Strabismus, 2013; 21(4): 203–208 ! Informa Healthcare USA, Inc. ISSN: 0927-3972 print / 1744-5132 online DOI: 10.3109/09273972.2013.833952
The Psychological Impact Of Strabismus: Does The Angle Really Matter? Ailsa Ritchie, Patricio Colapinto, and Saurabh Jain Royal Free Hospital, Ophthalmology, London, UK
ABSTRACT Introduction: The psychological impact of strabismus is well recognized. Patients with strabismus have lower levels of psychological well being compared to normal controls. Few studies have evaluated the relationship between levels of psychological distress and the angle of deviation, age, sex, presence of diplopia, visual acuity and direction of deviation. Methods: 50 patients with strabismus who attended the adult strabismus clinic were included in this questionnaire based prospective study. The Psychological Impact questionnaire was used to assess the psychological impact of noticeable strabismus. We measured the angle of deviation, age, sex, presence of diplopia, visual acuity and direction of deviation and correlated these with psychological impact scores. Student’s t-test and Pearson’s correlation coefficient (r) were used in statistical analysis. Results: The average age was 48 years (range 15-84) and there were 26 females and 24 males. There was no correlation between psychological impact score and the maximum degree of horizontal deviation r = 0.02 (95% CI 0.26 to 0.29), p = 0.9, the maximum angle of vertical deviation r = 0.26 (95% CI 0.01 to 0.51), p = 0.06, age r = 0.09 (95% CI 0.36 to 0.19), p = 0.5, sex (p = 0.96), presence of diplopia (p = 0.6), visual acuity of the worse eye r = 0.01 (95% CI 0.29 to 0.27), p = 0.9 and direction of deviation (p = 0.8 for eso-deviations compared to exodeviations, p = 0.4 for horizontal compared to vertical deviations). There was a slight negative correlation between psychological impact score and visual acuity of the better eye r = 0.28 (95% CI 0.52 to 0.01), p = 0.04. Conclusion: The psychological impact of strabismus does not appear to be related to the patient’s angle of deviation, age, sex, presence of diplopia, visual acuity or direction of deviation. Larger studies are required using strabismus specific tools for evaluating psychological impact to further investigate these findings. Keywords: Adult strabismus, quality of life, strabismus surgery incisional
INTRODUCTION
20 13
with strabismus are perceived to be less attractive, less interesting, less successful, and less intelligent than people without strabismus. Olitsky et al.4 and Coats et al.5 demonstrated that strabismus negatively impacts on ability to gain employment. The psychological impact of strabismus has been studied with general measures such as the Hospital Anxiety and Depression Scale (HADS), the Derriford Appearance Scale 59 (DAS59), a shortened version of the World Health Organization Quality of Life assessment instrument (WHO QoL Bref), and the Hopkins Symptom Checklist,6,7,8 as well as questionnaires designed specifically for strabismus, including the
The social and psychological impact of strabismus has been widely described.1 The social impact of strabismus is present from an early age. Mojon-Azzi et al.2 digitally altered photographs of children to produce pairs of twins, one with and one without a squint. They asked 118 children to choose which twin they would invite to their birthday party. Photographs of the child with a squint were selected statistically less often than the same photograph without a squint by children over the age of 6 years. Social stigma persists into adulthood. Mojon-Azzi et al.3 found that people
Received 17 October 2012; Revised 9 July 2013; Accepted 5 August 2013; Published online 25 October 2013 Correspondence: Saurabh Jain, Royal Free Hospital, Ophthalmology, Pond Street, London, NW3 2QG, United Kingdom. Email: [email protected]
203
