Quality of life assessment in blindness prevention interventions

Assessment of cataract surgery outcomes in Nampula (Mozambique): visual acuity, visual function and quality of life

BACKGROUND

Despite advances in surgical techniques, cataract remains the leading cause of preventable blindness, and massive surgeries have been adopted as a strategy to change this situation. Monitoring the results of cataract surgeries has become imperative to ensure their quality. Therefore, this study aims to assess the cataract surgery outcomes performed at the Central Hospital of Nampula Mozambique.

METHODS

This is a prospective and longitudinal study in which translation, cultural adaptation and validation of the visual function (VF) and quality of life (QoL) questionnaire were performed. The appearance, content, construct, criterion, internal consistency and responsiveness were validated using the most common methods and indicators. Visual acuity (VA), VF and QoL were evaluated on 447 patients before and after surgery by t-test and effect sizes.

RESULTS

VF and QoL questionnaires showed one-dimension, good values of TLI (0.973, 0.951) and SRMR (0.057, 0.054), and for each item, weights > 0.7, H2 > 0.5, ranges > 5.8 and the RMSEA < 0.08. Correlations for criterion validity were high and for responsiveness were high for QoL and moderate for VF one and the ordinal Cronbach's alpha coefficients were greater than 0.97. Difference between VA, VF and QoL before and after surgery was statistically significant (p < 0.001). After surgery, 74.3% of patients had good, 23.5% had borderline and 2.2% had poor VA.

CONCLUSIONS

The cataract surgery outcomes are outside the WHO recommendations regarding VA, but they have had a great impact on improving VF and QoL. The questionnaires showed excellent psychometric properties and should be used in daily clinical practice to evaluate the results of cataract surgeries.

The path linking disease severity and cognitive function with quality of life in Parkinson's disease: the mediating effect of activities of daily living and depression

BACKGROUND

Research on quality of life (QOL) with Parkinson's disease (PD) has examined direct influencing factors, not mediators. The study aim was to explore whether PD severity and poor cognitive function may decrease physical and mental QOL by reducing activities of daily living (ADL) and increasing depression in sequence.

METHODS

We conducted a cross-sectional questionnaire study of 150 PD hospital patients in China. PD severity, cognitive function, ADL, depression, and QOL were evaluated. We used structural equation modeling to analyze the mediating effects of ADL and depression on the association between PD severity/cognition and the physical health and mental health component summary scores measured by the SF36 quality of life instrument.

RESULTS

There was a significant mediating effect of PD severity on physical health via ADL and depression (95% CI: - 0.669, - 0.026), and a significant direct effect (p < 0.001). The mediating effect of PD severity on mental health via ADL and depression was significant (95% CI: - 2.135, - 0.726), but there was no direct effect (p = 0.548). There was a significant mediating effect of cognitive function on physical health via ADL and depression (95% CI: 0.025, 0.219) and a significant direct effect (p < 0.001). The mediating effect of cognitive function on mental health via ADL and depression was significant (95% CI: 0.256, 0.645), but there was no direct effect (p = 0.313). The physical health models showed a partial mediation, and the mental health models showed a complete mediation, of ADL and depression.

CONCLUSIONS

PD severity and cognitive function increase depression by reducing ADL, leading to lower QOL, and directly or indirectly affect physical health and mental health through different pathways.

Association of Low Luminance Questionnaire With Objective Functional Measures in Early and Intermediate Age-Related Macular Degeneration

Purpose

To determine whether Low Luminance Questionnaire (LLQ) scores are associated with objective measures of visual function in early and intermediate age-related macular degeneration (AMD).

Methods

Cross-sectional study of subjects with early AMD Age-Related Eye Disease Study (AREDS) stage 2, N = 33), intermediate AMD (AREDS stage 3, N = 47), and age-matched healthy controls (N = 21). Subjects were interviewed with the LLQ. Psychophysical tests performed included best-corrected visual acuity (BCVA), mesopic microperimetry, dark adaptometry (DA), low luminance visual acuity (LLVA), and cone contrast test (CCT). Low luminance deficit (LLD) was the difference in the number of letters read under photopic versus low luminance settings. The relationship between LLQ and visual function test scores was assessed with linear regression.

Results

Subjects with intermediate AMD had significantly lower LLQ composite scores (mean = 75.8 ± 16.7; median = 76, range [29, 97]) compared with early AMD (mean = 85.3 ± 13.3; median = 88, range [50, 100], P = 0.007) or controls (mean = 91.4 ± 6.5; median = 94, range [79, 99], P < 0.001) in the overall cohort. LLQ composite scores were associated with computerized BCVA (β = 0.516), computerized LLVA at two background luminance (1.3 cd/m², β = 0.660; 0.5 cd/m², β = 0.489) along with their respective computerized LLDs (β = −0.531 and −0.467), rod intercept (β = −0.312), and CCT green (β = 0.183) (all P < 0.05). Only the computerized LLVAs and computerized LLDs remained statistically significant after adjusting for AMD versus control status (P < 0.05). Among AMD subjects, LLQ composite scores were significantly associated with the computerized LLVAs (β = 0.622 and 0.441) and LLDs (β = −0.795 and −0.477) at both the 1.3 and 0.5 cd/m² luminance levels, respectively, and these associations remained significant after adjusting for AMD severity (P < 0.05).

