the Participation and Activity Inventory (PAI). Rasch analysis of the difficulty and importance scores examined activity limitation and importance separately. PAI outcome measures were assessed on entry to rehabilitation services and at 4 and 12months thereafter. Forty-eight participants (mean age 74.2, SD 14.1years) completed three visits. Overall, there was a statistically significant reduction in the perceived need for rehabilitation over time (p<0.001, ηp2 =0.29), driven by reduced perceived difficulty (p<0.001, ηp2 =0.32) but stable importance (p=0.73) of goals, with most change occurring between baseline and 4months. PAI goals with greatest rehabilitative need at study entry were reading, mobility and writing, and these remained of highest priority over time. The greatest priority score decrease was for the goal 'Hobbies and crafts'. The largest decrease in importance was for 'Mobility outdoors', whereas 'Relationship with loved ones' increased most. Despite a decline in the perceived need for rehabilitation over the study period, there remains a need for continued support and intervention at 12months following registration with rehabilitation services, particularly for the key goals of reading, writing and mobility. Early identification and support for individuals' important but difficult goals could prevent such goals being relinquished. Goals concerning relationships and communication became more important over time, indicating that re-evaluation of needs at follow-up is necessary to inform ongoing service provision.

Impact of moderate and severe primary open-angle glaucoma on quality of life due to activity limitation.

Purpose:To study the impact of moderate and severe primary open-angle glaucoma (POAG) on the quality of life (QoL) due to activity limitation using glaucoma-specific questionnaires.Methods:This cross-sectional study enrolled 122 participants, 50% (n = 61) being controls and 50% were diagnosed cases of moderate/severe POAG. Three orally administered glaucoma-specific QoL instruments were used: Glaucoma Activity Limitation (GAL-9), Glaucoma Quality of Life (GQL-15), and Viswanathan questionnaires. The questions related to activity limitation were identified and analyzed for each questionnaire separately.Results:The mean age of the participants was 61.04 ± 9.88 years and a majority were males (64.8%, n = 79). The mean scores in controls, moderate glaucoma, and severe POAG patients for GAL-9 questionnaire were 9.77 ± 1.36 (P = 0.44), 13.75 ± 4.76 (P < 0.001), and 23.45 ± 5.62 (P < 0.001), for GQL-15, these were 16.39 ± 2.18 (P = 0.5), 22.75 ± 7.89 (P < 0.001), and 39.34 ± 9.42 (P < 0.001), respectively, while for the Viswanathan questionnaire, they were 9.49 ± 0.94 (P = 0.38), 7.91 ± 1.59 (P < 0.001), and 4.41 ± 2.20 (P < 0.001), respectively. The GQL-15 and GAL-9 questionnaires concluded that activity limitation pertaining to dark adaptation-related tasks affected the QoL the most in moderate as well as severe POAG (P < 0.001). Using the Viswanathan questionnaire, it was observed that the peripheral vision-related activity limitation was most significant for the decrease in QoL in moderate POAG while near vision-related activity limitation affected the QoL the most in severe POAG (P < 0.001).Conclusion:All three questionnaires concluded that the activity limitation due to moderate and severe glaucoma has a negative impact on the QoL. The limitation of the tasks involving dark adaptation/glare and peripheral vision has the most significant impact on the QoL in moderate glaucoma. As the disease progresses to a severe category, the limitation of activities requiring central and near vision causes the most significant worsening in QoL.

Psychometric Properties of an Indian Translation of the Vision-related Activity Limitation Item Bank in Cataract.

