Vision-specific health-related quality of life in age-related maculopathy patients presenting for low vision services

Few studies have examined the effectiveness of low vision rehabilitation for age-related maculopathy (ARM) patients and its impact on vision-specific health-related quality of life (HRQoL). However, before a multi-site clinical trial can be conducted, appropriate outcome measures need to be identified for ARM patients who seek out low vision rehabilitation, including a vision-specific HR QoL instrument. The 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) was developed to assess vision-specific HRQoL for low vision patients, including those with ARM. This study examines the performance of the NEI VFQ-25 among ARM patients who seek out low vision services and examines its relationship with visual acuity and self-reported use of low vision aids. One hundred and twenty-seven patients were recruited from a University-affiliated low vision clinic. During two telephone interviews, subjects completed the NEI VFQ-25 and a short cognitive test and provided information on general health and use of low vision aids. Additional information on visual acuity and eye health were collected from the medical record. Our results indicate that ARM patients who seek out low vision services report significant impairment in their vision-specific HRQoL. Their NEI VFQ-25 scores were lower compared to other ARM and low vision rehabilitation samples previously studied. The VFQ subscales with the largest deficits were near and distance visual acuities and psychosocial issues (near vision, distance vision, role difficulties, dependency, social functioning, mental health). These subscale scores were lower for those with greater visual acuity impairment. The VFQ subscale scores most impacted by the disease had wide variability and were higher for those who used low vision aids, suggesting that the NEI VFQ-25 is suitable for measuring further decline and treatment-related improvements. Thus, it should be strongly considered for a multi-site clinical trial on the effectiveness of low vision rehabilitation.     

Visual field defects and vision-specific health-related quality of life in African Americans and whites with glaucoma

PURPOSE: To examine the relationship of visual field impairment to vision-specific health-related quality of life and symptoms in a large cohort (N=345) of African Americans and Whites of non-Hispanic origin diagnosed with glaucoma. MATERIALS AND METHODS: Participants consisted of persons > or =55 years of age recruited from university-affiliated ophthalmology and optometry practices in Birmingham, AL who had been diagnosed with glaucoma. Medical records were abstracted to collect information on demographics, visual acuity, and visual fields. A telephone survey was conducted to obtain information on vision-specific health-related quality of life [National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25)], glaucoma symptoms [Glaucoma Symptom Scale (GSS)], and cognitive status (Short Portable Mental Status Questionnaire). Visual fields were used to compute a visual field defect score for each eye based on the Advanced Glaucoma Intervention Study (AGIS) scoring system. RESULTS: Mean NEI VFQ-25 subscale scores ranged from the 50s to 80s. Scores for African Americans and Whites did not differ except for the general health and ocular pain subscales for which African Americans had slightly higher scores. For both African Americans and Whites, as the AGIS score became worse in the better and/or worse eye, there was a decrease in VFQ subscale score for most VFQ subscales including general vision, distance vision, near vision, social functioning, color vision, and peripheral vision (P<0.05). AGIS scores were unrelated to the GSS subscales in African Americans; for Whites, the visual but not the nonvisual subscale was related to AGIS score. CONCLUSIONS: Scores on most subscales of the NEI VFQ-25 and the 2 subscales of the GSS are highly similar in African Americans and Whites of non-Hispanic origin who have been diagnosed with glaucoma. In addition, for both African Americans and Whites, the VFQ subscales for the most part demonstrated good construct validity with respect to the extent of visual field impairment. Results imply that the NEI VFQ-25 and the GSS are appropriate instruments for studying the personal burden of glaucoma in studies whose samples involve both African American and White adults.     