Conclusions

Among subjects with early and intermediate AMD, LLQ scores were significantly associated with computerized LLVA and LLD. LLQ is a useful patient-centered functional measure of visual impairment in early and intermediate AMD.

Choosing appropriate patient-reported outcomes instrument for glaucoma research: a systematic review of vision instruments

PURPOSE

To identify vision Patient-Reported Outcomes instruments relevant to glaucoma and assess their content validity.

METHODS

MEDLINE, MEDLINE in Process, EMBASE and SCOPUS (to January 2009) were systematically searched. Observational studies or randomised controlled trials, published in English, reporting use of vision instruments in glaucoma studies involving adults were included. In addition, reference lists were scanned to identify additional studies describing development and/or validation to ascertain the final version of the instruments. Instruments' content was then mapped onto a theoretical framework, the World Health Organization International Classification of Functioning, Disability and Health. Two reviewers independently evaluated studies for inclusion and quality assessed instrument content.

RESULTS

Thirty-three instruments were identified. Instruments were categorised into thirteen vision status, two vision disability, one vision satisfaction, five glaucoma status, one glaucoma medication related to health status, five glaucoma medication side effects and six glaucoma medication satisfaction measures according to each instruments' content. The National Eye Institute Visual Function Questionnaire-25, Impact of Vision Impairment and Treatment Satisfaction Survey-Intraocular Pressure had the highest number of positive ratings in the content validity assessment.

CONCLUSION

This study provides a descriptive catalogue of vision-specific PRO instruments, to inform the choice of an appropriate measure of patient-reported outcomes in a glaucoma context.

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.

A pre- and post-treatment evaluation of vision-related quality of life in uveitis

Aim:

To study the effect of treatment on vision-related quality of life (VR-QOL) in uveitis patients.

Materials and Methods:

Interviewer-administered questionnaire-based evaluation of visual function and VR-QOL in Tamil-speaking adult patients with active uveitis at presentation and follow-up by the same interviewer.

Results:

Ninety-eight patients participated in this study. There was a statistically significant improvement in VR-QOL in all the scales following treatment (P < 0.001). Patients with chronic uveitis showed better improvement upon treatment than patients with acute uveitis. The visual symptoms scale showed moderate gains following treatment (effect size 0.56). Persons with bilateral disease had poorer mean scores compared to those with unilateral disease. Visual acuity was closely correlated with VR-QOL scores.

Conclusion:

The VR-QOL measurement has shown that it is sensitive to demonstrate the problems of patients with uveitis irrespective of their demographic profile. The scores improved significantly in patients with uveitis following treatment and have shown close correlation to visual acuity thus demonstrating that VR-QOL is effective in assessing the response to treatment.

Health-related quality of life following blind rehabilitation

PURPOSE

The purpose of this study was to investigate the effect of residential blind rehabilitation on patients' vision-targeted health-related quality of life (HRQOL) and general physical and mental function.

METHOD

The National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ) plus appendix questions, the 12-item Short-Form Health Survey (SF-12), Hope Scale and Coopersmith self-esteem inventory were administered to 206 legally blind veterans prior to their entering a residential (in-patient) blind rehabilitation program and again to 185 and 176 of the original cohort at 2 and 6 months after completion of the rehabilitation program, respectively. Data on visual acuity, visual field extent, contrast sensitivity and scanning ability were also collected. The duration of the in-patient rehabilitation programs ranged from 11 to 109 days. Questionnaire scores were compared pre-rehabilitation and post-rehabilitation.

RESULTS

Following rehabilitation there was a significant improvement in nine of 11 NEI VFQ subscales and in a composite score at both the 2- and 6-month post-rehabilitation intervals. Mental health (SF-12) and self esteem also improved significantly although physical health ratings declined over the course of the study (approximately 10 months).

CONCLUSIONS

Residential blind rehabilitation appears to improve patients' self-reported vision-targeted HRQOL, self-esteem and mental health aspects of generic HRQOL.

Vision rehabilitation: recipients' perceived efficacy of rehabilitation

OBJECTIVE/PURPOSE

This survey was conducted to determine the effect on activities of daily living of persons who report that they have received vision rehabilitation.

DESIGN/METHODOLOGY

This study used a clinical sample to gather information from 417 patients. Of the 417, 105 reported receiving vision rehabilitation. The efficacy of rehabilitation was assessed by asking 20 questions about their activities of daily living prior to and after their rehabilitation. A retrospective pretest (post-then-pre) design was used. Paired t tests were conducted to evaluate the effect of rehabilitation.

RESULTS

A significant difference was found for 13 of 20 questions. Difficulty reading ordinary prints in newspapers showed a large effect size (p=0.0005). Difficulty reading the small print in a telephone book showed a large effect size (p=0.0005). Difficulty doing work or hobbies that require one to see up close showed a moderate effect size (p=0.0005). Difficulty finding something on a crowded shelf showed a moderate effect size (p=0.0005). Difficulty figuring out whether bills received are accurate showed a moderate effect size (p=0.0005). Difficulty shaving, styling one's hair, or putting on makeup showed a small effect size (p=0.016). Difficulties seeing and enjoying programs on television showed a moderate effect size (p=0.0005).

