1
COMPARISON OF TWO HEALTH RELATED QUALITY OF LIFE QUESTIONAIRES IN MALAY CHILDREN WITH
STRABISMUS AND THEIR PARENT PROXY
BY
DR TAN JIN POI
(MBBch BAO, National University of Ireland)
DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER
OF MEDICINE (OPHTHALMOLOGY)
SCHOOL OF MEDICAL SCIENCES UNIVERSITI SAINS MALAYSIA
2015
2
DISCLAIMER
I hereby certify that the work in this dissertation is my own except for the quotations and summaries which have been duly acknowledged.
Date : 26th May 2015 ………..
Tan Jin Poi PUM 0148/ 09
3
ACKNOWLEDGEMENT
I would like to express my deepest gratitude and appreciation to my supervisor, Professor Dr. Shatriah Ismail. You have been an inspiring mentor, a supportive friend and a respectful model, all at the same time to me. I cherish the full effort, your kind patience and precious time that you have given me throughout this study and provided me generously stimulating suggestions and aspiring encouragement as well. It is undeniable that you have played such important role in maintaining my progress in track and making this study possible. Thank you for all the experience, the knowledge, and the unfailing encouragement that you have ever so ready to provide and share. I will forever cherish this experience.
Furthermore, I would also like to acknowledge with much appreciation to Miss Norsuhana Mohd. Noor, Staff Nurse Sarimah Samsudin, Staff Nurse Che Hasmah Che Said, Miss Norhaniza Harun. All of you played a crucial role in the process of my data collection. I would never have been able to finish my dissertation if it wasn’t for your unselfish dedication. It has been such a wonderful pleasure working with all of you.
A warm thanks to lecturer Dr Sarimah Abdullah and Miss Tengku Mardhiah. Both of you have patiently answered all my qualms on statistical issues and jargons. I deeply appreciate the time that both of you are willing to allocate despite of your busy schedule. Your constructive advices were very helpful indeed.
Most importantly, I am in debt to my loving and supportive family. You have been my comforters, always welcoming me and providing me a place of refuge whenever I feel
4
overwhelmed with the work load and when I was unwell. Your sacrifice in nursing me back to health has deeply touched my heart and sustained me throughout my career. All that you have done unconditionally had changed my view in life. No words can express my gratitude to all of you.
5
TABLE OF CONTENTS
PAGE
TITLE 1
DISCLAIMER 2
ACKNOWLEDGEMENT 3
TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES
ABSTRAK (BAHASA MALAYSIA) ABSTRACT (ENGLISH)
5 10 12 13 16
CHAPTER 1: INTRODUCTION 19
1.1 Strabismus
1.1.1 Prevalence of strabismus 1.1.2 Functional effects of strabismus 1.1.3 Psychosocial effects of strabismus 1.2 Health Related Quality of Life Questionnaires
1.2.1 Intermittent Exotropia Questionnaires (IXTQ) 1.2.2 Adult Strabismus-20 (AS-20) Questionnaires
20 20 24 26 32 33 35
1.3 Rationale of Study 36
CHAPTER 2: STUDY OBJECTIVES 2.1 General objective
2.2 Specific objectives
37 38 38
6 CHAPTER 3: METHODOLOGY
3.1 Study design
3.2 Population, place of study and duration of study 3.2.1 Study population
3.2.2 Place of study 3.2.3 Duration of study 3.3 Sampling and sample size 3.3.1 Sampling method 3.3.2 Sample size calculation
3.3.2.1 Sample size calculation for objective one 3.3.2.2 Sample size calculation for objective two 3.4 Selection criteria
3.4.1 Inclusion criteria