The Indian translated and culturally adapted version of the vision-related activity limitation (VRAL) item bank is a validated instrument to assess the difficulty in performing daily activities by cataract patients and can also be used to capture self-reported changes in ability to perform daily activities after cataract surgery. The purpose of this study was to document (a) translation, cross-cultural adaptation of VRAL item bank into an Indian language, and (b) its validation using Rasch analysis in a South Indian cataract population. At the first stage, a translated Indian version of VRAL item bank was produced using recommended procedures. At the second stage, Rasch analysis was performed to investigate its psychometric properties in 787 cataract patients (mean age, 58.2 years; mean ± SD visual acuity [logMAR], 1.19 ± 0.96 at baseline in eye for surgery) including comparison with the original version. Post-translation equivalence of meaning was achieved, but some English phrases required cross-cultural adaptation. Subsequently, all items were appropriate for the Indian culture, and VRAL item bank demonstrated excellent measurement precision (7.39). Dimensionality assessment suggested that VRAL construct may contain other dimensions such as self-care and visual search, and mobility. Self-care and visual search formed a unidimensional measure but was highly correlated with main VRAL dimension, and the removal of its items weakened precision of the main VRAL dimension measurement. Taken together, evidence favored retaining self-care and visual search items in a larger VRAL item bank. Mobility subscale lacked adequate measurement precision, so it was not examined further; again, items were retained in VRAL scale because they strengthened its measurement properties. Majority of items (99%) did not demonstrate notable differential item functioning (>1.0 logit) by presenting visual acuity (median, 0.20 logMAR) in the better-seeing eye. Items in the translated Indian VRAL item bank measure the same construct as the English version and fulfilled the psychometric requirements for use in cataract patients.

Spectacle use after routine cataract surgery and vision-related activity limitation.

To explore the relationship between acquisition of new spectacles after routine cataract surgery and vision-related activity limitation (VRAL) postoperatively. This cohort study with intervention (survey) included 1329 patients in Sweden who had undergone a second-eye cataract surgery during March 2013. Data from the Swedish National Cataract Register were used, including evaluations of VRAL through the Catquest-9SF questionnaire before and 3months after cataract surgery. Five months after the second-eye surgery, patients completed another five-item questionnaire about spectacle use preoperatively and postoperatively including an item on surgeons' advice about the need for spectacles. These responses were linked to the Rasch-analysed Catquest-9SF data to identify correlations with VRAL. A total of 1239 patients finally participated in the study after excluding those who did not fulfil the inclusion criteria. Patients who were advised about the need for spectacles postoperatively (n=387) had a greater (p=0.039) improvement in the postoperative VRAL compared to patients who were not advised (n=691). Patients who obtained new spectacles postoperatively (n=512) also had greater improvement (p=0.032) compared to those who did not (n=724). The average improvements in the VRAL after surgery were significantly higher for patients who obtained new distance spectacles postoperatively and for patients who were informed about the need for spectacles by their practitioners.

Impact of age-related macular degeneration in patients with glaucoma: understanding the patients' perspective.

The aim of the study is to measure the impact of age-related macular degeneration on vision-related activity limitation and preference-based status for glaucoma patients. This was a cross-sectional study. Two-hundred glaucoma patients of whom 73 had age-related macular degeneration were included in the research. Sociodemographic information, visual field parameters and visual acuity were collected. Age-related macular degeneration was scored using the Age-Related Eye Disease Study system. The Rasch-analysed Glaucoma Activity Limitation-9 and the Visual Function Questionnaire Utility Index measured vision-related activity limitation and preference-based status, respectively. Regression models determined factors predictive of vision-related activity limitation and preference-based status. Differential item functioning compared Glaucoma Activity Limitation-9 item difficulty for those with and without age-related macular degeneration. Mean age was 73.7 (±10.1) years. Lower better eye mean deviation (β: 1.42, 95% confidence interval: 1.24-1.63, P < 0.001) and age-related macular degeneration (β: 1.26 95% confidence interval: 1.10-1.44, P = 0.001) were independently associated with worse vision-related activity limitation. Worse eye visual acuity (β: 0.978, 95% confidence interval: 0.961-0.996, P = 0.018), high risk age-related macular degeneration (β: 0.981, 95% confidence interval: 0.965-0.998, P = 0.028) and severe glaucoma (β: 0.982, 95% confidence interval: 0.966-0.998, P = 0.032) were independently associated with worse preference-based status. Glaucoma patients with age-related macular degeneration found using stairs, walking on uneven ground and judging distances of foot to step/curb significantly more difficult than those without age-related macular degeneration. Vision-related activity limitation and preference-based status are negatively impacted by severe glaucoma and age-related macular degeneration. Patients with both conditions perceive increased difficulty walking safely compared with patients with glaucoma alone.