CONCLUSION

Patients with low vision who report having received vision rehabilitation show significant improvements in activities of daily living or specific types of functioning after rehabilitation. Improvement in both near and distance vision activities and in social activities indicates daily functioning was improved and that barriers to activities of daily living were removed.

Cataract visual impairment and quality of life in a Kenyan population

AIMS

To evaluate the World Health Organization Prevention of Blindness and Deafness 20-item Visual Functioning Questionnaire (WHO/PBD VF20), a vision-related quality of life scale, and to describe the relationship between cataract visual impairment and vision- and generic health-related quality of life, in people >or=50 years of age in Nakuru district, Kenya.

METHODS

The WHO/PBD VF20 was pilot tested and modified. 196 patients with visual impairment from cataract and 128 population-based controls without visual impairment from cataract were identified through a district-wide survey. Additional cases were identified through case finding. Vision- and health-related quality of life were assessed using the WHO/PBD VF20 scale and EuroQol generic health index (European Quality of Life Questionnaire (EQ-5D)), respectively. WHO/PBD VF20 was evaluated using standard psychometric tests, including factor analysis to determine item grouping for summary scores.

RESULTS

The modified WHO/PBD VF20 demonstrated good psychometric properties. Two subscales (general functioning and psychosocial) and one overall eyesight-rating item were appropriate for these data. Increased severity of visual impairment in cases was associated with worsening general functioning, psychosocial and overall eyesight scores (p for trend <0.001). Cases were more likely to report problems with EQ-5D descriptive dimensions than controls (p<0.001), and, among cases, increased severity of visual impairment was associated with worsening self-rated health score.

CONCLUSION

The modified WHO/PBD VF20 is a valid and reliable scale to assess vision-related quality of life associated with cataract visual impairment in this Kenyan population. The association between health-related quality of life and visual impairment reflects the wider implications of cataract for health and well-being, beyond visual acuity alone.

The development of the Indian vision function questionnaire: questionnaire content

AIM

To elicit problem statements describing the consequences of vision impairment as a first step towards the development of a vision related quality of life instrument for use in India

METHODS

46 focus groups were conducted in three regions of India. Separate focus groups were held for men and women and according to disease categories: cataract (24), glaucoma (six), diabetic retinopathy or macular degeneration (10), and "mixed low vision" (six). Facilitators followed a topic guide and sessions were audio taped and transcribed. Problem statements were extracted and coded and summarised into major problem domain areas.

RESULTS

Nearly 5000 problem statements, an average of 15 statements per participant, were consolidated into 18 broad domain areas. The most important problem areas accounting for over 50% of all statements were ambulation, household or occupational activities, vision symptoms, and people recognition. A further quarter of statements related to difficulties with eating and drinking, psychological concerns, self care, reading, and watching television. Problem statements were similar across the disease groups, although rankings varied.

CONCLUSIONS

The functional and psychological impacts described by visually impaired participants in India are similar to those reported in other population settings although the context and impact of problems vary.

Design of an individualised measure of the impact of macular disease on quality of life (the MacDQoL)

The aim of this study was to design an individualised questionnaire to measure the impact of macular disease (MD) on quality of life (QoL). Principles underlying the Schedule for the Evaluation of Individual Quality of Life (SEIQoL) interview method and the Audit of Diabetes-Dependent Quality of Life (ADDQoL) diabetes-specific questionnaire influenced the Macular Disease-Dependent Quality of Life (MacDQoL) design. The MacDQoL specifies domains of QoL that were selected using focus group methodology and refined following a postal pilot study of members of the UK Macular Disease Society (MDS). Respondents rated the impact of MD on each domain and the importance of each domain to their QoL. Mean domain scores from 69 respondents indicated that MD had a negative impact on all the domains of QoL investigated in the measure. There was preliminary evidence of good internal consistency reliability (Cronbach's alpha = 0.93, n = 37). Respondents who were registered partially sighted (P/S) or blind reported poorer QoL than those who were not registered (Kruskal-Wallis: chi2 = 14.03, n = 62, p < 0.001). This evidence suggests that the measure will be sensitive to subgroup differences. The instrument has been further refined following the pilot study. The MacDQoL is being used in clinical trials and psychometric evaluation of the measure will be carried out using trial data. The measure is available for clinical use and has been linguistically validated in 15 other languages.

Disparities between ophthalmologists and their patients in estimating quality of life

PURPOSE OF REVIEW

Numerous types of instruments can measure quality of life in a given state of health. This article reviews studies that have measured quality of life of patients and physicians for various types of disease states by using a generic preference-based method known as the time tradeoff method of utility analysis. Of particular interest are comparisons of quality of life estimates between patients and physicians for common ophthalmologic conditions.

RECENT FINDINGS

In nearly all of the studies identified, the quality of life estimates of patients differed significantly from those of physicians. In studies involving macular disease, cataracts, and numerous other types of medical conditions, physicians generally underestimated the impact of the condition on patients' quality of life. Less of a disparity between patients and physicians has been reported for estimates of quality of life with glaucoma. Differences in quality of life estimates may be related to poor physician-patient communication.