Self-reported visual dysfunction in multiple sclerosis: new data from the VFQ-25 and development of an MS-specific vision questionnaire

PURPOSE: To examine vision-specific health-related quality of life in a cohort of patients with multiple sclerosis (MS) using the 25-Item National Eye Institute Visual Function Questionnaire (VFQ-25), and to identify content areas for a brief MS-specific vision questionnaire. DESIGN: Cross-sectional survey. METHODS: The VFQ-25 and a modified version of the Optic Neuritis Treatment Trial (ONTT) Patient Questionnaire were administered by in-person interview to 80 patients at the University of Pennsylvania MS Center. Binocular visual acuities were obtained following a standard protocol using retroilluminated Early Treatment Diabetic Retinopathy Study charts. RESULTS: Despite a median binocular visual acuity of 20/16 (20/12.5-20/250), VFQ-25 subscale scores in the MS cohort were significantly lower (worse) compared with those of a published reference group of eye disease-free patients (P =.0001-0.009, two-tailed t tests). Rank-correlations of VFQ-25 composite (overall) scores with visual acuity were modest, but significant (r(s) = 0.33, P =.003), supporting construct validity for VFQ-25 scores in MS populations. Seven additional aspects of self-reported visual dysfunction in MS were also identified. CONCLUSIONS: Patients with MS have a high degree of self-reported visual dysfunction that is not entirely captured by visual acuity. The VFQ-25 is an effective measure of self-reported visual loss in MS. A brief MS-specific vision questionnaire may provide additional useful information when administered concurrently with the VFQ-25 in future investigations of MS and other neuroophthalmologic disorders.     

Likert and Guttman scaling of visual function rating scale questionnaires

PURPOSE: To test the assumptions underlying Likert scoring of visual function questionnaires. METHODS: Questionnaires were administered to 284 low-vision subjects by telephone. Each subject was administered two of four questionnaires: ADVS, NEI VFQ-25 plus supplement, expanded VAQ, and VF-14. RESULTS: Z-scores for cumulative frequency of using each rating category across subjects are not linear with rating category rank and items are not the same difficulty for any of the questionnaires. Guttmann coefficients of reproducibility ranged from 57% for the ADVS to 51% for the NEI VFQ-25. Cronbach alphas ranged from 0.92 for the VF-14 to 0.96 for the NEI VFQ; however, inter-item consistency coefficients ranged from 0.24 for the VAQ to 0.45 for the NEI VFQ. Likert scores were significantly correlated between instruments, ranging from 0.66 for NEI VFQ vs ADVS to 0.90 for the VF-14 vs. ADVS. CONCLUSIONS: The rating scales of all four questionnaires fail to satisfy Likert's assumptions. Also, ratings are probabilistic, rather than deterministic, which means that the Likert model is not valid for these questionnaires. However, Likert scores for all four instruments are intercorrelated, suggesting that they are monotonic with the latent subject trait distributed in the low vision sample.     

Likert and Guttman scaling of visual function rating scale questionnaires

purpose To test the assumptions underlying Likert scoring of visual function questionnaires. methods Questionnaires were administered to 284 low-vision subjects by telephone. Each subject was administered two of four questionnaires: ADVS, NEI VFQ-25 plus supplement, expanded VAQ, and VF-14. results Z-scores for cumulative frequency of using each rating category across subjects are not linear with rating category rank and items are not the same difficulty for any of the questionnaires. Guttmann coefficients of reproducibility ranged from 57% for the ADVS to 51% for the NEI VFQ-25. Cronbach alphas ranged from 0.92 for the VF-14 to 0.96 for the NEI VFQ; however, inter-item consistency coefficients ranged from 0.24 for the VAQ to 0.45 for the NEI VFQ. Likert scores were significantly correlated between instruments, ranging from 0.66 for NEI VFQ vs ADVS to 0.90 for the VF-14 vs. ADVS. conclusions The rating scales of all four questionnaires fail to satisfy Likert's assumptions. Also, ratings are probabilistic, rather than deterministic, which means that the Likert model is not valid for these questionnaires. However, Likert scores for all four instruments are intercorrelated, suggesting that they are monotonic with the latent subject trait distributed in the low vision sample.     

