Comparative effectiveness between two types of head-mounted magnification modes using a smartphone-based virtual display.

SIGNIFICANCE: This work shows the benefits of using two different magnification strategies to improve the reading ability of low-vision patients using a head-mounted technology. PURPOSE: The aim of this study was to conduct a comparative clinical trial evaluating the effectiveness of two magnification strategies in a head-mounted virtual reality display. METHODS: Eighty-eight eligible low-vision subjects were randomized into two arms: (1) the full-field magnification display or (2) the virtual bioptic telescope mode. Subjects completed baseline testing and received training on how to use the device properly and then took the device home for a 2- to 4-week intervention period. An adaptive rating scale questionnaire (Activity Inventory) was administered before and after the intervention (home trial) period to measure the effect of the system. A Simulator Sickness Questionnaire was also administered. Baseline and follow-up results were analyzed using Rasch analysis to assess overall effectiveness of each magnification mode for various functional domain categories. RESULTS: Both magnification modes showed a positive effect for reading, visual information, and the overall goals functional domain categories, with only reading reaching statistical significance after correction for multiple comparisons. However, there were no significant between-group differences between the two modes. The results of the Simulator Sickness Questionnaire showed that the magnification modes of the head-mounted display device were overall well tolerated among low-vision users. CONCLUSIONS: Both the full-field and virtual bioptic magnification strategies were effective in significantly improving functional vision outcomes for self-reported reading ability.

Application of Rasch Analysis to Timed Instrumental Activities of Daily Living in Low Vision: A Validation Study.

SIGNIFICANCE: This work validates Rasch analysis of a performance-based low vision outcome measure evaluated in patients' own homes to ensure real-world relevance. Inclusion of sources of variance from the patient's home environment in functional outcome measures introduced nonuniform variance in measurements but did not preclude estimation of valid measures. PURPOSE: This study aimed to validate Rasch analysis of a performance-based outcome measure with real-world relevance. METHODS: Low vision patients (N = 161) receiving services from an occupational therapist performed Timed Instrumental Activity of Daily Living (TIADL) tasks in their homes. Rasch analysis was applied to error count and performance time data. Internal validity was assessed with evaluations of the accuracy and precision of estimated measures. External validity was assessed by comparing TIADL measures with measures estimated from the Activity Inventory (i.e., from self-reported difficulty ratings). RESULTS: Task measures were well targeted to person measures estimated from task performance time but were poorly targeted for measures estimated from task performance errors, for which most task trials (72%) were performed without error at baseline. Error-based person measures had larger standard errors with a smaller pseudo- R2 than time-based person or task measures and error-based task measures. Person measure infits for time- and error-based estimates conformed to expected values. The linear regressions between time-based person and task measures and corresponding error-based estimates had slopes of approximately 0.5, an observation consistent with larger estimation error variance for error-based measures than for time-based measures. Time-based TIADL person measures ( x ) and Activity Inventory person measures (estimated from all items, y ) were colinear but weakly correlated ( R = 0.19). CONCLUSIONS: Functional ability measures estimated from performance times of instrumental activity of daily living tasks in patients' homes demonstrate good internal and external validity. The ceiling effect from the infrequency of task performance errors in our data set limits use of TIADL error data to measure rehabilitation outcomes.

Predictors of problems reported on the EQ-5D-3L dimensions among people with impaired vision in northern Portugal.