204 A. Ritchie et al. Amblyopia and Strabismus Questionnaire (A&SQ),9 the Psychological Impact questionnaire10 and the Adult Strabismus 20 (AS-20)11,22. Studies have consistently shown that people with strabismus have problems with self-image and higher rates of generalized anxiety or distress compared with normal controls.6,7,8 Few studies have evaluated whether there is a relationship between size of deviation and psychological impact. Nelson et al.12 found that people with over 25 prism diopters (PD) of strabismus reported more frequently that strabismus had a negative impact on their self-esteem than patients who had less than 25 PD of strabismus. Van de Graaf et al.13 used the A&SQ to evaluate the functional and psychological impact of amblyopia and strabismus on 137 patients who were re-examined 30–35 years after occlusion therapy. They found no correlation between the angle size of strabismus and any of the 5 domains in the questionnaire (fear of losing the better eye; distance estimation; visual disorientation; diplopia; social contact and cosmetic problems). Jackson et al. gave questionnaires to 46 patients before and after surgical correction of their strabismus and found a correlation between degree of horizontal deviation and HADS scores, the psychological and environmental domain scores of the WHO QoL BREF, and the strabismus noticeability subset scores of the visual analog scale (VAS) preoperatively, but these were not significant postoperatively. Multiple regression analysis by Jackson et al.7 suggested some effect of sex, diplopia, and direction of misalignment, but they acknowledged that further study was needed. Sabri et al.10 designed a Psychological Impact questionnaire to assess the psychological impact of amblyopia, strabismus, wearing glasses, and previous patching experience. All components of the questionnaire had high levels of agreement and reproducibility on cases with amblyopia with or without strabismus and controls. Patients with noticeable strabismus had higher psychological impact scores indicating worse psychological wellbeing than patients without noticeable strabismus. However, these cases also had more severe amblyopia and an unpleasant patching experience, which may have been a factor. We designed a questionnaire-based prospective study using the Psychological Impact questionnaire10 to investigate whether the size of the angle of deviation, age, sex, presence of diplopia, visual acuity of the worse eye, and direction of deviation are related to psychological impact.
Free Hospital, London, United Kingdom, and informed consent was obtained. All patients considered their strabismus to be noticeable and were keen for intervention. All patients were assessed by an experienced orthoptist, who measured best corrected visual acuity in each eye using a Snellen chart at 6 m. Snellen visual acuity measurements were converted to logMAR units for analysis. An alternating prism cover test during fixation at 1/3 m for near and at a distance target was performed to measure angles of horizontal and vertical deviation in prism diopters. The largest angles of horizontal and vertical deviation, be that at near or distance, measured at the time of questionnaire completion, were recorded along with the direction of deviation. All patients underwent an ophthalmic examination and the cause of their strabismus was recorded. Patients were asked if they experienced any double vision and the presence or absence of diplopia was recorded. Participants were asked to fill out the Psychological Impact questionnaire. Each questionnaire item is applied in 4 different contexts, including general daily life, having a weaker eye, wearing glasses, and having noticeable strabismus, as shown in Figure 1. We asked patients to complete this questionnaire in the context of having noticeable strabismus only. To calculate the psychological impact score we took the average score and multiplied it by 25 to get a score ranging from 0 (no detrimental psychological impact) and 100 (severe detrimental psychological impact) as described by Sabri et al.10 We correlated the score against the largest angle of horizontal and vertical deviation, age, sex, presence of diplopia, visual acuity of the worse eye, and direction of deviation. Pearson’s correlation coefficient and Student’s t-test were used in the statistical analysis, which was performed using Microsoft Office Excel 2007. Ethical approval was obtained from the local institutional review board and the study was compliant with the Declaration of Helsinki.
RESULTS Fifty patients participated in the study, including 26 females and 24 males. The average age was 48 years (range 15 to 84 years, standard deviation [SD] = 20.7). The mean psychological impact score was 23 (SD = 14.3). The causes of strabismus are listed in Table 1.