Refractive error and vision-related quality of life in South Indian children.

To understand the vision-related quality of life (QoL) of schoolchildren with uncorrected refractive error (URE). A snapshot qualitative research design and homogeneous sampling strategy was adopted. Thirty-one, 27, and 22 eye care practitioners, children, and teachers participated in four, three, and two focus group discussions, respectively. The participants were recruited from various parts of Chennai, India. The discussions were audio recorded, transcribed, coded, and analyzed. Eight themes emerged: complaints and symptoms of children with URE, vision-related activity limitation, coping strategies, psychological impact, social impact, the perceived difference after first time refractive correction, reasons for refractive error remaining uncorrected, and the significant amount of refractive error. The study gives a holistic view of the vision-related QoL of children with URE by demonstrating the difficulties and problems that they face in their day-to-day life and also by describing the perceived difference in QoL after wearing refractive correction.

Impact of bilateral cataract surgery on vision-related activity limitations

To evaluate patients' vision-related activity limitation before and after bilateral cataract surgery using the German version of the Catquest-9SF questionnaire. Hanusch Hospital, Vienna, Austria, and Ophthalmic Clinic, Minden, Germany. Questionnaire development. This prospective 2-center study included patients who were scheduled for bilateral cataract surgery and attended their preassessment appointment approximately 1 week before cataract surgery. All patients self-administered the Catquest-9SF at the preassessment session and a second time 3 months after cataract surgery. The questionnaire includes 9 items and is a revised short form of the Catquest, scored using Rasch analysis. The Catquest-9SF includes questions concerning vision-associated problems in everyday life, general satisfaction with vision, and difficulties performing activities. The study comprised 210 patients, 120 in Austria and 90 in Germany. The mean age of all patients was 74.1 years (range 41 to 92 years). Patients mostly had difficulties doing handwork (42%) or recognizing uneven surfaces (30%). Sixty percent of the patients in Austria and approximately 50% in Germany were very unsatisfied with their vision preoperatively. Postoperatively, all patients recognized a subjective improvement in their vision. Patients having bilateral cataract surgery achieved marked improvements in vision-related activity limitation and satisfaction with vision. A subset of patients with less vision-related activity limitation before surgery was satisfied with first-eye surgery only.

Adjustment to Vision Loss in a Mixed Sample of Adults with Established Visual Impairment

To determine factors associated with the level of adjustment to vision loss in a cross-sectional sample of adults with mixed visual impairment. One hundred participants were administered the Acceptance and Self-Worth Adjustment Scale (AS-WAS) to assess adjustment to vision loss. The severity of vision loss was determined using binocular clinical visual function assessments including visual acuity, contrast sensitivity, reading performance, and visual fields. Key demographics including age, duration of visual impairment, general health, education, and living arrangements were evaluated, as were self-reported vision-related activity limitation (VRAL), depression, social support, and personality. Multivariate analysis showed that higher levels of depressive symptoms (β = -0.26, P < 0.01) and of the personality trait neuroticism (β = -0.33, P < 0.001), and lower levels of the personality trait of conscientiousness (β = 0.29, P < 0.01), were associated with poorer adjustment to vision loss, explaining 56% variance. Adjustment to vision loss is significantly associated with depression and certain traits of personality (specifically neuroticism and conscientiousness), independent of the severity of vision loss, VRAL, and duration of vision loss. The results suggest certain individuals may be predisposed to exhibiting less adjustment to vision loss due to personality characteristics, and exhibit poorer adjustment owing to or as a consequence of depression, rather than due to other factors such as the onset and severity of visual impairment.