SUMMARY

It is important to appreciate the differences in preferences of patients and physicians. Because only patients themselves know their values and needs regarding treatments and outcomes, physicians should routinely elicit patients' preferences and allow them to participate in decision making about treatment. At the societal levels, patients' preferences should help guide decisions including how to allocate finite health care resources. An important tool for this purpose is cost-utility analysis, which incorporates data on patient preferences, along with survival and cost data, to compare the values of competing health care interventions.

Development and Validation of a Multidimensional Quality-of-Life Scale for Myopia

BACKGROUND

Five dimensions of health-related quality of life in myopia were hypothesized to affect satisfaction with visual correction modality. Items on these dimensions reflected the frequency of visual compromise and ocular symptoms; individual tolerance of these compromises and symptoms; cosmesis; psychological constructs (including situation-dependent characteristics such as adaptability, self-efficacy, and subjective well-being); and personality traits such as extraversion and introversion.

METHODS

Psychologically oriented items and visually oriented items were developed in two stages involving 1,647 participants. Item development was based on a comprehensive literature review, interviews with experts, myopic subjects, and graduate students, and written feedback. Items were selected through factor analysis and the examination of their ability to discriminate between treatment conditions (spectacle wear, daily use of contact lenses, continuous use of contact lenses, or laser-assisted in-situ keratomileusis for myopia). After development, selection, and validation of the psychological items and then the vision items, a final multidimensional scale combining both types of items was designed. The scale was administered to 124 subjects whose myopia was corrected by one of several treatment modalities to determine final construct validity.

RESULTS

Using principal axis factoring and oblimin with Kaiser normalization rotation methods, five factors with strong item loadings evolved as hypothesized. The final multidimensional scale consisted of 13 items related to specific aspects of frequency of visual compromise and ocular symptoms with 13 corresponding items for level of tolerance for these problems; three items related to cosmesis; 10 items related to psychological characteristics; and six items related to personality traits. Good internal consistency in each factor (Cronbach's alpha range, 0.76 to 0.92) for the scale was evident.

DISCUSSION

This report describes the development and validation of an easily administered, short, effective multidimensional health-related quality-of-life questionnaire for use in selecting and measuring success of methods for correcting myopia.

Development of a Questionnaire to Assess Subjective Vision Score in Myopes Seeking Refractive Surgery

PURPOSE

To assess vision in patients with myopia and myopic astigmatism before and after refractive surgery.

METHODS

A prospective controlled study of visual quality amongst myopes and astigmatic myopes. Focus groups, ophthalmic surgeons, and questionnaire experts devised a Subjective Vision Questionnaire (SVQ), modified after a pilot trial. Participants were administered the SVQ before clinical evaluation. Items answered by over 95%, with factor loadings > 0.55 were included. Test-retest reliability was assessed by repeat testing. Factor analysis identified groups of questions measuring particular dimensions of data.

RESULTS

Sixty-seven items were answered by 128 patients and reduced to 24 items in a final questionnaire. Factor analysis identified six types of questions within the questionnaire, the most important of which was related to driving.

CONCLUSION

The simplicity, low cost, and psychometric properties of the Subjective Vision Questionnaire support its use clinically and in research.

The measurement of vision disability

The American Medical Association's (AMA) visual efficiency scale, a vision disability metric based on visual impairment measurements, was adopted in 1925. That scale was based on a 30-year history of theoretical models in vision economics, a misinterpretation of Snellen notation for visual acuity, and an erroneous application of Weber's psychophysical law. The AMA visual efficiency scale survived uncontested for 75 years. In 2001, the AMA adopted a new vision disability scale based on logarithmic transformations of visual acuity and visual field diameter. Like the earlier visual efficiency scale, the new scale is theoretical-it is not supported by any data that speak to the relationship between vision disability and visual impairments. Attempts to measure vision disability date to the early 1980s with the development of self-assessment visual function rating scale questionnaires. Nearly all of the questionnaires developed over the last 20 years use Likert scales, but use them incorrectly. The development of a vision disability metric based on Likert scaling parallels the historical development of other forms of measurement. A tutorial review of psychometrics-classical test theory, item response theory, and Rasch analysis-shows how vision disability measurement scales can be estimated from Likert-type visual function rating scales. We conclude that preliminary data relating measures of vision disability to measures of visual acuity and visual fields support the new AMA vision disability scale.

Vision, visual needs, and quality of life of older people in rural environments: a report and synthesis of a meeting

Vision as an aspect of rural aging was a major portion of the First International Conference on Rural Aging. Various perspectives on the relationship of vision to rural aging were presented in two symposia, two paper sessions, one workshop and the poster session (a total of 28 presentations). In summarizing this rich and varied material, the author emphasizes that: (a) vision is important to maintaining a healthy, active life as one ages; (b) impaired vision is generally preventable or treatable; (c) well-designed community programs can assist in prevention and treatment; and (d) assessing the effects of these programs requires evaluation of patients' quality of life. More research is needed to refine strategies for creating, maintaining and evaluating community-based eye care programs and integrating them with existing public health or other community programs.

Prevalence of visual impairment, blindness, and cataract surgery in the Hong Kong elderly

BACKGROUND

The prevalence of vision impairment, unilateral/bilateral blindness, and cataract surgery were estimated in a population based survey among the elderly in a suburban area of Hong Kong.