3.4.1.1 Inclusion criteria for child 3.4.1.2 Inclusion criteria for parent 3.4.2 Exclusion criteria
3.4.2.1 Exclusion criteria for child 3.4.2.2 Exclusion criteria for parent 3.5 Ethical approval
3.6 Financial support 3.7 Definition of terms
3.7.1 Strabismus / Tropia 3.7.2 Exotropia
3.7.3 Esotropia
3.7.4 Health Related Quality Of Life (HRQOL)
39 40 40 40 40 40 41 41 42 42 42 43 43 43 43 44 44 44 45 45 46 46 46 46 46
7 3.7.5 Likert type scale answer 3.7.6 Malay (Melayu)
3.7.7 Intermittent Exotropia Questionnaire (IXTQ) 3.7.8 Adult Strabismus-20 (AS-20) Questionnaire 3.7.9 Cronbach’s alpha coefficient
3.8 Study tools and instruments 3.9 Details of methodology
3.9.1 Phase 1: From the Questionnaire’s Translation to the Pretest
3.9.2 Recruitment of patients 3.9.3 Orthoptic assessment
3.9.4 Anterior segment and posterior segment examination 3.9.5 Written consent
3.9.6 Sampling procedures 3.10 Methods to minimize study error 3.11 Statistical analysis
47 47 47 47 48 49 57 57
59 59 59 60 60 62 63
CHAPTER 4: RESULTS
4.1 Demographics for phase one 4.1.1 Demographic data
4.1.1.1 Age distribution 4.1.1.2 Gender distribution 4.1.1.3 Parents distribution 4.1.2 Clinical characteristics
4.1.2.1 BCVA
64 65 65 65 66 67 68 68
8 4.1.2.2 Types of strabismus
4.2 Reliability Analysis of the translated IXTQ and AS-20 Questionnaires
4.3 Demographics for phase two 4.3.1 Demographic data
4.3.1.1 Age distribution 4.3.1.2 Gender distribution
4.3.1.3 Parents or guardians distribution 4.3.2 Clinical characteristics
4.3.2.1 BCVA
4.3.2.2 Types of strabismus
4.4 Malay version of IXTQ and AS-20 in children
4.4.1 Mean scores of Malay version of IXTQ in Children
4.4.2 Mean scores of Malay version of AS-20 in Children
4.4.3 Comparison between Malay version of IXTQ and AS-20 Questionnaires in Children
4.5 Malay version of IXTQ and AS-20 in parent proxy
4.5.1 Mean scores of Malay version of IXTQ in parent proxy 4.5.2 Mean scores of Malay version of AS-20 in parent proxy
4.5.3 Comparison between Malay version of IXTQ and AS- 20 Questionnaires in children and parent proxy
4.6 Comparison between the children and their parent proxy
69 70
71 71 71 72 73 74 74 75 76 76
78
80
81 81 83 85
86
9
4.6.1 Comparison between Malay version of IXTQ in children and proxy
4.6.2 Comparison between Malay version of AS-20 in children and proxy
86
88
CHAPTER 5: DISCUSSION
5.1 Evaluation of content validity of Malay version of IXTQ and AS-20 questionnaires
5.2 Total mean score of IXTQ and AS-20 in Malay children with strabismus and their parent proxy
5.3 Comparison of mean scores between the Malay version of IXTQ and the Malay version of AS-20 questionnaires in the children and parent proxy
5.4 Comparison of mean scores between the children and their parent proxy
5.5 Limitations and recommendations
CHAPTER 6: CONCLUSION
CHAPTER 7: REFERENCES
CHAPTER 8: APPENDICES
89 90
91
99
104
110
111
113
124
Appendix A: Flow chart of the study 125
Appendix B: Patient consent form (English and Malay Versions) 127
Appendix C: Data collection form 129
Appendix D: Patient information sheet (English and Malay Versions) 143
10
Appendix E: Ethical approval 155 LIST OF TABLES
PAGE Table 3.1 Items in the IXTQ concerning the subject’s eye 51 Table 3.2 Items in the AS-20 concerning the subject’s eye 52 Table 4.1 Age distribution for the respondents in the phase one study 65 Table 4.2 Distribution of parents in the phase one study 67 Table 4.3 BCVA distribution in phase one study population 68 Table 4.4 Types of strabismus in phase one study population 69