The Importance of Rating Scale Design in the Measurement of Patient-Reported Outcomes Using Questionnaires or Item Banks

To investigate the effect of rating scale designs (question formats and response categories) on item difficulty calibrations and assess the impact that rating scale differences have on overall vision-related activity limitation (VRAL) scores. Sixteen existing patient-reported outcome instruments (PROs) suitable for cataract assessment, with different rating scales, were self-administered by patients on a cataract surgery waiting list. A total of 226 VRAL items from these PROs in their native rating scales were included in an item bank and calibrated using Rasch analysis. Fifteen item/content areas (e.g., reading newspapers) appearing in at least three different PROs were identified. Within each content area, item calibrations were compared and their range calculated. Similarly, five PROs having at least three items in common with the Visual Function (VF-14) were compared in terms of average item measures. A total of 614 patients (mean age ± SD, 74.1 ± 9.4 years) participated. Items with the same content varied in their calibration by as much as two logits; "reading the small print" had the largest range (1.99 logits) followed by "watching TV" (1.60). Compared with the VF-14 (0.00 logits), the rating scale of the Visual Disability Assessment (1.13 logits) produced the most difficult items and the Cataract Symptom Scale (0.24 logits) produced the least difficult items. The VRAL item bank was suboptimally targeted to the ability level of the participants (2.00 logits). Rating scale designs have a significant effect on item calibrations. Therefore, constructing item banks from existing items in their native formats carries risks to face validity and transmission of problems inherent in existing instruments, such as poor targeting.

The impact of diabetic retinopathy on quality of life: qualitative findings from an item bank development project

Assessing the efficacy of treatment modalities for diabetic retinopathy (DR) from the patient's perspective is restricted due to a lack of a comprehensive patient-reported outcome measure. We are developing a DR-specific quality of life (QoL) item bank, and we report here on the qualitative results from the first phase of this project. Eight focus groups and 18 semi-structured interviews were conducted with 57 patients with DR. The sessions were transcribed verbatim and iteratively analysed using the constant comparative method and NVIVO software. Participants had a median age of 58 years (range 27-83 years). Twenty-seven (47%) participants had proliferative DR in the better eye, and 14 (25%) had clinically significant macular oedema. Nine QoL domains were identified, namely visual symptoms, ocular surface symptoms, vision-related activity limitation, mobility, emotional well-being, health concerns, convenience, social, and economic. Participants described many vision-related activity limitations, particularly under challenging lighting conditions; however, socioemotional issues were equally important. Participants felt frustrated due to their visual restrictions, concerned about further vision loss and had difficulty coping with this uncertainty. Restrictions on driving were pervasive, affecting transport, social life, relationships, responsibilities, work and independence. Patients with DR experience many socioemotional issues in addition to vision-related activity limitations. Data from this study will be used to generate data for a DR-specific QoL item bank.

Reengineering the Glaucoma Quality of Life-15 Questionnaire with Rasch Analysis

To investigate, using Rasch analysis, whether the 15-item Glaucoma Quality of Life-15 (GQL-15) forms a valid scale and to optimize its psychometric properties. One hundred eighteen glaucoma patients (mean age, 65.7 years) completed the German-version of the GQL-15. Rasch analysis was performed to assess category function (how respondents differentiated between the response options), measurement precision (discriminative ability), unidimensionality (whether items measure a single construct), targeting (whether items are of appropriate difficulty for the sample), and differential item functioning (whether comparable subgroups respond differently to an individual item). Where any of these attributes were outside acceptable ranges, steps were taken to improve the instrument. The five-response categories of the GQL-15 were well differentiated by respondents, as demonstrated by ordered and well-spaced category thresholds. The GQL-15 had an excellent measurement precision but demonstrated poor targeting of item difficulty to person ability and multidimensionality, indicating that it was measuring more than one construct. Removal of six misfitting items created a nine-item unidimensional instrument with good measurement precision and no differential item functioning but poor targeting. A new name, the Glaucoma Activity Limitation (GAL-9) questionnaire, is proposed for the short version, which better reflects the construct under measurement. The GAL-9 has superior psychometric properties over the GQL-15. Its only limitation is poor targeting of item difficulty to person ability, which is an inevitable attribute of a vision-related activity limitation instrument for glaucoma patients, most of whom have only peripheral visual field defects and little difficulty with daily activities.