METHODS

15 public, private, and home ownership scheme housing estates in the Shatin area of Hong Kong were subjected to cluster sampling to randomly select a cross section of people 60 years of age or older. Visual acuity measurements and ocular examinations were conducted at a community site within each estate. The principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18.

RESULTS

A total of 3441 subjects from an enumerated population of 4487 (76.7%) completed an eye examination. The prevalence of presenting visual acuity less than 6/18 in at least one eye was 41.3%; and 73.1% in those 80 years of age or older. Unilateral blindness (acuity <6/60) was found in 7.9% of subjects and bilateral blindness in 1.8%. Refractive error and cataract were, respectively, the main causes of vision impairment and blindness. Visual impairment with either eye <6/18 increased with advancing age and was more prevalent in males, the less educated, and those living in public housing estates. The prevalence of cataract surgery was 9.1% and was associated with advancing age and less education.

CONCLUSIONS

Blindness and visual disability were common in this socioeconomically advanced population, with most of it easily remedied. Because of a rapidly ageing population, healthcare planners in Hong Kong must prepare for an increasing burden of visual disability and blindness.

Inflammatory conditions of the eye associated with rheumatic diseases

Ocular inflammation occurs in many patients with systemic rheumatic disease. The best examples are rheumatoid arthritis, juvenile rheumatoid arthritis, temporal arteritis, systemic lupus erythematosus, Wegener's granulomatosis, polyarteritis nodosa, relapsing polychondritis, and Adamantiades-Behçet's disease. Ocular inflammation may precede the symptoms of the systemic disease and can be helpful in systemic diagnosis. After diagnosis, ocular inflammation can mark the severity of the systemic condition. Thus, prompt diagnosis and treatment of inflammatory conditions of the eye are warranted and may be sight- and life-saving.

Visual function assessment questionnaires

With increased emphasis on functional outcomes in ophthalmology, third-party health care payers and research funding agencies have turned their attention to the development and use of visual function questionnaires. Since 1980, more than a dozen such self-report visual function questionnaires have been developed. All of these instruments include items that ask about specific daily activities; patients must respond with a rating that represents the level of difficulty that they experience with the activity described. This article reviews all of the known instruments, with special attention paid to their validity and reliability. Most validation studies have reported high response consistency across items and significant correlations of instrument scores with visual impairment measures. Only two studies have measured test-retest reliability. The developers of visual function questionnaires typically divide the items into several different subscales, suggesting that different variables are being measured. Although the items are very similar for the different instruments, there is little agreement among instruments on the definition of subscales. All instruments are scored as the average of the ordinal patient ratings across items for each subscale and/or for the total instrument. Measurement issues underlying the scoring of ordinal patient ratings are discussed. It is argued that unless the instruments can be converted to interval scales, the averaging of patient ratings does not yield true measurements. The three visual function questionnaires that were calibrated with a statistical item response model, which estimates interval scales, are reviewed. It is concluded that future research and development should devote additional attention to the measurement properties of functional assessment instruments.

Evaluation of the NEI visual functioning questionnaire as an interval measure of visual ability in low vision

The National Eye Institute developed a visual functioning questionnaire (NEI-VFQ) designed to assess health-related quality of life of patients with visual impairments. The developers of the NEI-VFQ distributed the original 52 items into 13 different domains. The recommended method for scoring the NEI-VFQ is to linearly transform the sum of the ordinal ratings to each item within each domain to produce 13 scores. The major shortcoming of this scoring method is that sums of ordinal numbers do not necessarily generate valid measurement scales. However, Rasch models can be used to estimate interval measurement scales from ordinal responses to items. We administered 27 items from the 52-item NEI-VFQ to 341 patients with low vision. Rasch analysis was used to estimate the 'visual ability' required by each item for a particular response (item measures) and to estimate the 'visual ability' of each patient (person measures). The validity of the model was evaluated by examining the distributions of residuals for item and person measures. We observed that the 17 items we tested from the NEI-VFQ that require difficulty ratings produce a valid interval scale for low-vision patients. The estimated person measures of visual ability are linear with log MAR acuity. The ten items that require frequency or level of agreement ratings do not work together to produce a valid interval scale. Rather, these items appear to be confounded by other variables distributed in the patient sample (e.g. psychological state). The visual ability scale estimated from the 17 NEI-VFQ items is proportional to the visual ability scales estimated from two earlier studies that also elicited difficulty ratings from low-vision patients.

Design of the low vision quality-of-life questionnaire (LVQOL) and measuring the outcome of low-vision rehabilitation

PURPOSE

To design and validate a vision-specific quality-of-life assessment tool to be used in a clinical setting to evaluate low-vision rehabilitation strategy and management.

METHODS

Previous vision-related questionnaires were assessed by low-vision rehabilitation professionals and patients for relevance and coverage. The 74 items selected were pretested to ensure correct interpretation. One hundred and fifty patients with low vision completed the chosen questions on four occasions to allow the selection of the most appropriate items. The vision-specific quality of life of patients with low vision was compared with that of 70 age-matched and gender-matched patients with normal vision and before and after low-vision rehabilitation in 278 patients.