BACKGROUND: The EQ-5D index often fails to detect the effect of ophthalmic diseases and sight loss. Investigating predictors of individual EQ-5D health dimensions might reveal the underlying reasons. The aim of this study was to investigate predictors of health dimension ratings obtained with the EQ-5D-3L from participants with impaired vision representing a spectrum of eye diseases. METHODS: Observational cross-sectional study with participants recruited at four public hospitals in Portugal. Outpatients with visual acuity of 0.30 logMAR(6/12) or worse in the better-seeing eye were invited to participate. Participants completed two instruments: the EQ-5D-3L (measures participants' perceived health-related quality-of-life) and the Massof Activity Inventory (measures visual ability-ability to perform vision-related activities). This study used logistic regression models to identify factors associated with responses to the EQ-5D-3L. RESULTS: The study included 492 participants, mean age 63.4 years (range = 18-93), 50% females. The most common diagnosis was diabetic retinopathy (37%). The mean visual acuity in the better seeing eye was 0.65 logMAR (SD = 0.48) and the mean visual ability was 0.62 logits (SD = 2.04), the correlation between the two was r = - 0.511 (p < 0.001). Mobility and self-care were the health dimensions with the fewest problems (1% reported extreme problems), anxiety and depression the dimension with the most problems (24% reported extreme problems). ROC curve analysis showed that the EQ-5D index was a poor predictor of cases of vision impairment whilst visual ability given was a good predictor of cases of vision impairment. Visual ability was an independent predictor of the response for all dimensions, higher ability was always associated with a reduced odds of reporting problems. The odds of reporting problems were increased for females in 3 out of 5 dimensions. Comorbidities, visual acuity and age-category were predictors of the odds of reporting problems for one dimension each. CONCLUSIONS: The odds of reporting problems for the five health dimensions of the EQ-5D-3L were strongly influenced by the ability to perform vision-related activities (visual ability). The EQ-5D index showed poor performance at detecting vision impairment. These findings are informative and relevant for the clinic and for research evaluating the impact of eye diseases and disease treatments in ophthalmology.

Topical Review: Understanding Vision Impairment and Sports Performance through a Look at Paralympic Classification.

SIGNIFICANCE: To provide meaningful competition that is equitable for Paralympic athletes, classification systems are vital to determine which athletes are eligible to compete in adapted forms of sports and to group athletes for competition. Our discussion has important implications to inform how we should approach visual function assessment in sports performance. Sport participation positively benefits individuals with low vision. In particular, adapted sports exist to provide people with visual disabilities an avenue for participating in recreational activity. High-performance low-vision athletes can participate in Paralympic sports but need to be properly classified based on the severity of their vision impairment. The model for Paralympic classification was initiated by Sir Ludwig Guttmann in 1952 in a rehabilitation clinic for soldiers with spinal cord injuries. Today, the International Paralympic Committee mandates that international sports federations develop evidence-based sport-specific classification systems to ensure that eligible disabled athletes have an opportunity for meaningful competition. With the current classification system, only visual acuity and visual field measures are considered to determine an athlete's eligibility to compete, leaving room to expand our understanding of visual function requirements for individual sports. In this topical review, we discuss the origins of Paralympic sports, limitations of current classification methods, and requirements toward achieving evidence-based sport-specific evaluation systems.

Cognitive Impairment among Veterans in Outpatient Vision Rehabilitation.

SIGNIFICANCE: Outpatient vision rehabilitation improves function in veterans with vision impairment, but the prevalence of cognitive impairment and the degree to which it may affect rehabilitation outcomes in the Veterans Affairs system are unknown. PURPOSE: The purpose of this study was to determine the prevalence of cognitive impairment among veterans receiving outpatient vision rehabilitation in the Veterans Affairs system and compare the benefits of rehabilitation in veterans with and without cognitive impairment. METHODS: We conducted cognitive assessments and a nested longitudinal cohort study in veterans with eye disorders at two outpatient rehabilitation sites. Cognition was assessed with the Modified Telephone Interview for Cognitive Status administered in person. Eligible veterans and their companions in the longitudinal study responded to questions about the veteran's function at baseline and 90 days later. Visual function was measured with the 48-item Low Vision Visual Function Questionnaire (LV-VFQ-48) and items from the Activity Inventory. RESULTS: Of 291 veterans assessed (mean ± standard deviation age, 78.2 ± 12 years), 136 (46.7%) were cognitively intact (Modified Telephone Interview for Cognitive Status scores, ≥33), whereas 58 (19.9%) had borderline scores of 30 to 32, 82 (28.2%) had scores suggesting mild/moderate cognitive impairment (scores of 20 to 29), and 15 (5.2%) had scores suggesting severe cognitive impairment (score of <20). After 90 days, mean LV-VFQ-48 reading scores tended to improve in veterans with (n = 21) and without (n = 28) cognitive impairment. The magnitude of self-reported improvement in LV-VFQ-48 scores was greater among cognitively intact, compared with cognitively impaired, veterans (effect size, 0.56 for reading; 0.71 for visual motor). Veterans and companions reported similar 90-day reduction in difficulty with the veterans' top 3 Activity Inventory goals, regardless of cognitive status. CONCLUSIONS: Approximately one in three veterans referred to outpatient vision rehabilitation has detectable cognitive impairment, yet many still experience functional improvements. Future research should determine best practices to accommodate challenges associated with cognitive impairment in vision rehabilitation and to track clinically meaningful outcomes.