Table 4.5 Reliability statistic 70
Table 4.6 Distribution of demographic characteristics for the respondents 71
Table 4.7 Distribution of the parents 73
Table 4.8 BCVA 74
Table 4.9 Types of Strabismus 75
Table 4.10 Total mean score and subscale mean scores of IXTQ in Children 76 Table 4.11 Individual item mean scores of IXTQ in Children 77 Table 4.12 Total mean score and subscale mean scores of AS-20 in Children 78 Table 4.13 Individual item mean scores of AS-20 in Children 79 Table 4.14 Comparison between mean scores of Malay version of IXTQ and 80 AS-20 Questionnaires in children
Table 4.15 Total mean score and subscale mean scores of IXTQ in proxy 81 Table 4.16 Individual item mean scores of IXTQ in parent proxy 82 Table 4.17 Total mean score and subscale mean scores of AS-20 in proxy 83 Table 4.18 Individual item mean scores of AS-20 in parent proxy 84 Table 4.19 Comparison between total mean score of IXTQ and AS-20 85
11 Questionnaires in parent proxy
Table 4.20 Comparison between mean scores of Malay version of Child 86
IXTQ and Proxy IXTQ
Table 4.21 Comparison between individual item mean scores of Malay 87 version of Child IXTQ and Proxy IXTQ
Table 4.22 Comparison between total mean score of Malay version of 88 Child AS-20 and Proxy AS-20 Questionnaires
Table 4.23 Comparison between individual item mean scores of Malay 89 version of Child AS-20 and Proxy AS-20 Questionnaires
12
LIST OF FIGURES
PAGE
Figure 3.1 Slit Lamp Biomicroscope 53
Figure 3.2 Binocular indirect ophthalmoscope 53
Figure 3.3 Goldmann Applanation Tonometer 53
Figure 3.4 Airpuff tonometer 53
Figure 3.5 a) Topical Phenylephrine 54
b)Topical Tropicamide c) Topical Cyclopentolate d) Topical Proparacaine
e) Fluorescein Sodium paper strip
Figure 3.6 Snellen Chart 54
Figure 3.7 Kay pictures acuity test 55
Figure 3.8 Smart system optosmart 55
Figure 3.9 Fixation target 55
Figure 3.10 Transparent occluder 55
Figure 3.11 Block prism set 56
Figure 3.12 Frisby stereotest 56
Figure 3.13 Retinoscopy trial lenses and retinoscope 56
Figure 3.14 Retinoscope 56
Figure 4.1 Phase One Study - Gender distribution 66
Figure 4.2 Gender Distribution 72
13
PERBANDINGAN DI ANTARA DUA JENIS BORANG SOAL SELIDK KUALITI KEHIDUPAN DI KALANGAN KANAK-KANAK MELAYU DENGAN JULING DAN PROKSI IBU BAPA MEREKA
ABSTRAK
Pengenalan: Juling merupakan satu penyakit mata yang boleh menyebabkan masalah-masalah kosmetik, fungsi dan psikososial. Penilaian Kualiti Kehidupan Berkaitan dengan Kesihatan (HRQoL) semakin diiktirafkan sebagai satu faktor penting dalam rawatan juling dan merupakan satu instrumen yang penting dalam bidang penyelidikan klinikal. Tetapi, tidak banyak alat penilaian HRQoL juling yang khusus, terutamanya untuk kanak-kanak dan dalam pengetahuan kami, tidak ada penerjemahan Bahasa Malaysia untuk soal selidik juling juga. Dalam kajian kami, IXTQ dan AS-20 versi Inggeris telah diterjemahkan kepada Bahasa Malaysia dan mencapai pengesahan linguistik. Kami harap dua-dua borang soal selidik ini dapat diperkenalkan ke dalam amalan klinikal kami. Selain itu, kajian ini juga membandingkan borang soal selidik IXTQ dan AS-20 versi Melayu yang baru di kalangan kanak-kanak Melayu dengan juling dan proksi ibu bapa mereka.
Objektif: Untuk membandingkan dua jenis borang soal selidik kualiti kehidupan (HRQoL) dalam aspek fungsi dan psikososial di kalangan kanak-kanak Melayu dengan juling dan proksi ibu bapa mereka.