RESULTS

Items that were unreliable, internally inconsistent, redundant, or not relevant were excluded, resulting in the 25-item Low Vision Quality-of-Life Questionnaire (LVQOL). Completion of the LVQOL results in a summed score between 0 (a low quality of life) and 125 (a high quality of life). The LVQOL has a high internal consistency (alpha = 0.88) and good reliability (0.72). The average LVQOL score for a population with low vision (60.9 +/- 25.1) was significantly lower than the average score of those with normal vision (100.3 +/- 20.8). Rehabilitation improved the LVQOL score of those with low vision by an average of 6.8 +/- 15.6 (17%).

CONCLUSIONS

The LVQOL was shown to be an internally consistent, reliable, and fast method for measuring the vision-specific quality of life of the visually impaired in a clinical setting. It is able to quantify the quality of life of those with low vision and is useful in determining the effects of low-vision rehabilitation.

Implementation methods for vision related quality of life questionnaires

AIM

To determine the most reliable and consistent method and time interval over which to implement a vision impairment quality of life assessment tool.

METHODS

117 patients with low vision aged 9-101 years were assigned into three age, sex, and visual function matched groups (n = 39 in each) to answer the Low Vision Quality of Life (LVQOL) questionnaire by post, telephone, or in person. The LVQOL questionnaire was completed on four occasions, each separated by four weeks.

RESULTS

Postal implementation was the most cost effective method, showed the highest internal consistency of LVQOL items, but resulted in a lower apparent quality of life score than either telephone or in-person interviews (p<0.001). There was no difference in test-retest reliability between the three methods of implementation (p = 0.12). The profile of LVQOL scores showed a trend towards reduced quality of life scores 3 months after the baseline measures, although this was not significant.

CONCLUSION

Posting may be the method of choice for clinical measurement of vision related quality of life. Patients with greater visual impairment were no less likely to complete a questionnaire when implemented by post and there was no apparent bias from other people assisting them. The quality of life measure can occur at any time up to 2 months after low vision rehabilitation for the progressive nature of conditions causing low vision not to cause a decreased baseline score. The LVQOL was shown to be a highly internally consistent and reliable method for measuring quality of life in the visually impaired.

Macular degeneration: do conventional measurements of impaired visual function equate with visual disability?

AIMS

To examine the relation between measures of vision and ability to perform daily living tasks in those visually impaired with macular degeneration.

METHODS

A visual functioning index (daily living tasks dependent on vision: DLTV) was used to evaluate patients' perception of their ability to perform vision dependent tasks. Distance visual acuity, near visual acuity, reading speed, and contrast sensitivity were measured in all patients. In addition, a new measure of reading ability was derived, designated the reading index. This takes into account both the size of the text read and the time to read it and is equivalent to the reading speed in words per minute divided by text size in M.

RESULTS

The reading index was found to show best associations with the majority of items within the DLTV. Stepwise regression identified the combination of reading index and distance visual acuity as having the best associations with DLTV items. The present study also demonstrated that specific levels of vision as measured by acuity, reading index, and contrast sensitivity corresponded with different perceived amounts of difficulty in the performance of daily living tasks.

CONCLUSIONS

This study showed that reading index is valuable in predicting the ability to perform daily living tasks and therefore may be useful in the visual assessment of the visually impaired individual. In addition, this study identified specific levels of vision at which individuals reported different degrees of difficulty in performing daily living tasks.

Creation and testing of a practical visual function assessment for use in Africa: correlation with visual acuity, contrast sensitivity, and near vision in Malawian adults

AIM

To develop and test a practical visual function assessment for use in developing countries.

METHODS

Using focus group discussions and interviews with eyecare workers and low vision specialists in Malawi, 13 questions related to visual characteristics of activities of daily living were designed. Patients presenting to an eye clinic were recruited and interviewed. Visual acuity, near vision, and contrast sensitivity were measured. Analysis sought to determine the degree of correlation between the vision indices and visual function.

RESULTS

The visual function questionnaire was easy to administer. Visual function correlated with visual acuity, contrast sensitivity, near vision, and patient reported visual problem. People with a higher frequency of "not applicable" responses had lower visual function scores. Multivariate modelling revealed that visual acuity and number of questions felt to be applicable were independently associated with visual function. Reducing the questionnaire to nine questions did not affect the degree of correlation with any of the visual indices.

CONCLUSION

The authors' visual function assessment correlates well with different measures of visual acuity. People with reduced vision for a prolonged period may no longer consider doing certain tasks and the number of questions considered appropriate by an individual may be an additional measure of visual function. Assessment of visual function by health workers may be a valuable tool in improving surgical uptake by encouraging both health personnel and patients to recognise that they have difficulties undertaking activities of daily living as well as a measure of monitoring and evaluating cataract outcomes.

