Development and Evaluation of a Chinese Version of the Adult Strabismus Questionnaire (AS-20)

Health-Related Quality of Life in Adult Patients with Strabismus-Translation and Psychometric Testing of the Adult Strabismus Questionnaire (AS-20) into Finnish

(1) Strabismus has an impact on individuals' health-related quality of life. The impact should be assessed with valid patient-reported outcome measures such as the Adult Strabismus Questionnaire (AS-20). The AS-20 was further refined using a Rasch analysis for the American population. The aims of the study were to translate and culturally adapt the AS-20 into Finnish and to evaluate the psychometric properties of the Finnish AS-20. (2) The guidelines of the Professional Society for Health Economics and Outcomes Research steered the process and four items were added from the original data as Finnish additions. The construct and convergent validity and internal consistency were evaluated via psychometric testing for three potential Finnish AS-20 structures. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was applied. (3) The participants (n = 137) reported that the translation was clear and understandable. All structures showed high reliability and internal consistency as measured using Cronbach alpha values. The convergent validity assessed using Spearman's correlation coefficients between the structures and one item of Satisfaction with Life Scale indicated very low to moderate positive correlations. The construct validity evaluated using a confirmatory factor analysis revealed the refined AS-20 structure to be satisfactory. (4) The refined AS-20 can be used in clinical practice and research, but further validation is recommended.

Adults with Longstanding Strabismus: Psychosocial and Functional Impacts and Reasons behind Surgery Delay

Purpose

The aims of the study were to determine the reasons behind surgical correction delay in adult patients with strabismus, reveal motivations for seeking treatment, and study the psychosocial and functional impacts of strabismus on patients using an Arabic version of the Adult Strabismus-20 (AS-20) questionnaire. Methods and Patients. This study included 79 patients aged ≥18 years and had strabismus for at least one year prior to surgical correction and 40 controls without known visual defects. After a comprehensive ophthalmic exam during their preoperative visit, a validated questionnaire was administered to patients to collect sociodemographic data, reasons for surgery delay, and motivations for seeking treatment now. A translated version of the AS-20 questionnaire was then presented to patients and controls. Total AS-20 (and its subscales: psychosocial and function) scores were calculated and analyzed. All relationships between sociodemographic characteristics, the onset of deviation, presence of diplopia, type and size of deviation, and the changes in the scores of AS-20 (and its subscales) were investigated.

Results

A total of 79 adult patients with strabismus (cases) and 40 subjects with normal vision (control group) were included in this study. The mean age (SD) was 34.10 (11.5) years for cases (range: 18–61) and 34.20 (11.2) years for controls (range: 18–65) (p=0.964). About half (55.7%, n = 44) of the patients were males compared to (57.5%, n = 23) of the controls. The reasons for strabismus surgery delay reported by the patients were the following: surgery was not offered by an ophthalmologist (35.4%), surgery was offered but declined by the patient due to fear from surgical complications (22.8%), nonaffordability (17.7%), surgery was offered but refused because patients thought they were too old for surgery or patient was not bothered by appearance (15.2%), and patient never sought care (8.9%). The reasons for seeking surgical treatment after this delay were as follows: for cosmetic issues (27.8%), a better understanding of strabismus surgery and its potential complications (20.3%), pressure from family and friends (16.5%), improved economic status (13.9%), relationship/marriage prospects (13.9%), and to improve chances of getting a job (7.6%). When compared to control, patients have significantly lower mean scores of total AS-20 (50.57 vs. 88.01) and its psychosocial (49.59 vs. 87.84) and functional (51.55 vs. 88.19) subscales. AS-20 total score was significantly lower among females and in patients with large deviation size (>25 PD). The psychosocial subscale of AS-20 was significantly lower in females, patients with younger age of onset, and those with large deviation size (>25 PD). Female gender, large deviation size, vertical deviation, and having diplopia correlated significantly with a lower functional score.

Conclusion

Strabismus has a profound psychosocial and functional impact on affected individuals, especially females and patients with large deviation sizes. Many adult patients with strabismus tend to delay surgical correction; most of these delays could be avoided by better public education, increased awareness among health care providers, and changing health insurance policies to cover the costs of strabismus surgery.

Factors influencing the self-reported sense of deviation in adults with successful surgical outcomes for strabismus

BACKGROUND

To determine whether a sense of deviation remains in adults with successful motor alignment who fulfil diplopia criteria after surgery and to examine the factors associated with this judgement.

METHODS

This was a retrospective study. Adult patients defined as having a successful outcome based on more than 1 year of post-operative follow-up visits were included in the study. The sense of deviation was determined at the last visit. Pre- and post-operative deviation and characteristics including age, gender, education level, occupation, diagnosis, size of deviation, extraocular movement (EOM), binocular function, and health-related quality of life (HRQOL) were recorded.