Visual function and quality of life in patients with age-related maculopathy: results of the Münster Age and Retina Study (MARS)

BACKGROUND: The aim of this study was to examine the association between increasing severity of age-related maculopathy (ARM) stages, visual function and quality of life. METHODS: Using the 25-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ) in the Münster age and retina study (MARS), 974 patients (normal fundus: n = 208; early ARM: n = 466; late ARM: n = 300) with bilateral gradable fundus photographs were asked about their visual function and quality of life. The NEI VFQ scales with regard to general health, general vision, near vision, distance vision and peripheral vision were assessed. According to the ARM stages, age- and gender-adjusted mean scores were calculated and tested for statistically significant differences. RESULTS: The perception of general health, general vision, near vision, distance vision and peripheral vision was getting worse with increasing severity of ARM stages. Comparing the maculopathy groups, significant differences in age- and gender-adjusted mean scores were found between patients with late ARM and healthy subjects and patients with late and early ARM. Furthermore, we observed for the dimension general vision a significant difference of the mean score between early ARM and healthy control group [mean score; early ARM: 68.7 (0.7) vs. control group: 72.2 (1.1); p = 0.005]. CONCLUSIONS: The results of the NEI VFQ reflect the clinical expectation of an inverse relation between increasing severity of ARM stages and visual function and quality of life.     

神经眼科患者的视觉相关生存质量分析

背景 神经眼科疾病是眼科常见病,并且严重影响患者的生活质量.美国国立眼科研究所视觉功能问卷-39（NEI VFQ-39）可以用来评估视功能对生活质量的影响,但目前中国还缺少将其用于神经眼科疾病的研究. 目的 采用NEI VFQ-39评估神经眼科患者的视觉相关生存质量,为神经眼科患者的治疗及护理提供参考. 方法 选取2012年6月1日至9月30日于解放军总医院神经眼科就诊的97例患者,收集其所有的临床资料及中文版NEI VFQ-39调查量表.以发病眼数量、病种及最佳矫正视力（BCVA）等不同分组方式对NEI VFQ-39各项分数进行比较,同时对NEI VFQ-39分数与较好眼及较差眼的BCVA进行相关分析. 结果 受试患者平均年龄为（36.6±177;14.4）岁,且男女比例无明显差异.VFQ-39总分为57.36（46.50,73.38）,其中精神健康项得分最低,为45.00（35.00,60.00）.4个组疾病中,前部缺血性视神经病变（AION）组除眼痛、依赖程度及周边视力外,其他各项评分均较其余3个组评分低,但差异均无统计学意义（P＞0.05）.双眼发病患者各项得分均较单眼发病者低,除眼痛外,其余各项差异均有统计学意义（P＜0.05）.较好眼BCVA＞20/32的患者得分优于其他两组,与较好眼BCVA＜20/200组比较患者除整体健康及眼痛外,与20/200≤较好眼BCVA≤20/32组比较患者除眼痛、社会活动及色觉外,其余各项比较差异均有统计学意义（P＜0.05）.VFQ-39多数项目得分与较好眼或较差眼的BCVA呈正相关（P＜0.05）,且与较好眼BCVA的相关性较强.结论 神经眼科疾病严重影响患者的视功能及其生活质量,努力提高视功能有助于改善患者的生活质量.     

Influence of cataract and intraocular lens surgery on health-related quality of life