Quality of life outcomes following dacryocystorhinostomy: external and endonasal laser techniques compared

AIMS/BACKGROUND. Endonasal laser dacryocystorhinostomy (ELDCR) has recently become established as an alternative technique to conventional external DCR (EXDCR) for relief of epiphora. The aim of this study was to compare quality of life and symptomatic outcomes in patients treated by these two methods. METHODS. A postal questionnaire was sent to 204 ELDCR and 78 EXDCR patients who had undergone surgery under our care more than 6 months previously. The questionnaire included the validated 18-item Glasgow Benefit Inventory (GBI) and 5 further questions addressing ocular symptomatology. RESULTS. Fully completed questionnaires were received from 156 ELDCR and 50 EXDCR patients. Mean GBI scores of +16.8 (ELDCR) and +23.2 (EXDCR) were obtained (Mann-Whitney U test = NS). Ocular symptom scores were +33 (ELDCR) and +54 (EXDCR) (p=0.005). CONCLUSION. Patients undergoing either ELDCR or EXDCR experience significant benefit in their healthcare status as detected by the GBI. There is no significant difference between the scores obtained by the two groups of patients. There were improvements in ocular symptom scores in both groups, with patients who had EXDCR scoring significantly better than the ELDCR group.

Socioeconomic barriers to cataract surgery in Nepal: the South Asian cataract management study

BACKGROUND

Previous studies have shown that, despite an increasing availability of cataract surgery, important socioeconomic barriers exist in the acceptance of surgery in many rural areas of south Asia. Nepal has developed a comprehensive national network of eye hospitals but the surgical coverage for the treatment of cataract blind is still low.

AIMS

To determine the utilisation of cataract surgery and the level of physical and psychosocial impairment and the socioeconomic barriers to surgery in a group of non-acceptors of surgery.

METHODS

Of 319 cataract patients identified in a field screening 96 non-acceptors of surgery were interviewed 1 year after an offer to undergo surgery. The interview included questions on visual function, quality of life, and socioeconomic variables on acceptance of cataract surgery. The quality of life questionnaire was based on the field validated protocol addressing the impact of visual impairment on physical and psychosocial functions. The questionnaire was adapted to the local conditions after pretesting. Data were analysed by degree of visual impairment.

RESULTS

Of 319 cataract patients identified only 45.5% accepted surgery, with men accepting surgery more readily than women (RR = 1.31; 95% CI = 1.04-1.67) because of a significantly greater acceptance of surgery in men in the non-blind group. The acceptance rate was significantly higher in the blind group (RR = 1.74; 95% CI = 1.36-2.22) compared with those patients having impairment of vision and severe loss of vision. Of 96 non-acceptors interviewed only a further 13% accepted surgery after a second counselling. The most frequent reasons given for not accepting surgery were economic (48%) and logistical (44.8%) constraints followed by fear of surgery (33.3%) and lack of time (18.8%). Half of the subjects complained of problems with self care but only 10% needed help for their most basic every day activities. 17.7% said they needed help to visit neighbours and 26% needed help to attend the field or market.

CONCLUSIONS

It was found that in this population with a majority of patients with severe vision loss and blind, even when offered transport and free surgery the utilisation of cataract surgery is below 60%. Medicine tends to be prescriptive based on technological advances that it is able to offer. Medical practice needs to develop a more holistic understanding of the needs of the communities cultivating a greater capability to analyse the role of cultural, social, and economic factors when planning medical services for the population.

Prevalence of blindness and cataract surgery in Shunyi County, China

PURPOSE

To estimate the prevalence of blindness and cataract surgery among older adults in rural China.

METHODS

Cluster sampling was used in randomly selecting men and women aged 50 years or older for visual acuity testing and an eye examination in 28 villages in Shunyi County. The survey, which was carried out in the fall of 1996, was preceded by a pilot study in which operational methods were refined and quality assurance evaluations carried out.

RESULTS

Of 5,555 enumerated subjects > or =50 years of age, 91.5% (5,084/5,555) were examined and 90.9% (5,052/5,555) were tested for visual acuity. In this population, 2.8% (139/5,052) were blind, defined as presenting visual acuity less than 6/60 in both eyes. Blindness was associated with older age and female sex. Cataract was the principal cause of blindness in at least one eye in 48.2% (67/139) of blind people. The ratio of those blind from cataract who were operated on to the those who could have been operated on, cataract surgical coverage, was estimated to be 47.8% (54/113). Cataract surgery was associated with younger age but not sex or education.

CONCLUSIONS

Blindness, particularly blindness related to cataract, continues to be a significant problem among the elderly, especially women, in this population-based sample of rural Chinese. Despite an active eye-care program in Shunyi County, only half of those who might benefit from cataract surgery are receiving it.

Development of a disease specific quality of life questionnaire for patients with Graves' ophthalmopathy: the GO-QOL

AIM

To develop a reliable and valid disease specific quality of life questionnaire (the GO-QOL) for patients with Graves' ophthalmopathy (GO), that can be used to describe the health related quality of life and changes in health related quality of life over time as a consequence of disease and treatment.

METHODS

70 consecutive GO patients (age > 18 years) who were referred for the first time to the combined outpatient clinic of the orbital centre and the department of endocrinology completed the 16 questions of the GO-QOL. Additional information on general quality of life and disease characteristics was obtained. Construct validity and internal consistency of the disease specific questionnaire was determined, based on principal component analysis, Cronbach alphas and correlations with MOS-24, three subscales of the SIP, demographic, and clinical measures.