Changes in the Properties of the Preferred Retinal Locus with Eccentric Viewing Training.

SIGNIFICANCE: This study explores whether eccentric viewing training (EVT) changes the properties of the retinal area used for fixation in subjects with bilateral macular disease. The data presented demonstrate the feasibility of conducting a randomized controlled trial on EVT. PURPOSE: Patients with bilateral central scotomas adopt other retinal area(s) called preferred retinal locus to substitute the blind fovea. EVT is offered with the goal to improve functional vision by learning how to identify and use a more useful retinal area for fixation-a trained retinal locus-and/or to improve fixation stability with their existing preferred retinal locus. An observational study was conducted to determine whether patients change and adopt a new trained retinal locus location and/or if fixation stability improves after EVT. METHODS: Seventy-six patients with bilateral central scotomas received EVT from an experienced rehabilitation therapist. Retinal locations for repeated fixations and sizes of central scotomas of the better eye were recorded before and after EVT with a scanning laser ophthalmoscope. The position and area of the 95% confidence bivariate ellipse that defines the retinal area in which 95% of fixations occur were analyzed. RESULTS: We observed no significant difference between the size of the area of the fitted ellipses before (mean [SD], 26.4° [19.7°]) and after (mean [SD], 24.8° [20.9°]) EVT (P = .54). However, we observed a shift in the preferred retinal locus location after EVT (P < .0001). The mean (SD) shift in the position of the center of fixation after EVT was 7.5° (5.2°; range, 0.45 to 23°). This mean difference was larger than would be expected from average within-subject fixation stability. CONCLUSIONS: The location of the retinal area used for fixation changes after EVT. Fixation stability does not change after EVT. These preliminary data are yet to be confirmed with the use of a control group.

Veterans Affairs Low-vision Intervention Trial II: One-year Follow-up.

SIGNIFICANCE: One-year follow-up is recommended for patients with macular diseases to assess functional changes associated with disease progression and to modify low-vision (LV) treatment plans, if indicated. PURPOSE: The purpose of this study was to observe 255 patients with macular diseases who received LV rehabilitation (rehabilitation with a therapist) or basic LV services (LV devices dispensed without therapy) during Veterans Affairs Low-vision Intervention Trial II after the trial ended at 4 months until 1-year follow-up. METHODS: The primary outcome measure was visual ability measured with the 48-item Veterans Affairs Low-vision Visual Functioning Questionnaire. Mean visual ability scores for the treatment groups were compared from baseline to 4 months, 4 months to 1 year, and baseline to 1 year. Changes from baseline to 1 year were compared between the two groups. Predictors of changes in visual ability from 4 months to 1 year were assessed using linear regression. RESULTS: Both groups experienced significant improvement in all measures of visual ability from baseline to 1 year but lost visual reading ability during the observation period (LV rehabilitation group, -0.64 [1.2] logit; 95% confidence interval [CI], -0.84 to -0.44 logit; basic LV group, -0.63 [1.4] logit; 95% CI, -0.88 to -0.38 logit), and overall visual ability was lost in the LV rehabilitation group (-0.20 [0.8] logit; 95% CI, -0.34 to -0.06 logit). Loss of visual reading ability in both groups from 4 months to 1 year was predicted by reading ability scores at 4 months, loss of near visual acuity from 4 months to 1 year, and lower EuroQol-5D utility index scores; loss of overall visual ability in the LV rehabilitation group during the same time period was predicted by lower overall ability scores at 4 months. CONCLUSIONS: Visual ability significantly improved in all groups from baseline to 1 year. However, the loss of visual reading ability experienced by both groups from 4 months to 1 year reduced the benefit of the services provided.

Low Vision Enhancement with Head-mounted Video Display Systems: Are We There Yet?