RESULTS

In total, 22 (24%) of the 91 adults with successful surgical outcomes reported a sense of deviation. No significant differences were noted between subjects with and without a sense of deviation regarding patient demographics, pre- and post-operative deviation, changes in deviation, sensory fusion or EOM. Subjects with a sense of deviation had an increased prevalence of and larger post-operative vertical deviation, poorer stereo function, and lower HRQOL scores than those with no sense of deviation. The presence of post-operative vertical deviation was associated with a sense of deviation.

CONCLUSIONS

Approximately one-fourth (24%) of adults defined as having successful surgical outcomes who still had a sense of deviation exhibited worse stereo function, higher vertical deviation size and lower HRQOL scores. The presence of 3 to 5 prism dioptres(pd) of vertical deviation would be the main factor associated with a sense of deviation post-operatively.

Development of a conceptual model regarding quality of life in Chinese adult patients with strabismus: a mixed method

Background

Substantial challenges have been reported in China in terms of the large number of adult patients with strabismus and their poor quality of life. Quality of life is a cultural concept that varies according to personal feelings and perceptions, and it is influenced by physical, psychological and social factors. However, to date, there has been no mixed-method research of the quality of life of Chinese adult patients with strabismus, and no conceptual model has been reported. This study aimed to utilize mixed methods to explore the influence of strabismus on health-related quality of life in Chinese adult patients and to develop a conceptual model.

Methods

Thirty adult patients with strabismus from three tertiary hospitals in China participated in the interview. In-depth one-to-one interviews were semi-structured and addressed strabismus-related symptoms and the impacts on the participants’ quality of life. Transcripts were analysed to identify themes. A self-designed questionnaire was distributed to 448 patients, 437 of whom returned valid questionnaires. Descriptive statistics and x² test were conducted.

Results

Five themes were revealed regarding the impact of strabismus on patient quality of life: appearance, daily activities, personal development, social interaction, and emotions. In the survey, the top three symptoms (n ≥ 70%) rated by the participants were monocular vision, eye fatigue and physical discomfort. Compared to those without diplopia, the patients who suffered diplopia more often reported experiencing the symptoms of blurred vision, monocular vision, physical discomfort, eye fatigue, cannot estimate depth well and increasing deviation size (all p < 0.05).

Conclusions

This study is the first to examine quality of life among Chinese strabismus patients using both qualitative and quantitative methods and proposing a conceptual model. Symptom burden and appearance were the two original reasons for the decreased quality of life, and they were also the triggers for strabismus patients to visit clinics and undergo surgery. The interventions to treat symptoms burden should be different between patients with and without diplopia.

Investigation of factors associated with the success of adult strabismus surgery from the patient's perspective

PURPOSE

To explore factors that influence the success of adult strabismus surgery based on health-related quality of life (HRQOL) criteria.

METHODS

The HRQOL aspect of strabismus surgery was assessed using the Adult Strabismus 20 (AS-20) questionnaire. Adult patients (≥16 years of age) undergoing strabismus surgery between 2014 and 2016 were identified using a treatment register. Pre- and postoperative AS-20 scores were calculated. HRQOL surgical success was defined as a pre- to postoperative change in AS-20 score exceeding previously published 95% limits of agreement. Any relationship between demographic factors (sex, age, and socioeconomic status), presence or absence of diplopia, type and magnitude of deviation, and change in deviation size with HRQOL success was investigated.

RESULTS

A total of 87 patients were included (mean age, 47 years; 53% female). Nondiplopic patients showed significantly lower pre- and postoperative scores on the AS-20 psychosocial subscale compared to diplopic patients. Of 87 surgeries, 54 (62%) were classified as successful based on HRQOL criteria. Multiple logistic regression analysis showed only lower socioeconomic status to be significantly associated with a higher rate of HRQOL success (P = 0.04).

CONCLUSIONS

Strabismic patients with a lower socioeconomic status are more likely to achieve HRQOL success following surgery. We also show that nondiplopic patients have more psychosocial concerns than those with diplopia and that this disparity persists even after strabismus surgery.

The Development of the Chinese Intermittent Exotropia Questionnaire

PURPOSE

The Intermittent Exotropia Questionnaire (IXTQ) is a child, proxy, and parent report of health-related quality of life specific to children with intermittent exotropia (IXT). The present study aimed to develop a Chinese-language version of the IXTQ (CIXTQ) and evaluate its validity and reliability when used in Chinese IXT children and their parents.