Metodologi: Soal selidik telah diterjemahkan dari Inggeris ke Bahasa Malaysia sebelum diberikan kepada 30 kanak-kanak Melayu dengan juling dan ibu bapa mereka untuk menentukan kebolehpercayaan konsistensi dalaman. Ujian alfa Cronbach telah digunakan. Ini diikuti oleh kajian keratan rentas komparatif yang telah dijalankan di
14
Klinik dan Wad Oftalmologi, Hospital Universiti Sains Malaysia dari Jun 2012 hingga Jun 2014. Seramai 57 kanak-kanak Melayu berusia 5 hingga 17 tahun dan ibu bapa telah dikumpulkan untuk kajian ini. Kanak-kanak dan ibu bapa kemudiannya diminta untuk mengisi borang soal selidik IXTQ dan AS-20 versi Melayu. Kanak-kanak dan ibu bapa diberikan arahan lisan dan bertulis yang mudah oleh personel terlatih dan diminta untuk menjawab berasaskan pengalaman mereka bulan sebelumnya. Soal selidik terdiri daripada jawapan skala 5 titik jenis Likert. Jumlah purata skor, purata skor sub-skala fungsi dan psikososial telah dikira dan dibandingkan di antara dua-dua soal selidik.
Keputusan: Penilaian konsistensi dalaman untuk semua soal selidik versi Melayu yang baru diterjemahkan kecuali IXTQ Kanak-kanak melebihi nilai alfa 0.90.
Nilai alfa untuk AS-20 Kanak-kanak ialah 0.909, 0.912 untuk IXTQ Proksi, 0.948 untuk AS-20 Proksi dan 0.651 untuk IXTQ Kanak-kanak. Terdapat perbezaan yang signifikan dalam jumlah purata skor dan purata skor sub-skala fungsi di antara kedua-dua IXTQ dan AS-20 di kalangan kanak-kanak Melayu dengan juling (p < 0.001). Tetapi, didapati tiada perbezaan yang signifikan antara purata skor sub-skala psikososial dua-dua soal selidik dalam kanak-kanak (p = 0.122). Semua skor soal selidik IXTQ dan AS-20 Proksi mempunyai perbezaan signifikan (p < 0.05). Kajian kami juga mencatatkan skor yang lebih rendah dalam soal selidik IXTQ dibandingkan dengan skor soal selidik AS-20.
Kesimpulan: Jumlah purata skor dan purata skor sub-skala fungsi adalah lebih tinggi dalam soal selidik AS-20 versi Melayu berbanding dengan IXTQ versi Melayu dalam kanak-kanak Melayu dengan juling. Perbezaan ini juga didapati signifikan.
Tetapi, perbezaan dalam purata skor sub-skala psikososial di antara dua soal selidik
15
dalam kanak-kanak didapati tidak signifikan. Untuk ibu atau bapa atau penjaga proksi kanak-kanak Melayu dengan juling, didapati semua purata skor adala lebih rendah di soal selidik IXTQ versi Melayu berbanding dengan AS-20 versi Melayu Proksi.
Perbezaan ini didapati signifikan.
16
COMPARISON OF TWO HEALTH RELATED QUALITY OF LIFE QUESTIONAIRES IN MALAY CHILDREN WITH STRABISMUS AND THEIR PARENT PROXY
ABSTRACT
Introduction: Strabismus is an eye condition associated with cosmetic, functional and psychosocial circumstances. Evaluation of Health Related Quality of Life (HRQoL) is increasingly recognized as an important factor in strabismus management and a crucial tool for clinical research. However, there are not many strabismus-specific HRQoL assessment tools, especially for children and to our knowledge, no Malay translation for strabismus specific questionnaires. The English versions of IXTQ and AS-20 questionnaires were translated into Malay language and achieved linguistic validation in our study in a hope to apply the questionnaires into our clinical practice. This study also compared the newly developed Malay version of IXTQ and AS-20 HRQoL questionnaires in Malay children with strabismus and their parent proxy.
Objective: To compare two health related quality of life (HRQoL) questionnaires for functional and psychosocial aspects in Malay children with strabismus and their parent proxy.