PURPOSE: To evaluate the vision-related quality of life(QOL) in patients undergoing cataract surgery with the Japanese version of the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). SUBJECTS AND METHODS: Subjects were 110 patients [70.4 +/- 9.2 (mean +/- standard deviation) years old] undergoing bilateral cataract surgery. Best-corrected visual acuity was 20/30 or worse in both eyes. The VFQ-25 was recorded before and 2 months after phacoemulsification and foldable intraocular lens implantation, and the influence of various clinical parameters was assessed. The VFQ-25 was also recorded in 69 glaucoma patients with visual field defects in both eyes, and in 31 normal subjects. RESULTS: The VFQ-25 scores before cataract surgery were as low as the scores obtained in glaucoma patients. Cataract surgery significantly improved VFQ-25 scores to the level of normal subjects Statistically significant improvements were observed in subscales such as general vision, near activities, distance activities, driving, peripheral vision, color vision, social functioning, dependency, role difficulties, mental health, and total score (p<0.001, paired t-test). The degree of improvement in VFQ-25 scores did not correlate with preoperative or postoperative visual acuity, uncorrected or corrected. The VFQ-25 scores improved more in younger patients, and improvement in the general vision subscale showed a significant negative correlation with age (r= -0.286, p=0.009, Pearson correlation coefficient). The degree of posterior subcapsular cataract in better eyes showed significant correlation with the improvement in subscales, such as distance activity (r =0.413, p<0.001), driving (r= 0.449, p=0.015), social functioning (r=0.308, p= 0.004), mental health (r=0.330, p=0.002), dependency (r=0.323, p=0.003), and total score (r=0.328, p=0.002). Other types of cataract had no correlation. Men tended to show more improvement in VFQ-25 scores by surgery than women, except for the dependency subscale. CONCLUSION: The current study quantitatively demonstrated that vision-related QOL is significantly impaired in patients with cataract, and that cataract surgery dramatically improves patients' QOL.     

Assessment of the visual function of partially sighted and blind Canadian youth using the VFQ-25 questionnaire: a preliminary study

ObjectiveYoung people are a relatively underrepresented group in literature on poor vision and blindness. This study assessed the quality of life and function of young people who have poor vision or blindness by asking directly about their personal experiences.MethodsA modified version of the VFQ-25 was administered to 47 students at a school for blind youth. All students who received the test had visual acuity scores of 20/100 or worse. The VFQ-25 scoring system was used, and results from additional qualitative questions were themed and ranked. Further analysis was performed, using Spearman's rank correlation coefficient to check for correlation between duration of blindness and VFQ score.ResultsParticipants recorded a composite VFQ score of 65, showing that poor vision had a self-perceived moderate effect on their daily function. Proportion of participant's life spent with visual impairment correlated with higher composite scores. In general, lower scores were reported by participants with worse visual acuity. However, variations were observed in the mental health category.ConclusionsYoung people have a more optimistic and nuanced view of their function than expected based on VFQ scores of other groups. Larger studies, particularly ones including youth in non-specialized schools would be useful to expand these findings.     

Measuring low-vision rehabilitation outcomes with the NEI VFQ-25

PURPOSE: To evaluate the sensitivity of the National Eye Institute Visual Functioning Questionnaire-25 (NEI VFQ-25) to change in visual abilities after low-vision rehabilitation in two different Veterans Administration (VA) low-vision programs METHODS: Seventy-seven legally blind veterans from the Blind Rehabilitation Center (BRC) at Hines VA Hospital and 51 partially sighted veterans from the Visual Impairment Center to Optimize Remaining Sight (VICTORS) program at the Chicago Health Care Network, West Side Division, were administered the NEI VFQ-25 plus supplement in interview format at admission and discharge. Instructions for administration were modified to have study participants answer all the questions as if they were wearing glasses or contact lenses or were using low-vision devices. Interval measures of person ability and item difficulty were estimated from the patients' responses to 34 of the 39 items on the VFQ-25 plus supplement before and after rehabilitation, by the polytomous rating scale measurement model of Wright and Masters. RESULTS: In VICTORS patients, item order by difficulty before rehabilitation agreed with item order for BRC patients. Visual ability scales are used similarly by different patients with different degrees of low vision. Based on prerehabilitation person measure distributions, VICTORS patients were less disabled, as would be predicted by visual acuity, than were BRC patients. After rehabilitation, estimated item difficulty for 4 of the 34 items decreased significantly in both BRC and VICTORS patients. CONCLUSIONS: The present study demonstrates that the NEI VFQ-25 plus supplement can be used to measure the effects of low-vision rehabilitation; however, only 7 of the 34 items tested are sensitive to change after rehabilitation. Targeted activities, such as reading ordinary print, small print, and street signs are easier to perform for graduates of both programs after rehabilitation. The patients' visual ability also shows improvement in both BRC and VICTORS. Improvement in visual ability is independent of change in difficulty of targeted items. Although this was not a controlled clinical trial, the decrease in difficulty of targeted items may reflect the use of low-vision aids and training to make tasks easier. The change in visual ability may reflect positive outcomes of rehabilitation or may be the consequence of patients' overestimates of their functional ability at the time of discharge.     