SIGNIFICANCE: Head-mounted video display systems and image processing as a means of enhancing low vision are ideas that have been around for more than 20 years. Recent developments in virtual and augmented reality technology and software have opened up new research opportunities that will lead to benefits for low vision patients. Since the Visionics low vision enhancement system (LVES), the first head-mounted video display LVES, was engineered 20 years ago, various other devices have come and gone with a recent resurgence of the technology over the past few years. In this article, we discuss the history of the development of LVESs, describe the current state of available technology by outlining existing systems, and explore future innovation and research in this area. Although LVESs have now been around for more than two decades, there is still much that remains to be explored. With the growing popularity and availability of virtual reality and augmented reality technologies, we can now integrate these methods within low vision rehabilitation to conduct more research on customized contrast-enhancement strategies, image motion compensation, image-remapping strategies, and binocular disparity, all while incorporating eye-tracking capabilities. Future research should use this available technology and knowledge to learn more about the visual system in the low vision patient and extract this new information to create prescribable vision enhancement solutions for the visually impaired individual.

Comparing the Impact of Refractive and Nonrefractive Vision Loss on Functioning and Disability: The Salisbury Eye Evaluation.

PURPOSE: To compare the effects of uncorrected refractive error (URE) and nonrefractive visual impairment (VI) on performance and disability measures. DESIGN: Cross-sectional, population-based study. PARTICIPANTS: A total of 2469 individuals with binocular presenting visual acuity (PVA) of ≥ 20/80 who participated in the first round of the Salisbury Eye Evaluation study. METHODS: The URE was defined as binocular PVA of ≤ 20/30, improving to >20/30 with subjective refraction. The VI was defined as post-refraction binocular best-corrected visual acuity (BCVA) of ≤ 20/30. The visual acuity decrement due to VI was calculated as the difference between BCVA and 20/30, whereas visual acuity due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of (1) vision status (VI, URE, or normal vision) using the group with normal vision as reference and (2) a 1-line decrement in acuity due to VI or URE. MAIN OUTCOME MEASURES: Objective measures of visual function were obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual difficulty measured by the Activities of Daily Vision (ADV) scale. The ADV responses were analyzed using Rasch analysis to determine visual ability. RESULTS: Compared with individuals with normal vision, subjects with VI (n = 191) had significantly poorer objective and subjective visual functioning in all metrics examined (P < 0.05), whereas subjects with URE (n = 132) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation, and lower ADV scores (P < 0.05), but did not demonstrate slower stair climbing or descent speed. For all functional metrics evaluated, the impact of VI was greater than the impact of URE. The impact of a 1-line VA decrement due to VI was associated with greater deficits in mobility measures and driving cessation when compared with a 1-line VA decrement due to URE. CONCLUSIONS: Visual impairment is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and nonrefractive vision loss should be distinguished in studies evaluating visual disability and be understood to have differing consequences.

Equating Visual Function Scales to Facilitate Reporting of Medicare Functional G-Code Severity/Complexity Modifiers for Low-Vision Patients.

OBJECTIVE: To present a method of estimating and equating scales across functional assessment instruments that appropriately represents changes in a patient's functional ability and can be meaningfully mapped to changes in Medicare G-code severity modifiers. DESIGN: Previously published measures of patients' overall visual ability, estimated from low-vision patient responses to 7 different visual function rating scale questionnaires, are equated and mapped onto Medicare G-code severity modifiers. SETTING: Outpatient low-vision rehabilitation clinics. PARTICIPANTS: The analyses presented in this article were performed on raw or summarized low-vision patient ratings of visual function questionnaire (VFQ) items obtained from previously published research studies. INTERVENTIONS: Previously published visual ability measures from Rasch analysis of low-vision patient ratings of items in different VFQs (National Eye Institute Visual Functioning Questionnaire, Index of Visual Functioning, Activities of Daily Vision Scale, Visual Activities Questionnaire) were equated with the Activity Inventory (AI) scale. The 39 items in the Self-Report Assessment of Functional Visual Performance (SRAFVP) and the 48 items in the Veterans Affairs Low Vision Visual Functioning Questionnaire (VA LV VFQ) were paired with similar items in the AI in order to equate the scales. MAIN OUTCOME MEASURES: Tests using different observation methods and indicators cannot be directly compared on the same scale. All test results would have to be transformed to measures of the same functional ability variable on a common scale as described here, before a single measure could be estimated from the multiple measures. RESULTS: Bivariate regression analysis was performed to linearly transform the SRAFVP and VA LV VFQ item measures to the AI item measure scale. The nonlinear relationship between person measures of visual ability on a logit scale and item response raw scores was approximated with a logistic function, and the 2 regression coefficients were estimated for each of the 7 VFQs. These coefficients can be used with the logistic function to estimate functional ability on the same interval scale for each VFQ and for transforming raw VFQ responses to Medicare's G-code severity modifier categories. CONCLUSIONS: The principle of using equated interval scales allows for comparison across measurement instruments of low-vision functional status and outcomes, but can be applied to any area of rehabilitation.