Largest Angle of Horizontal Deviation MATERIALS AND METHODS Patients with strabismus were recruited between 2009 and 2010 from the adult strabismus clinic at the Royal
The average horizontal deviation was 33 PD (SD = 19.8 PD). Only 2 patients had a purely vertical deviation. There was no correlation between the maximum degree of horizontal strabismus and psychological Strabismus
The psychological impact of strabismus
205
FIGURE 1. The Psychological Impact questionnaire, designed and validated by Sabri et al10. TABLE 1. Patient diagnoses. Diagnosis Intermittent or decompensated esotropia Intermittent or decompensated esotropia with A or V pattern Intermittent or decompensated exotropia Intermittent or decompensated exotropia with A or V pattern Consecutive exotropia Post vitrectomy strabismus Dissociated vertical deviation Monocular elevation deficit syndrome 3rd nerve palsy 4th nerve palsy 6th nerve palsy Vitreous haemorrhage Anterior ischaemic optic neuropathy Trauma Multiple sclerosis Myasthenia gravis Uncertain diagnosis
Number of patients 9 1 14 3 8 1 1 1 1 2 2 1 1 1 1 1 2
FIGURE 3. A scatterplot to show the relationship between maximum angle of vertical deviation and psychological impact score.
impact score, as shown in Figure 2. Pearson’s correlation co-efficient was 0.02 (95% confidence interval [CI]: 0.26 to 0.29, p = 0.9).
Largest Angle of Vertical Deviation The mean vertical angle of deviation was 6 PD (SD = 7.6). Pearson’s correlation co-efficient was 0.26 (95% CI: 0.01 to 0.51, p = 0.06). There was no correlation between the maximum angle of vertical strabismus and psychological impact score, as shown in Figure 3. When patients with a purely horizontal deviation were excluded, the mean vertical deviation was 12.6 PD (SD = 6.1) and the mean psychological impact score was 25. Pearson’s correlation co-efficient was 0.35 (95% CI: 0.05 to 0.66, p = 0.08).
Age FIGURE 2. A scatterplot to show the relationship between maximum angle of horizontal deviation and psychological impact score. !
2013 Informa Healthcare USA, Inc.
There was no correlation between age and psychological impact score, with a Pearson’s correlation coefficient of 0.09 (95% CI: 0.36 to 0.19, p = 0.5).
206 A. Ritchie et al.
Sex Student’s t-test indicates that there is no difference between the psychological impact scores of male and female patients (p = 0.96). Female patients had a mean psychological impact score of 23 (95% CI: 17 to 28) and male patients had a mean psychological impact score of 23 (95% CI: 17 to 28).
Diplopia Twenty-three patients complained of associated diplopia, while 27 did not. Student’s t-test indicates that there is no difference in the psychological impact scores in patients with and without diplopia (p = 0.6). Patients with diplopia had a mean psychological impact score of 21 (95% CI: 14 to 28) and patients without diplopia had a mean psychological impact score of 24 (95% CI: 19 to 28).
Visual Acuity of the Better Eye The mean visual acuity of the better eye was 6/6 (0.03 logMAR) (range 6/4( 0.2 logMAR) to 6/12 (0.3 logMAR)). There was a slight negative correlation between visual acuity of the better eye and psychological impact score, with a Pearson’s correlation coefficient of 0.28 (95% CI: 0.52 to 0.01, p = 0.04).
Visual Acuity of the Worse Eye The mean visual acuity of the worse eye was 6/12 (0.33 logMAR) (range 6/5 ( 0.1 logMAR) to counting fingers (2.0 logMAR)). There was no correlation between visual acuity of the worse eye and psychological impact score with a Pearson’s correlation coefficient of 0.01 (95% CI: 0.29 to 0.27, p = 0.9).
Direction of Deviation Fourteen patients had an eso-deviation, 6 with a vertical component. Thirty-three patients had an exodeviation, 16 with a vertical component. Two patients had a purely vertical deviation. In one patient the direction of deviation was not recorded and this patient was excluded from analysis. The mean psychological impact score in patients with an esodeviation with or without a vertical component was 21 (95% CI: 11 to 30) and in patients with an exodeviation with or without a vertical component was 22 (95% CI: 18 to 26). The Student’s t-test indicates that there is no difference between the psychological impact scores in patients with eso-deviations and those with exo-deviations (p = 0.8). Twenty-four
patients had a vertical component to their deviation with a mean psychological impact score of 24 (95% CI: 18 to 30) and 25 patients had a purely horizontal deviation with a mean psychological impact score of 21 (95% CI: 15 to 26). The Student’s t-test indicates that there is no difference between the psychological impact scores in patients with horizontal and vertical deviations (p = 0.4).