Vision-related quality of life in corneal graft recipients

AimsTo assess the vision-related quality of life of corneal transplant recipients using the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25), and to identify the socio-demographic factors that associate with patients' self-assessment of perceived visual function.MethodsThirty patients who received corneal transplants were included in this prospective observational, cross-sectional study. Socio-demographic and clinical data, including age, sex, systemic health status, employment status, visual acuity, reason of corneal transplantation, laterality of corneal graft, and follow-up period were collected. NEI VFQ-25 was scored using Rasch analysis. Subgroup analyses were also performed.ResultsAge, sex, visual acuity, and health status had no significant correlation or association with the Rasch-transformed score. Patients who received bilateral corneal grafts were significantly less able socioemotionally than those with unilateral graft. Patients who became unemployed or retired after transplantation were also significantly less able in both visual functioning and socioemotional status.ConclusionCorneal transplant recipients had a decreased vision-related quality of life as demonstrated by the NEI VFQ-25. Apart from anatomical success and visual acuity, ophthalmologists should also consider other aspects of visual outcome. In particular, those who received bilateral grafts require more attention. Employment programmes should be part of corneal transplantation rehabilitation planning.     

Mapping the 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) to EQ-5D Utility Scores

Abstract

Purpose: To develop a mapping algorithm for the estimation of EQ-5D-based utility scores from observed 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) scores, a disease-specific, patient-reported outcome measure used in several retinal disorders to evaluate vision-specific functioning.

Methods: The dataset comprised 951 paired EQ-5D/NEI VFQ-25 observations from 344 patients in RESTORE, a 12-month, randomized, double-blind trial in individuals with visual impairment due to diabetic macular edema. EQ-5D index scores (utilities) were calculated based on the UK tariff. We evaluated 11 models using predictor sets based on the NEI VFQ-25 subscales to estimate utility as a function of NEI VFQ-25 score, based on four modeling techniques. Model performance was assessed by 10-fold cross-validation comparing root mean squared error (RMSE), mean absolute error (MAE) and correlation with EQ-5D score (Pearson and Spearman correlation coefficients).

Results: Mapping results were similar across all techniques and predictor sets. The reverse two-part generalized estimating equation model used fewest predictors and had the best predictive performance (RMSE 0.200, MAE 0.140). Predicted and original EQ-5D values were not strongly correlated (squared Spearman correlation coefficient, 0.34).

Conclusions: Although mapping disease-specific instruments to EQ-5D utilities is a preferred method by some reimbursement bodies, finding an appropriate mapping equation is not straightforward. In this study, mapping NEI VFQ-25 scores to EQ-5D utilities provided low predictive power, independent of the modeling methodology applied, suggesting an inability of the EQ-5D to discriminate vision-related activities, and highlighting that mapping exercises may lead to inaccurate utility values that do not represent patients’ preferences.     

Visual quality of life after macular hole surgery: outcome and predictive factors

BACKGROUND: In the present study we evaluated the functional success after macular hole surgery in correlation to visual quality of life and looked for predictive factors determining surgical success. METHODS: Fifty-nine patients that underwent pars plana vitrectomy for idiopathic macular hole were included. Follow-up visits were performed in regular intervals after surgery and included a clinical examination, optical coherence tomography (OCT) and measurement of visual acuity. To assess the visual quality of life patients filled out the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25) before and three months and one year after surgery. RESULTS: Macular hole closure was achieved in 57 of 59 patients (97%). Mean visual acuity increased from 20/100 preoperatively to 20/34 one year after surgery (p = 0.02). Despite good visual acuity (20/27) in the fellow eye, visual quality of life (VFQ composite score) rose from 75.9 +/- 14.4 (SD) to 81.5 +/- 14.2 one year after surgery (p<0.001). Although there was no correlation between the increase in visual quality of life and visual acuity, the increase in VFQ-25 could be well predicted: low visual acuity and significant impairment on VFQ-25 testing preoperatively made patients most likely to benefit from macular hole surgery. A relatively high retinal thickness measurement at the hole border measured on OCT further increases the predictive value. CONCLUSION: Macular hole surgery is associated with an increase in visual quality of life despite good visual acuity of the fellow eye. Preoperative visual acuity, VFQ-25 value and partly OCT may help to predict the increase in patients' vision related quality of life after surgery.     