Characterizing functional complaints in patients seeking outpatient low-vision services in the United States.

PURPOSE: To characterize functional complaints of new low-vision rehabilitation patients. DESIGN: Prospective observational study. PARTICIPANTS: The Low Vision Rehabilitation Outcomes Study recruited 819 patients between 2008 and 2011 from 28 clinical centers in the United States. METHODS: New patients referred for low-vision rehabilitation were asked, "What are your chief complaints about your vision?" before their appointment. Full patient statements were transcribed as free text. Two methods assessed whether statements indicated difficulty in each of 13 functional categories: (1) assessment by 2 masked clinicians reading the statement, and (2) a computerized search of the text for specific words or word fragments. Logistic regression models were used to predict the influence of age, gender, and visual acuity on the likelihood of reporting a complaint in each functional category. MAIN OUTCOME MEASURES: Prevalence and risk factors for patient concerns within various functional categories. RESULTS: Reading was the most common functional complaint (66.4% of patients). Other functional difficulties expressed by at least 10% of patients included driving (27.8%), using visual assistive equipment (17.5%), mobility (16.3%), performing in-home activities (15.1%), lighting and glare (11.7%), and facial recognition and social interactions (10.3%). Good agreement was noted between the masked clinician graders and the computerized algorithm for categorization of functional complaints (median κ of 0.84 across the 13 categories). Multivariate logistic regression models demonstrated that the likelihood of reading difficulties increased mildly with age (odds ratio, 1.4 per 10-year increment in age; 95% confidence interval, 1.3-1.6), but did not differ with visual acuity (P = 0.09). Additionally, men were more likely to report driving difficulties and difficulties related to lighting, whereas women were more likely to report difficulty with either in-home activities or facial recognition or social interaction (P<0.05 for all). Mobility concerns, defined as walking difficulty and out-of-home activities, showed no relationship to gender, age, or visual acuity. CONCLUSIONS: Reading was the most commonly reported difficulty, regardless of the patient's diagnosis. Neither visual acuity nor gender were predictive of reading concerns, although, age showed a small effect. Addressing reading rehabilitation should be a cornerstone of low-vision therapy.

Low vision depression prevention trial in age-related macular degeneration: a randomized clinical trial.

PURPOSE: To compare the efficacy of behavior activation (BA) + low vision rehabilitation (LVR) with supportive therapy (ST) + LVR to prevent depressive disorders in patients with age-related macular degeneration (AMD). DESIGN: Single-masked, attention-controlled, randomized, clinical trial with outcome assessment at 4 months. PARTICIPANTS: Patients with AMD and subsyndromal depressive symptoms attending retina practices (n = 188). INTERVENTIONS: Before randomization, all subjects had 2 outpatient LVR visits, and were then randomized to in-home BA+LVR or ST+LVR. Behavior activation is a structured behavioral treatment that aims to increase adaptive behaviors and achieve valued goals. Supportive therapy is a nondirective, psychological treatment that provides emotional support and controls for attention. MAIN OUTCOME MEASURES: The Diagnostic and Statistical Manual IV defined depressive disorder based on the Patient Health Questionnaire-9 (primary outcome), Activities Inventory, National Eye Institute Vision Function Questionnaire-25 plus Supplement (NEI-VFQ), and NEI-VFQ quality of life (secondary outcomes). RESULTS: At 4 months, 11 BA+LVR subjects (12.6%) and 18 ST+LVR subjects (23.4%) developed a depressive disorder (relative risk [RR], 0.54; 95% CI, 0.27-1.06; P = 0.067). In planned adjusted analyses the RR was 0.51 (95% CI, 0.27-0.98; P = 0.04). A mediational analysis suggested that BA+LVR prevented depression to the extent that it enabled subjects to remain socially engaged. In addition, BA+LVR was associated with greater improvements in functional vision than ST+LVR, although there was no significant between-group difference. There was no significant change or between-group difference in quality of life. CONCLUSIONS: An integrated mental health and low vision intervention halved the incidence of depressive disorders relative to standard outpatient LVR in patients with AMD. As the population ages, the number of persons with AMD and the adverse effects of comorbid depression will increase. Promoting interactions between ophthalmology, optometry, rehabilitation, psychiatry, and behavioral psychology may prevent depression in this population.