DISCUSSION Strabismus negatively impacts on psychological wellbeing. Our results indicate that the degree to which patients are affected is not related to their angle or direction of deviation, age, sex, presence of diplopia, or visual acuity of the worse eye. We found a slight negative correlation between psychological impact score and visual acuity of the better eye, but not the worse eye, which is difficult to explain and may be a spurious result due to the small sample size. The Psychological Impact questionnaire that we used was designed by and for a younger population of 16- to 18-year-old amblyopes with and without strabismus.10 The last two questions are concerned with visual function and are not directly relevant to patients in our study with strabismus but without reduced vision. Other questionnaires have been designed to assess the psychological well-being of patients with strabismus, including the A&SQ9,22 and the AS-20.11 In the A&SQ only 4 out of 26 questions related to psychological factors.9 Vianya-Estopa et al.14 suggested using separate questionnaires for amblyopia and strabismus, as some of the questions were not relevant to patients without strabismus. Half the questions in the AS-20 questionnaire relate to function, but there are 10 questions relating to psychological impact, and the questionnaire is specific for adult strabismus and has been found to be reproducible.15,16,23 It has been suggested that size of deviation may impact on the degree of psychological distress.11 Jackson et al. found a correlation between degree of horizontal deviation and HADS scores, the psychological and environmental domain scores of the WHO QoL BREF assessment instrument, and the strabismus noticeability subset scores of the VAS preoperatively, but these were not significant postoperatively. Sabri et al. (2004) observed that cases who considered themselves to have noticeable strabismus (n = 19) had significantly higher psychological impact scores than other cases and controls. In this study, out of 120 cases with amblyopia, 55 had no strabismus, 47 had manifest strabismus less than 10 PD, and 18 had over 10 PD of manifest strabismus. In our study, the angles of deviation were higher, with a mean horizontal deviation of 33 PD. A difference between very small angles of deviation and Strabismus
The psychological impact of strabismus psychological impact scores may not have been detected by our study, which also had less statistical power than the study by Sabri et al.10 Weissberg et al.17 showed digitally altered photographs simulating strabismus to 58 non–healthcare professionals. They found that as the angle of deviation increases, the proportion of observers noticing the strabismus also increases. Seventy percent of observers correctly identified the presence of strabismus at 14.5 PD of esotropia and 8 PD of exotropia. Ninety-seven percent and 95% of observers noticed a deviation of 24 PD of esotropia and exotropia, respectively. There could be a difference in the psychological impact of strabismus between patients with very small angles and around 24 PD of deviation, when strabismus is noticed by the majority of non–healthcare professionals. However, van de Graaf et al.13 found no correlation between angle size and ‘‘social contact and cosmetic problems’’ in a cohort of patients in which the most common strabismus diagnosis was microstrabismus. Sabri et al.10 found a significant difference between the psychological impact score of amblyopes with a visual acuity of 6/18 or worse and amblyopes with a better visual acuity. Van de Graaf et al.13 found that visual acuity in the worse eye at distance and near correlated with all 5 domains of the A&SQ. In this study all patients had amblyopia with a history of occlusion therapy. Sabri et al.10 suggested that the difference they observed could be explained by varying durations of patching time during childhood rather than differences in visual acuity alone. This may be the case as visual acuity in the worse eye was not related to psychological impact score in our study, in which not all patients had reduced visual acuity from amblyopia. However, our study had less statistical power to detect a difference. We found no significant difference between psychological impact scores across a wide range of ages within our sample (15 to 84 years of age). Burke et al.18 and Jackson et al.7 also found no correlation between participant age and degree of psychological impact. Jackson et al.10 found only a limited associated between sex and psychological impact on multivariant analysis. We found no correlation22. Hatt et al.11 used the AS-20 questionnaire to assess the psychological and functional impact of strabismus. They found that patients without diplopia had better levels of functioning but there was no difference in the psychosocial scores of patients with strabismus with and without diplopia. This is in keeping with our findings. In our study, we asked patients whether or not they had double vision but did not distinguish between patients who always had double vision and those who had it occasionally. There may have been a difference between these groups. Previous studies have reached different conclusions with regards to direction of deviation and psychological well-being. Mojon-Azzi et al.3 studied !