The newly established primary care based Welsh Low Vision Service is effective and has improved access to low vision services in Wales

Aim: The aim of this study was to determine whether the new, primary care based, Welsh Low Vision Service (WLVS) improved access to low vision services in Wales and was effective. Method: The impact of the WLVS was determined by measuring the number of low vision appointments; travel time to the nearest service provider; and waiting times for low vision services for 1 year before, and for 1 year after, its establishment. Change in self‐report visual function (using the 7 item NEI‐VFQ), near visual acuity, patient satisfaction and use of low vision aids were used to determine the effectiveness of the service. Results: Following instigation of the WLVS, the number of low vision assessments increased by 51.7%, the waiting time decreased from more than 6 months to less than 2 months for the majority of people, and journey time to the nearest service provider reduced for 80% of people. Visual disability scores improved significantly (p < 0.001) by 0.79 logits and 97.42% patients found the service helpful. Conclusions: The extension of low vision rehabilitation services into primary care identified a considerable unmet burden of need as evidenced by the substantial increase in the number of low vision assessments provided in Wales. The new service is effective and exhibits improved access.     

Psychometric performance of the NEI VFQ-25 in visually normal Latinos: the Los Angeles Latino Eye Study

PURPOSE: To characterize the psychometric performance of the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25) in visually normal Latinos (Mexican Americans). METHODS: The Los Angeles Latino Eye Study (LALES) is a population-based study to assess the prevalence of eye disease and self-reported visual functioning in Latinos aged 40 or more years. Self-reported visual functioning was assessed by using English and Spanish versions of the NEI VFQ-25. Psychometric properties of the NEI VFQ-25, including internal consistency of the subscales and the individual items, were assessed through the Multi-trait Analysis Program-Revised (MAP-R) analysis. Adjusted mean and median subscale scores were compared between English and Spanish speakers to identify any systematic differences. RESULTS: Of the 1917 participants from two census tracts, 1171 participants with no visual impairment were included in this analysis. The mean age of the participants was 52.3 years, 57% of the participants were female, and 67.5% of the participants were Spanish speaking. Median scores for Spanish-speaking participants were significantly lower than those of the English-speaking participants on four subscales: Ocular Pain, General Vision, Vision-Specific Mental Health, and General Health (P < 0.05). Internal consistency for three of eight measurable subscales for the study group was poor (Cronbach alpha < 0.6). CONCLUSIONS: This study reveals psychometric inconsistencies in the NEI VFQ-25 when administered to visually normal Latinos. The difference in mean subscale scores between Spanish and English speakers must be integrated into the development of population norms of visual function. Further detailed psychometric evaluation is needed to determine the validity of this instrument in Latino populations.     

Visual function and subjective perception of visual ability after macular hole surgery