RESULTS

The a priori expected subdivision of the questionnaire in two subscales, one measuring the consequences of double vision and decreased visual acuity on visual functioning, and one measuring the psychosocial consequences of a changed appearance, was confirmed in the principal component analysis. Both scales had a good reliability and high face validity. Correlations with other measures supported construct validity. Mean scores (range 0-100) were 54.7 (SD 22.8) for visual functioning and 60.1 (24.8) for appearance (higher score = better health).

CONCLUSION

The GO-QOL is a promising tool to measure disease specific aspects of quality of life in patients with GO and provides additional information to traditional physiological or biological measures of health status.

Vision-specific function and quality of life after cataract extraction in south India

PURPOSE

To assess visual and overall patient function after intracapsular (ICCE) and extracapsular (ECCE) cataract extraction in rural South India.

SETTING

Aravind Eye Hospital, Tirunelveli, Tamil Nadu, South India, and the Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore, Maryland, USA.

METHODS

This study evaluated preoperative visual acuity and demographic information and postoperative visual acuity and functional status measures in 71 patients having ECCE with posterior chamber intraocular lens (IOL) placement and 73 patients having ICCE with aphakic spectacle correction at Aravind-Tirunelveli Eye Hospital, Tamil Nadu, India. The principal outcomes assessed were visual acuity; quality-of-life score (possible range 0 to 100%); visual function measurement (possible range 0 to 100%).

RESULTS

Patients in the ECCE group scored 10.17 (P = .0001) points higher than those in the ICCE group on the visual function scale after adjustment for differences in age, sex, level of education, marital status, residence, and type of employment. The ECCE group scored 7.69 points higher on visual function when adjusting for the differences in best corrected visual acuity, which was also better in the ECCE group. In the quality-of-life assessment, 77.1% in the ECCE group and 46.6% in the ICCE group scored 90% or better (OR 3.85; P = .006).

CONCLUSIONS

Patients in rural south India having ECCE with posterior chamber IOL implantation obtained better postoperative visual function, quality of life, and visual acuity than those receiving ICCE with aphakic spectacle correction. These differences, which were not significantly affected by adjustment for age, sex, education, marital status, type of residence, and occupation, indicate that ECCE is clearly superior to ICCE.

The Madurai Intraocular Lens Study. I: A randomized clinical trial comparing complications and vision outcomes of intracapsular cataract extraction and extracapsular cataract extraction with posterior chamber intraocular lens

PURPOSE

The Madurai Intraocular Lens Study (MIOLS) was designed to compare safety, efficacy, and quality of life outcomes after either intracapsular cataract extraction with aphakic glasses (ICCE-AG) or extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/ PC-IOL).

METHODS

The Madurai Intraocular Lens Study was a nonmasked randomized controlled clinical trial conducted at a single hospital. Thirty-four hundred patients with age-related cataracts and having a best-corrected visual acuity less than or equal to 20/120 in the better eye were randomly assigned to either of the two cataract operative procedures. The main clinical outcomes were safety (complication rates) and efficacy (best-corrected visual acuity at 1 year equal to or better than 20/40). In addition, a subset of 1,700 trial participants received questionnaires before surgery, at 6 months after surgery, and at 1 year after surgery to measure visual functioning and vision-related quality of life.

RESULTS

Details of study design, study organization, clinical and quality of life outcome variables, sample size calculations, patient eligibility criteria and recruitment, randomization and masking, participant flow, adherence to follow-up, quality assurance, and statistical methods are presented.

CONCLUSIONS

The Madurai Intraocular Lens Study has sufficient power to detect clinically significant differences between the treatment options. There were no statistically significant differences between the two treatment groups for any of the major study variables at baseline. A high level of quality assurance was maintained throughout the October 1993 to June 1996 study period. The results should be applicable to all settings where the requisite expertise and resources are present.

The Madurai Intraocular Lens Study. III: Visual functioning and quality of life outcomes

PURPOSE

To compare the effects of extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/PC-IOL) vs intracapsular cataract extraction with aphakic glasses (ICCE-AG) on everyday visual functioning and quality of life.

METHODS

In a nonmasked randomized controlled clinical trial, 3,400 bilateral vision-impaired patients, aged 40 to 75 years, with operable cataract were randomly assigned to receive one of the two treatment options. One half in each group were randomly selected for interviewer administration of visual functioning and quality of life questionnaires before surgery and at 6 and 12 months after surgery.

RESULTS

Both ICCE-AG and ECCE/PC-IOL produced dramatic improvements in visual functioning and quality of life scores. Patients receiving ECCE/PC-IOL reported larger beneficial changes than did those receiving ICCE-AG, compatible with additional beneficial effects of a moderate magnitude for visual functioning and of a smaller beneficial magnitude for quality of life. All between-group differences were highly statistically significant (P < .00001). The additional benefits of ECCE/PC-IOL are not explained by visual acuity differences. A higher proportion of patients in the ICCE-AG group reported problems on a vision problem checklist at 6 months (more than 50%) than did patients in the ECCE/PC-IOL group (approximately 30%).

CONCLUSIONS

In this developing-country setting, ICCE-AG and ECCE/PC-IOL were associated with substantial benefits in improved everyday vision function and vision-related quality of life. Patients who received ECCE/PC-IOL reported greater benefits and fewer problems with vision than did patients who received ICCE-AG.

Peters' anomaly

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