Fear of falling in age-related macular degeneration.

BACKGROUND: Prior studies have shown age-related macular degeneration (AMD) to be associated with falls. The purpose of this study is to determine if (AMD) and AMD-related vision loss are associated with fear of falling, an important and distinct outcome. METHODS: Sixty-five persons with AMD with evidence of vision loss in one or both eyes and 60 glaucoma suspects with normal vision completed the University of Illinois at Chicago Fear of Falling questionnaire. Responses were Rasch analyzed. Scores were expressed in logit units, with lower scores demonstrating lesser ability and greater fear of falling. RESULTS: Compared to glaucoma suspect controls, AMD subjects had worse visual acuity (VA) (median better-eye VA = 20/48 vs. 20/24, p < 0.001) and worse contrast sensitivity (CS) (binocular CS = 1.9 vs. 1.5 log units, p < 0.001). AMD subjects were also older, more likely to be Caucasian, and less likely to be employed (p < 0.05 for all), but were similar with regards to other demographic and health measures. In multivariable models controlling for age, gender, body habitus, strength, and comorbid illnesses, AMD subjects reported greater fear of falling as compared to controls (ß = -0.77 logits, 95% CI = -1.5 to -0.002, p = 0.045). In separate multivariable models, fear of falling increased with worse VA (ß = -0.15 logits/1 line decrement, 95% CI = -0.28 to -0.03, p = 0.02) and CS (ß = -0.20 logits/0.1 log unit decrement, 95% CI = -0.31 to -0.09, p = 0.001). Greater fear of falling was also associated with higher BMI, weaker grip, and more comorbid illnesses (p < 0.05 for all). CONCLUSIONS: AMD and AMD-related vision loss are associated with greater fear of falling in the elderly. Development, validation, and implementation of methods to address falls and fear of falling for individuals with vision loss from AMD are important goals for future work.

Improving function in age-related macular degeneration: a randomized clinical trial.

PURPOSE: To compare the efficacy of problem-solving therapy (PST) with supportive therapy (ST) to improve targeted vision function (TVF) in age-related macular degeneration (AMD). DESIGN: Single-masked, attention-controlled, randomized clinical trial with outcome assessments at 3 months (main trial endpoint) and 6 months (maintenance effects). PARTICIPANTS: Patients with AMD (n = 241) attending retina practices. INTERVENTIONS: Whereas PST uses a structured problem-solving approach to reduce vision-related task difficulty, ST is a standardized attention-control treatment. MAIN OUTCOME MEASURES: We assessed TVF, the 25-item National Eye Institute Vision Function Questionnaire plus Supplement (NEI VFQ), the Activities Inventory (AI), and vision-related quality of life (QoL). RESULTS: There were no between-group differences in TVF scores at 3 (P = 0.47) or 6 (P = 0.62) months. For PST subjects, mean ± standard deviation TVF scores improved from 2.71±0.52 at baseline to 2.18±0.88 at 3 months (P = 0.001) and were 2.18±0.95 at 6 months (change from 3 to 6 months, P = 0.74). For ST subjects, TVF scores improved from 2.73±0.52 at baseline to 2.14±0.96 at 3 months (P = 0.001) and were 2.15±0.96 at 6 months (change from 3 to 6 months, P = 0.85). Similar proportions of PST and ST subjects had less difficulty performing a TVF goal at 3 months (77.4% vs 78.6%, respectively; P = 0.83) and 6 months (76.2% vs 79.1%, respectively; P = 0.61). There were no changes in the NEI VFQ or AI. Vision-related QoL improved for PST relative to ST subjects at 3 months (F(4, 192) = 2.46; P = 0.05) and at 6 months (F(4, 178) = 2.55; P = 0.05). The PST subjects also developed more adaptive coping strategies than ST subjects. CONCLUSIONS: We found that PST was not superior to ST at improving vision function in patients with AMD, but that PST improved their vision-related QoL. Despite the benefits of anti-vascular endothelial growth factor treatments, AMD remains associated with disability, depression, and diminished QoL. This clinical reality necessitates new rehabilitative interventions to improve the vision function and QoL of older persons with AMD. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.