PURPOSE: To evaluate the functional and anatomical results of macular hole surgery and to explore its effect on patients' Health-Related Quality Of Life (HR-QOL) and to investigate the associations between self-reported HR-QOL and conventional measures of visual function. DESIGN: Case series. METHODS: The National Eye Institute 25-Item Visual Function Questionnaire (VFQ-25) and the 36-Item Short-Form Health Survey (SF-36) were self-administered by 30 patients before and 4 months after macular hole surgery. Preoperative, intraoperative, and postoperative clinical data were collected including visual acuity, contrast sensitivity, and metamorphopsia. Multi-item scales rating different aspects of HR-QOL were compared before and after surgery, and their correlation with traditional methods of outcome evaluation was analyzed. RESULTS: Macular hole closure was achieved in 26 patients (87%). Mean LogMAR visual acuity improved by 6 +/- 10 letters for distance and 7 +/- 12 letters for near. Metamorphopsia was reduced by a mean of 35 +/- 70 squares on Amsler chart, and Pelli-Robson contrast sensitivity decreased by a mean of -0.09 +/- 0.3 log units postoperatively. The VFQ-25 composite score as well as scale scores associated with general vision, near vision, vision-related mental health, and role difficulties were significantly improved (P < .05) after successful closure of macular hole. Conversely out of the eight SF-36 health concepts, limitation in usual role activities because of emotional problems was the only one that significantly improved postoperatively. Both baseline and postoperative best-corrected visual acuity significantly correlated with most of the VFQ subscale scores before and after surgery, respectively. CONCLUSIONS: In this case-series, macular hole surgery appears to have a beneficial effect on patients' subjective perception of visual function. The use of vision-targeted health status questionnaires in conjunction with detailed clinical examination provides a more comprehensive overview of individuals' daily well-being after surgical intervention. Further controlled studies are required to confirm our findings.     

Development of a questionnaire to assess vision problems under low luminance in age-related maculopathy

PURPOSE: To develop a questionnaire for assessing self-reported visual problems under low luminance and at night for use in studies on age-related maculopathy (ARM). METHODS: The questionnaire was developed in three steps: (1) Content for questionnaire items was identified through focus groups of older adults with ARM and those exhibiting normal retinal aging. The topic for discussion was "vision at night and under low lighting." Discussion was audiotaped, transcribed, and subjected to content analysis to identify problem categories expressed by patients. (2) This content was used to develop a preliminary questionnaire administered by telephone to persons with ARM or normal retinal aging. Principal-components analysis identified groups of items that formed the questionnaire's subscales that were evaluated for internal consistency, and an item-reduction strategy was implemented to generate a briefer questionnaire. (3) Psychometric properties of the shortened Low-Luminance Questionnaire (LLQ) were determined, including construct validity, criterion validity, and test-retest reliability. RESULTS: The 32-item LLQ has six subscales (driving, extreme lighting, mobility, emotional distress, general dim lighting, and peripheral vision), all with good internal consistency (Cronbach alpha > or = 0.82). Scores on LLQ subscales correlated moderately with nearly all National Eye Institute Visual Function Questionnaire (NEI VFQ)-25 subscales and decreased in value (indicating more disability) for patients with increasing ARM disease severity. Whereas rod-mediated parameters of dark adaptation were significantly associated with LLQ subscale scores (r = 0.19-0.43, all P < 0.03), cone-mediated parameters were not. Test-retest reliability ranged from 0.74 to 0.88 for all subscales (P < 0.0001), except for peripheral vision (0.46; P = 0.0003), which also exhibited a ceiling effect in almost half of the respondents. CONCLUSIONS: The 32-item LLQ, derived from the content of focus group comments by persons with ARM, has good construct validity, subscale scores related to rod-mediated visual function, and good test-retest reliability for five of six subscales. The LLQ may ultimately be useful in patient-centered evaluation of the outcome of interventions to prevent ARM or to arrest progression of early disease.     

Vision‐related function after low‐dose transpupillary thermotherapy versus photodynamic therapy for neovascular age‐related macular degeneration

Purpose: To compare the effects of low‐dose transpupillary thermotherapy (TTT) and verteporfin photodynamic therapy (PDT) on patient‐reported visual function using the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ‐25) in patients with occult neovascular age‐related macular degeneration (AMD). Methods: Patients were randomized to receive either low‐dose TTT (and sham PDT) (n = 52) or PDT (and sham TTT) (n = 46). Patients were followed for 12 months with retreatment according to clinical assessment. The clinical outcome of this study has been recently reported. The NEI VFQ‐25 questionnaire was administered at baseline and at 12 months. Results: Forty‐two patients (80.1%) in the TTT group and 37 patients (80.0%) in the PDT group completed the questionnaire at the 12‐month follow‐up. The mean change in the NEI VFQ‐25 composite score was +1.2 for the TTT group (p > 0.05) and +0.7 for PDT group (p > 0.05). None of the subscale categories showed significant changes between treatment groups at 12 months. Subgroup analysis showed that NEI VFQ‐25 scores were lower in patients treated in their better‐seeing eye. Conclusion: In this randomized study on patients with occult neovascular AMD, low‐dose TTT and PDT appeared to be equally potent at stabilizing patient‐reported visual function. However, the study was underpowered for this conclusion to be made firmly. Also, given the impressive results obtained with ranibizumab for all types of neovascular AMD, neither PDT nor low‐dose TTT should be considered as first‐line treatments.     