Methodology: The questionnaires were translated forward and backward before they were administered to 30 Malay children with strabismus and their parents to determine the internal consistency reliability. The test for Cronbach’s alpha was performed. This was then followed by a comparative cross sectional study conducted in Ophthalmology Clinic and Ward, Hospital Universiti Sains Malaysia from June 2012
17
until June 2014. A total of 57 Malay children aged 5 to 17 years and their parents were recruited for this study. The children and their parents were then asked to complete the translated Malay version of IXTQ and the AS-20 questionnaires. Children and their parents were given simple verbal and written instructions by a trained personnel and asked to base their responses on their experiences over the previous month.
Questionnaires consist of 5 point Likert type scale answer. The total mean scores, functional subscale scores and psychosocial scores were calculated and compared between both questionnaires.
Result: The evaluation of the internal consistency for all our newly translated Malay version questionnaires except for Child IXTQ exceeded an alpha of 0.90. The alpha value was 0.909 for Child AS-20, 0.912 for Proxy IXTQ, 0.948 for Proxy AS-20 and 0.651 for Child IXTQ. There was a significant difference noted in the total mean scores and the functional subscale mean scores between both IXTQ and AS-20 questionnaires in the Malay children with strabismus (p < 0.001). There was no significant difference between the psychosocial subscale mean scores of the two questionnaires in the children (p = 0.122). In the comparison between the Proxy IXTQ and AS-20, there was a significant difference noted in the total mean scores, the functional subscale and the psychosocial subscale mean scores between both questionnaires (p < 0.05). All the scores in AS-20 questionnaires are higher when compared to the scores from all IXTQ.
Conclusion: The total mean score and functional subscale mean score were significantly lower in the Malay version of IXTQ compared to the Malay version of AS- 20 in the Malay children with strabismus. There was no significant difference in the
18
psychosocial subscale mean score between the two questionnaires in the children. The total mean score, functional and psychosocial subscale mean score were significantly lower in the Malay version of IXTQ compared to the Malay version of AS-20 questionnaires in the parent of Malay children with strabismus.
19
Chapter 1
Introduction
20 1.0 INTRODUCTION
1.1 Strabismus
1.1.1 Prevalence of Strabismus
Strabismus, also known as heterotropia or squint, is defined as misalignment of the eyes. In other words, the eyes do not point in the same direction. It is an eye condition with cosmetic and functional circumstances (Carlton et al., 2008). Carlton et al performed a systemic literature review in 2008 on the prevalence and natural history, the screening methods used, effectiveness of treatment options, and health- related quality of life issues relating to amblyopia and strabismus. They also reported that if strabismus is left untreated, it would persist into adulthood.
Few population-based studies have reported the prevalence of strabismus in children to be in the range of 0.01% to 3.3% globally. Some studies from Malaysia reported a strabismus prevalence of 1.4%-2.2% (Teoh and Yow, 1982; Goh et al., 2005), whereas, it was reported to be 0.8% in Singaporean Chinese children (Chia et al., 2010), 1.9%-3% in China (He et al., 2004), 1.28% in Japan (Matsuo and Matsuo, 2007), up to 3.3% in United States (Chew et al., 1994), 2.8% in Australia (Robaei et al., 2006), and 2.3% in United Kingdom (Williams et al., 2008).
Teoh and Yow (1982) conducted the study in Petaling Jaya, Malaysia, involving 650 school children aged 7. Fourteen (2.2%) of them were found to have strabismus, of which 86% were exotropia, 7% alternating esotropia and 7% hypertropia. Another population-based, cross-sectional survey was done by Goh et al. (2005) on 4634 children, aged 7 to 15 years, living in a suburban area near Kuala Lumpur city. They
21
reported strabismus in 1.4% of the children in which mostly (up to 85%) were exotropia.
Chia et al. (2010) carried out a door to door survey in the South-Western region of Singapore, recruiting 3009 children aged 6 to 72 months. They observed a lower prevalence of strabismus (0.8%) among young Singaporean Chinese children.
Majority of the strabismic children had intermittent exotropia (58%), followed by constant exotropia (25%) and constant esotropia (12%).
In Guangzhou, China, He et al. (2004) studied on 5053 children aged 5 to 15 years and reported prevalence of strabismus to be 1.9% to 3.0%. Most of them were exotropia (80% with near and 86% with distant fixation). Matsuo and Matsuo (2007) carried out a large-scale population-based survey in Okayama Prefecture, Japan.