Driving patterns in older adults with glaucoma.

BACKGROUND: The ability to drive is important for ensuring quality of life for many older adults. Glaucoma is prevalent in this age group and may affect driving. The purpose of this study is to determine if glaucoma and glaucomatous visual field (VF) loss are associated with driving cessation, limitations, and deference to another driver in older adults. METHODS: Cross-sectional study. Eighty-one glaucoma subjects and 58 glaucoma suspect controls between age 60 and 80 reported if they had ceased driving, limited their driving in various ways, or preferred another to drive. RESULTS: Twenty-three percent of glaucoma subjects and 6.9% of suspects had ceased driving (p = 0.01). Glaucoma subjects also had more driving limitations than suspects (2.0 vs. 1.1, p = 0.007). In multivariable models, driving cessation was more likely for glaucoma subjects as compared to suspects (OR = 4.0; 95% CI = 1.1-14.7; p = 0.03). The odds of driving cessation doubled with each 5 decibel (dB) decrement in the better-eye VF mean deviation (MD) (OR = 2.0; 95% CI = 1.4-2.9; p < 0.001). Glaucoma subjects were also more likely than suspects to report a greater number of driving limitations (OR = 4.7; 95% CI = 1.3-16.8; p = 0.02). The likelihood of reporting more limitations increased with the VF loss severity (OR = 1.6 per 5 dB decrement in the better-eye VF MD; 95% CI = 1.1-2.4; p = 0.02). Neither glaucoma nor VF MD was associated with other driver preference (p > 0.1 for both). CONCLUSIONS: Glaucoma and glaucomatous VF loss are associated with greater likelihood of driving cessation and greater limitation of driving in the elderly. Further prospective study is merited to assess when and why people with glaucoma change their driving habits, and to determine if their observed self-regulation of driving is adequate to ensure safety.

Interpretation of low-vision rehabilitation outcome measures.

PURPOSE: This article presents a theoretical interpretation of patient-reported outcomes of low-vision rehabilitation (LVR) using rating scale questionnaires and uses previously published results of LVR outcome studies to illustrate theoretical points and validate assumptions. THEORY: Patients' judgments of the difficulty they have performing tasks are interpreted as magnitude estimates of their functional reserve for each task, which is the difference between their visual ability and the visual ability demanded by the task. We assume that improvements in functional reserve can occur by increasing the patient's visual ability with medical, surgical, or refractive interventions or decreasing the visual ability demanded by the item with activity-specific vision assistive equipment, adaptations, and environmental modifications. Activity-specific interventions cause differential item functioning (intervention-related DIF). Intervention-related DIF makes the measured size of the treatment effect dependent on the item content and the mix of responsive and unresponsive items to intervention. CONCLUSIONS: Because intervention-related DIF depends on the choice of items, the outcome measure selected should be appropriate to the aims of the intervention and the impairment level of the sample to demonstrate the full effects of an intervention. Items that are given extreme positive ratings at preintervention baseline (e.g., "not difficult") have no room for improvement. These items must also be filtered out because they will dilute the measured effect of the activity-specific interventions of LVR.

Comparison of clinician-predicted to measured low vision outcomes.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Responsiveness of the EQ-5D to the effects of low vision rehabilitation.

PURPOSE: This study is an evaluation of the responsiveness of preference-based outcome measures to the effects of low vision rehabilitation (LVR). It assesses LVR-related changes in EQ-5D utilities in patients who exhibit changes in Activity Inventory (AI) measures of visual ability. METHODS: Telephone interviews were conducted on 77 low-vision patients out of a total of 764 patients in the parent study of "usual care" in LVR. Activity Inventory results were filtered for each patient to include only goals and tasks that would be targeted by LVR. RESULTS: The EQ-5D utilities have weak correlations with all AI measures but correlate best with AI goal scores at baseline (r = 0.48). Baseline goal scores are approximately normally distributed for the AI, but EQ-5D utilities at baseline are skewed toward the ceiling (median, 0.77). Effect size for EQ-5D utility change scores from pre- to post-LVR was not significantly different from zero. The AI visual function ability change scores corresponded to a moderate effect size for all functional domains and a large effect size for visual ability measures estimated from AI goal ratings. CONCLUSIONS: This study found that the EQ-5D is unresponsive as an outcome measure for LVR and has poor sensitivity for discriminating low vision patients with different levels of ability.