METHODS

The IXTQ was translated into Chinese. One hundred seventy-five IXT children (2 to 17 years old) and 151 orthotropic control children (2 to 17 years old) along with one of their parents were recruited. Children 5 to 17 years old completed the 5- to 7-year-old or the 8- to 17-year-old child questionnaire of the CIXTQ according to their age. Parents of all children (2 to 17 years old) completed the proxy and parent questionnaires of the CIXTQ. Psychometric properties of the CIXTQ were examined for floor and ceiling effects, construct validity, item-internal consistency, discriminative validity, Cronbach α coefficient and test-retest reliability.

RESULTS

No items were found to have strong floor or ceiling effects. Principal component analysis identified that the CIXTQ had a similar structure to the original English version. The median scores of each questionnaire in the CIXTQ among children with IXT and their parents were significantly lower than those among control subjects (P < .001). Cronbach α coefficients ranged from 0.869 to 0.931, and test-retest reliabilities ranged from 0.898 to 0.981, for each questionnaire in the CIXTQ.

CONCLUSIONS

The CIXTQ is a useful tool to evaluate the influence of IXT on health-related quality of life among Chinese IXT children and their parents.

Long-Term Quality of Life in Adult Patients with Strabismus after Corrective Surgery Compared to the General Population

PURPOSE

To evaluate the status of and factors associated with long-term health-related quality of life (HRQOL) in adult patients with strabismus following corrective surgery.

METHODS

Prospective cross-sectional study. A total of 122 adults who underwent corrective surgery and were followed up for at least 1 year were recruited. Pre- and post-operative HRQOL were evaluated using the Chinese version of the Adult Strabismus 20 (AS-20). Demographics and clinical characteristics were recorded. Eighty-nine age-matched, normal individuals without a history of strabismus were recruited as a control group.

RESULTS

AS-20 scores improved significantly in the psychosocial subscale and total scale after surgery for all122 patients, but not in the function subscale. HRQOL was better in the successful cases than in the non-successful cases (p<0.005). Subjects who recovered stereo function had better HRQOL than those who did not (p<0.01). Compared to the control population, the patients had poorer HRQOL post-operatively, with only approximately 30% of the subjects having scores within the normal threshold scores. The self-sense of a lack of ocular deviation and a successful surgical outcome were significant factors associated with post-operative HRQOL status.

CONCLUSIONS

HRQOL, as evaluated by AS-20 scores, improved in the patients after surgery but was worse than that in the general population. Successful surgical outcomes and a sense of good alignment were the main factors that correlated with increased post-operative HRQOL. Positive assessments of surgical results by patients may benefit post-operative HRQOL.

Evaluation and validity of the Danish version of the Adult Strabismus Questionnaire AS-20

Purpose

Assessing health-related quality of life in patients with strabismus is important in evaluating the clinical benefits of strabismus treatment. The purpose of this study was to translate the Adult Strabismus Quality of Life Questionnaire (AS-20) into Danish and evaluate its reliability and validity in adult patients with strabismus in Denmark.

Methods

The AS-20 was translated into Danish in accordance with standard international adopted methods. We presented the questionnaire to 64 adults with strabismus and to 13 non-strabismic adult controls. We tested the reliability of the Danish version by reassuring test–retest reliability, estimated the internal consistency, and analyzed the validity (discriminatory power) of the questionnaire by comparing patient scores with scores from control individuals.

Results

The Danish AS-20 produced high level of internal consistency (Cronbach’s α values) for both subscales (psychosocial: 0.95 and functional: 0.85). We found good discriminatory power of the AS-20. The patients scored significantly lower not only on AS-20 composite score (median =63, interquartile range [IQR] =44–79) compared to healthy individuals (median =98, IQR =93–100) (P<0.0001) but also on all individual questions in both subscales (psychosocial: 1–10 and functional: 11–20).

Conclusion

The Danish version of AS-20 shows high reliability and validity, and in our opinion, AS-20 is therefore a suitable instrument for evaluating self-perceived psychosocial and functional influence of strabismus.

Rasch Analysis of the Adult Strabismus Quality of Life Questionnaire (AS-20) among Chinese Adult Patients with Strabismus

Background

The impact of strabismus on visual function, self-image, self-esteem, and social interactions decrease health-related quality of life (HRQoL).The purpose of this study was to evaluate and refine the adult strabismus quality of life questionnaire (AS-20) by using Rasch analysis among Chinese adult patients with strabismus.

Methods

We evaluated the fitness of the AS-20 with Rasch model in Chinese population by assessing unidimensionality, infit and outfit, person and item separation index and reliability, response ordering, targeting and differential item functioning (DIF).