Questionnaires were mailed to elementary schools and a total 86531 children, aged 6 to 12 years participated in the surgey. They observed 1.28% of the children were found to have strabismus where 0.69% were exotropia and 0.28% were esotropia.
In the United States, the Baltimore Paediatric Eye Disease Study examined 2546 white and African American children aged 6 through 71 months and revealed that 3.3% of white and 2.1% of African American children had manifest strabismus.
(Friedman et al., 2009). Robaei et al. (2006) reported a 2.8% prevalence of strabismus in a population-based cross-sectional study in Sydney. 1739 children aged 6 years was recruited and reported that 54% had esotropia and 29% had exotropia.
Whereas in the United Kingdom, Williams et al. (2008) reported a 2.3% prevalence of strabismus in 7825 seven year-old children. And it was also reported that 73.4% were esotropia, 21.4% were exotropia and 5.2% had a vertical component.
22
There are four types of strabismus. They are the horizontal strabismus: esotropia and exotropia; and the vertical strabismus: hypertropia and hypotropia. Esotropia is an inward turning of the eyes or also known as "crossed eyes". Exotropia is an outward deviation of the eyes forming a divergent angle of the eyes or also known as "wall eyes". Hypertropia is an upward deviation of the eyes whereas hypotropia is a downward turning of the eyes. Strabismus is equally common in boys and girls and sometimes runs in families.
The prevalence of the type of strabismus varies based on racial and ethnic background. Exotropia occurs more commonly in the Middle East, subequatorial Africa and the Asian populations than in the United States as quoted from Noorden (1996). Jenkins (1992) made the interesting observation that the nearer a country is to the equator the higher the prevalence of exodeviations. Whereas Europeans, Australians and Americans are predominantly diagnosed with esotropia. The basis of this difference may be in part linked with population-based differences in refractive error. Cotter et al. (2011) investigated the risk factors associated with esotropia or exotropia in a population-based cross-sectional prevalence study where 9970 children ages 6 to 72 months from California and Maryland participated. They reported that esotropia is commonly associated with hyperopia, whereas exotropia is more associated with myopia. Yu et al. (2002) also reported a higher prevalence of exotropia in Hong Kong as the population becomes less hyperopic.
Sometimes, the child cannot use both eyes together but has to fixate with one or the other. The eye that looks straight at a given time is the fixing eye. Visual acuity diminishes with diminished use of an eye, and suppression amblyopia may develop.
23
Early treatment usually improves vision and appearance. Generally, the most satisfactory results are achieved if the condition is corrected before the age of seven years old. However, if strabismus is left untreated, it may result in loss of binocularity and depth perception.
24 1.1.2 Functional effects of Strabismus
In strabismus, there is disruption of binocular vision which leads to images forming in non-corresponding points in both retinae. This causes overlapping of different foveal images from the fixating eye and the deviating eye. Noorden published an article in 1985, explaining that in order to minimize the disorganization and confusion, there is an active inhibition within the retino-cortical pathways of visual input which originates from the fovea of the deviating eye (Noorden, 1985). This mechanism prevents diplopia or confusion due to visual adaptation via anomalous retinal correspondence or known as visual suppression. This will result in poor vision in the non-fixating eye causing amblyopia.
Amblyopia is defined as unilateral or less commonly, bilateral reduced best corrected visual acuity (BCVA) in the absence of organic abnormality of the eye (Noorden, 1985). If left untreated or inadequately treated, it can cause permanent loss of vision.
Although amblyopia generally develops in children aged less than seven years, it can still happen at any age prior to visual maturation. But early accurate diagnosis and treatment of amblyopia should be carried out. Birch and Wang (2009) did a review on the normal maturation of stereoacuity, the stereoacuity deficits associated with infantile and accommodative esotropia and strategies for improving stereoacuity outcomes. They concluded early diagnosis and treatment may result in improved vision, leading to a better prognosis for binocular vision development, a more stable alignment for surgery if required and improved long term quality of life.