Development and Validation of the Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire.

PURPOSE: To develop and validate a novel patient-reported outcome (PRO) measure to assess vision-related functioning in individuals with severe peripheral field loss (PFL). DESIGN: Prospective outcome measure development/validation study. METHODS: A 127-item questionnaire was developed based on a prior qualitative interview study. A total of 116 participants with severe PFL due to retinitis pigmentosa (RP) or glaucoma were recruited at the Kellogg Eye Center and completed the Likert-scaled telephone-administered questionnaire. Included participants had a horizontal extent of their visual field <20 degrees (RP) or a mixed or generalized stage 4 to 5 defect using the Enhanced Glaucoma Staging System (glaucoma) in the better seeing eye (or in 1 eye if the fellow eye visual acuity was <20/200). Response data were analyzed using exploratory factor analysis and Rasch modeling. Poorly functioning items were eliminated, confirmatory factor analysis was used to ensure scale unidimensionality, and the model was refit to produce the final instrument. RESULTS: The final Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) Questionnaire contains 53 items across 6 domains: mobility, object localization, object recognition, reading, social functioning, and technology. There were 74 items removed because of high missingness, poor factor loadings, low internal consistency, high local dependency, low item information, item redundancy, or differential item functioning. Using Rasch item calibrations, person ability scores could be calculated for each of the 6 unidimensional LV-SCOPE domains with good test-retest stability. CONCLUSIONS: The LV-SCOPE Questionnaire provides a valid and reliable measure of vision-related functioning across 6 key domains relevant to individuals with severe PFL. Findings support the clinical utility of this psychometrically valid instrument.

Fear of falling and visual field loss from glaucoma.

OBJECTIVE: To determine if visual field (VF) loss resulting from glaucoma is associated with greater fear of falling. DESIGN: Prospective, observational study. PARTICIPANTS: Fear of falling was compared between 83 glaucoma subjects with bilateral VF loss and 60 control subjects with good visual acuity and without significant VF loss recruited from patients followed up for suspicion of glaucoma. METHODS: Participants completed the University of Illinois at Chicago Fear of Falling Questionnaire. The extent of fear of falling was assessed using Rasch analysis. MAIN OUTCOME MEASURES: Subject ability to perform tasks without fear of falling was expressed in logits, with lower scores implying less ability and greater fear of falling. RESULTS: Glaucoma subjects had greater VF loss than control subjects (median better-eye mean deviation [MD] of -8.0 decibels [dB] vs. +0.2 dB; P<0.001), but did not differ with regard to age, race, gender, employment status, the presence of other adults in the home, body mass index (BMI), grip strength, cognitive ability, mood, or comorbid illness (P ≥ 0.1 for all). In multivariate models, glaucoma subjects reported greater fear of falling as compared with controls (ß = -1.20 logits; 95% confidence interval [CI], -1.87 to -0.53; P = 0.001), and fear of falling increased with greater VF loss severity (ß = -0.52 logits per 5-dB decrement in the better eye VF MD; 95% CI, -0.72 to -0.33; P<0.001). Other variables predicting greater fear of falling included female gender (ß = -0.55 logits; 95% CI, -1.03 to -0.06; P = 0.03), higher BMI (ß = -0.07 logits per 1-unit increase in BMI; 95% CI, -0.13 to -0.01; P = 0.02), living with another adult (ß = -1.16 logits; 95% CI, -0.34 to -1.99 logits; P = 0.006), and greater comorbid illness (ß = -0.53 logits/1 additional illness; 95% CI, -0.74 to -0.32; P<0.001). CONCLUSIONS: Bilateral VF loss resulting from glaucoma is associated with greater fear of falling, with an impact that exceeds numerous other risk factors. Given the physical and psychological repercussions associated with fear of falling, significant quality-of-life improvements may be achievable in patients with VF loss by screening for, and developing interventions to minimize, fear of falling.