Application of stochastic measurement models to visual function rating scale questionnaires

PURPOSE: To test hypotheses that low vision patient responses to visual function rating scale questionnaires conform to an additive conjoint structure and that the Likert score is a sufficient statistic for the latent patient trait; to compare results for two competing stochastic measurement models; and to determine if different questionnaires measure the same construct in low vision patients. METHODS: Visual function rating scale questionnaires were administered to 284 low vision subjects by telephone. Each subject was administered two of four questionnaires: ADVS, NEI VFQ-25 plus supplement, expanded VAQ, and VF-14. RESULTS: Data were analyzed with the Muraki item response model and the Andrich measurement model. The estimates of latent person, item, and response threshold measures from the two models are linearly related. The Muraki model produced a better overall fit to the item response data, the Andrich model produced a better fit to the average ratings for each person and item. Fit statistics for the Andrich model were proportional to the item-dependent discrimination parameter in the Muraki model. The ADVS was the most accurate measure and the NEI VFQ was the least. Reliability was similar for all four instruments. Person measures for each pair of instruments were linearly related indicating that all four instruments measured the same construct. The person measure estimate from the Andrich model is monotonic with the average rating. That relationship suggests a transformation of the Likert score that can correct the floor and ceiling effects in rating scale data. CONCLUSIONS: Patient responses to all four questionnaires conform to varying degrees to an additive conjoint structure. The Likert score is a sufficient statistic for the ADVS and the VAQ, but not for the NEI VFQ or VF-14. All four instruments measure the same construct in the low vision population, but they differ in measurement accuracy and precision.     

Measuring outcomes of vision rehabilitation with the Veterans Affairs Low Vision Visual Functioning Questionnaire

PURPOSE: To evaluate the sensitivity to change, in patients who undergo vision rehabilitation, of the Veteran Affairs (VA) Low Vision Visual Functioning Questionnaire (LV VFQ-48), which was designed to measure the difficulty visually impaired persons have in performing daily activities and to evaluate vision rehabilitation outcomes. METHODS: Before and after rehabilitation, the VA LV VFQ-48 was administered by telephone interview to subjects from five sites in the VA and private sector. Visual acuity of these subjects ranged from near normal to total blindness. RESULTS: The VA LV VFQ exhibited significant differential item functioning (DIF) for 7 of 48 items (two mobility tasks, four reading tasks, and one distance-vision task). However, the DIF was small relative to baseline changes in item difficulty for all items. Therefore, the data were reanalyzed with the constraint that item difficulties do not change with rehabilitation, which assigns all changes to the person measure. Subjects in the inpatient Blind Rehabilitation Center (BRC) program showed the largest changes in person measures after vision rehabilitation (effect size = 1.9; t-test P < 0.0001). The subjects in the outpatient programs exhibited smaller changes in person measures after rehabilitation (effect size = 0.29; t-test P < 0.01). There was no significant change in person measures for the control group (test-retest before rehabilitation). CONCLUSIONS: In addition to being a valid and reliable measure of visual ability, the VA LV VFQ-48 is a sensitive measure of changes that occur in visual ability as a result of vision rehabilitation. Patients' self-reports of the difficulty they experience performing daily activities measured with this instrument can be used to compute a single number, the person measure that can serve as an outcome measure in clinical studies. The VA LV VFQ-48 can be used to compare programs that offer different levels of intervention and serve patients across the continuum of vision loss.