Results

The overall AS-20 did not demonstrate unidimensional; however, it was achieved separately in the two Rasch-revised subscales: the psychosocial subscale (11 items) and the function subscale (9 items). The features of good targeting, optimal item infit and outfit, and no notable local dependence were found for each of the subscales. The rating scale was appropriate for the psychosocial subscale but a reduction to four response categories was required for the function subscale. No significant DIF were revealed for any demographic and clinical factors (e.g., age, gender, and strabismus types).

Conclusion

The AS-20 was demonstrated by Rasch analysis to be a rigorous instrument for measuring health-related quality of life in Chinese strabismus patents if some revisions were made regarding the subscale construct and response options.

Psychometric properties of the Chinese version of the Amblyopia and Strabismus Questionnaire (ASQE)

Background

Strabismus and amblyopia are known to cause visual dysfunction, self-image disorders, difficulty in seeking employment and social and emotional barriers. These factors can have a serious and detrimental effect upon the patients’ health-related quality of life (HRQOL). Presently, a condition-specific questionnaire is not available for assessing the HRQOL in Chinese patients. This study developed a Chinese version of the Amblyopia and Strabismus Questionnaire (ASQE) and tested its reliability and validity in Chinese adult strabismus patients.

Methods

Chinese strabismus adults, adults with normal vision and patients with a variety of other eye diseases completed the Chinese version of the ASQE. Reliability was established by Cronbach’s alpha and test-retest. Validity was evaluated by content, construct, criterion-related, convergent and discriminative validities.

Results

A total of 202 adult strabismus patients with or without amblyopia, 100 visually normal adults, and 100 patients with other eye diseases (excluding strabismus and amblyopia) participated in this study. Using principal components analysis, six domains were extracted, with a content validity of 0.91. Four items were deleted giving final total of 22 items in the questionnaire. The total score of the ASQE was significantly correlated to the Adult Strabismus Questionnaire (AS-20) (r = 0.642, P < 0.01). The median scores for the adult strabismus patients were significantly lower (worse HRQOL) compared with visually normal adults (66.32 vs. 92.71; P < 0.001) and patients with other eye diseases (66.32 vs. 79.50; P < 0.001) thus demonstrating good discriminative validity for the questionnaire. The Cronbach’s alpha coefficient for internal consistent reliability was 0.887 and the test-retest reliability was 0.946. The mean total score of the ASQE was 65.85 (SD = 15.32) and the domain ‘social contact and appearance’ recorded the lowest mean score 43.78 (SD = 13.92) in strabismus patients.

Conclusions

The revised 22-item Chinese version of the ASQE showed good psychometric properties. It is suggested that this questionnaire provides a potentially useful measurement tool in clinical or research programs involving Chinese strabismus patients with or without associated amblyopia.

Measuring Health-Related Quality of Life in Strabismus: A Modification of the Adult Strabismus-20 (AS-20) Questionnaire Using Rasch Analysis

Purpose

To evaluate the psychometric properties of the Adult Strabismus-20 (AS-20)- a health-related quality of life (HRQoL) questionnaire in adults with strabismus, and if flawed, to revise the AS-20 and its subscales creating valid measurement scales.

Methods

584 adults (meanage, 27.5 years) with strabismus were recruited from an outpatient clinic at a South Indian tertiary eye care centre and were administered the AS-20 questionnaire.The AS-20 was translated and back translated into two Indian languages. The AS-20 and its two 10-item subscales – ‘psychosocial’ and ‘function’were assessed separately for fit to the Rasch model, including an assessment of the rating scale, unidimensionality (by principal components analysis), measurement precision by person separation reliability, PSR, targeting, and differential item functioning (DIF; notable > 1.0 logits).

Results

Response categories were not used as intended, thereby, required re-organization and reducing their number from 5 to 3. The AS-20 had adequate measurement precision (PSR = 0.87) but lacked unidimensionality; however, deletion of the six multi-dimensionality causing items and an additional three misfitting items resulted in 11-item unidimensional questionnaire (AS-11). Two items failed to satisfy the model expectations in the ‘psychosocial’ subscale and were deleted – resulting in an 8-item unidimensional scale with adequate PSR (0.81) and targeting (0.23 logits). One item misfit in the ‘function’ subscale and was deleted—resulting in a 9 item Rasch-revised unidimensional subscale with acceptable PSR (0.80) and targeting (0.97 logits).None of the items displayed notable DIF by age, gender and level of education.

Conclusions

The AS-11 and its two Rasch-revised subscales – 8-item psychosocial and 9-item function subscale may be more appropriate than the original AS-20 and its two 10-item subscales for use as unidimensional measures of HRQoL in adults with strabismus in India. Further work is required to establish the validity of the revised rating scale.