Factors Influencing Self-reported Vision-Related Activity Limitation in the Visually Impaired

The use of patient-reported outcome (PRO) measures to assess self-reported difficulty in visual activities is common in patients with impaired vision. This study determines the visual and psychosocial factors influencing patients' responses to self-report measures, to aid in understanding what is being measured. One hundred visually impaired participants completed the Activity Inventory (AI), which assesses self-reported, vision-related activity limitation (VRAL) in the task domains of reading, mobility, visual information, and visual motor tasks. Participants also completed clinical tests of visual function (distance visual acuity and near reading performance both with and without low vision aids [LVAs], contrast sensitivity, visual fields, and depth discrimination), and questionnaires assessing depressive symptoms, social support, adjustment to visual loss, and personality. Multiple regression analyses identified that an acuity measure (distance or near), and, to a lesser extent, near reading performance without LVAs, visual fields, and contrast sensitivity best explained self-reported VRAL (28%-50% variance explained). Significant psychosocial correlates were depression and adjustment, explaining an additional 6% to 19% unique variance. Dependent on task domain, the parameters assessed explained 59% to 71% of the variance in self-reported VRAL. Visual function, most notably acuity without LVAs, is the best predictor of self-reported VRAL assessed by the AI. Depression and adjustment to visual loss also significantly influence self-reported VRAL, largely independent of the severity of visual loss and most notably in the less vision-specific tasks. The results suggest that rehabilitation strategies addressing depression and adjustment could improve perceived visual disability.

Item Banking: A Generational Change in Patient-Reported Outcome Measurement

Patient-reported outcomes are traditionally measured with questionnaires and many have been developed to measure Vision-Related Activity Limitation (VRAL; visual disability or visual functioning), Symptoms, and Quality Of Life (QOL). These vary in quality and can be classified as First or Second Generation instruments. First generation instruments are characterized by simple summary scoring of ordinal responses, which precludes interval measurement. This problem is solved in second generation instruments where Rasch analysis is used to optimize psychometric properties. However, second generation instruments retain limitations; difficulties in comparing scores across instruments, limited applicability to populations and inability to adapt to change. A third generation approach to patient-reported outcomes measurement, item banking, can solve these problems. The aim of this project was to use Rasch analysis to calibrate all items from all instruments to form VRAL, Symptoms, and QOL Item Banks. Six hundred twenty-four people on the waiting list for cataract surgery were recruited. Each participant completed, by self-administration, a number of the 19 instruments. A total of 353 items were calibrated using Rasch analysis (Winsteps v3.67). The psychometric properties of each item bank were optimized; items fitting the Rasch model were retained (Infit and Outfit range, 0.50 to 1.50). Items were sorted into the three traits; 226 tapped VRAL, 22 symptoms, and 60 QOL. Satisfactory measurement of each latent trait occurred with person separation of 8.11 for VRAL, 2.33 for Symptoms, and 3.20 for QOL. Rasch estimates of item difficulty were highly stable with an average standard error of 0.11 logits. Item banks for the measurement of the latent traits of VRAL, symptoms, and QOL have been formed. New items can be added to enable evolution of measurement. Item banking facilitates accurate and precise measurement through computer adaptive testing. This approach provides common measurement scales, facilitating worldwide comparison of results.