2013 Informa Healthcare USA, Inc.
207
the social impact of strabismus and found that people with exo-deviations were more negatively discriminated against than patients with eso-deviations. Burke et al.18 found that people with eso-deviations had better levels of psychological and social well-being both pre- and postoperatively. However, Olitsky et al.4 found that patients with eso-deviations had worse psychological well-being than patients with exo-deviations. We found no difference in psychological distress in patients with eso versus exo-deviations, which is in keeping with other studies.8,19 Patients in our study were recruited from the strabismus clinic and were actively seeking treatment. This introduces bias but the sample is representative of patients presenting for treatment. Preoperatively, it is unclear which factors affect the psychological wellbeing of patients with strabismus. Strabismus surgery and botulinum toxin injections have been shown to be highly cost-effective treatments for strabismus, improving psychological well-being and social functioning as well as binocularity and visual field gain.7,12,19–23 It appears that all patients can have a negative psychological impact from their strabismus, regardless of angle size, direction of deviation, age, sex, presence of diplopia, or visual acuity. These factors should therefore not impact on the decision to offer interventional treatments.
ACKNOWLEDGMENTS I would like to thank Safina Khan, Laura Gannon, and Komal Hirani for their orthoptic support.
DECLARATION OF INTEREST The authors declare no conflicts of interest.
REFERENCES 1. Durnian JM, Noonan CP, Marsh IB. The psychosocial effects of adult strabismus: a review. Br J Ophthalmol 2011; 95:450–453. 2. Mojon-Azzi SM, Kunz A, Mojon DS. Strabismus and discrimination in children: are children with strabismus invited to fewer birthday parties? Br J Ophthalmol 2011;95: 473–476. 3. Mojon-Azzi SM, Potnik W, Mojon DS. Opinions of dating agents about strabismic subjects’ ability to find a partner. Br J Ophthalmol 2008;92:765–769. 4. Olitsky SE, Sudesh S, Graziano A, et al. The negative psychosocial impact of strabismus in adults. J AAPOS 1999;3:209–211. 5. Coats DK, Paysse EA, Towler AJ, et al. Impact of large angle horizontal strabismus on ability to obtain employment. Ophthalmology 2000;107:402–405. 6. Durnian JM, Owen ME, Marsh IB. The psychosocial aspects of strabismus: correlation between the AS-20 and
208 A. Ritchie et al.
7.
8.
9.
10.
11.
12.
13.
14.
DAS59 quality-of-life questionnaires. J AAPOS 2009;13: 477–480. Jackson S, Harrad RA, Morris M, et al. The psychosocial benefits of corrective surgery for adults with strabismus. Br J Ophthalmol 2006;90:883–888. Satterfield D, Keltner JL, Morrison TL. Psychosocial aspects of strabismus study. Arch Ophthalmol 1993;111: 1100–1105. Van de Graaf ES, van der Sterre GW, Polling JR, et al. Amblyopia & Strabismus Questionnaire: design and initial validation. Strabismus 2004;12:181–193. Sabri K, Knapp CM, Thompson JR, et al. The VF-14 and psychological impact of amblyopia and strabismus. Invest Ophthalmol Vis Sci 2006;47:4386–4392. Hatt SR, Leske DA, Bradley EA, et al. Development of a quality-of-life questionnaire for adults with strabismus. Ophthalmology 2009;116:139–144. Nelson BA, Gunton KB, Lasker JN, et al. The psychosocial aspects of strabismus in teenagers and adults and the impact of surgical correction. J AAPOS 2008;12:72–76. Van de Graaf ES, van der Sterre GW, van Kempen H, et al. Amblyopia & Strabismus Questionnaire (A&SQ): clinical validation in a historic cohort. Graefes Arch Clin Exp Ophthalmol 2007;245:1589–1595. Vianya-Estopa M, Elliott DB, Barrett BT. An evaluation of the Amblyopia and Strabismus Questionnaire using rasch analysis. Invest Ophthalmol Vis Sci 2010;51:2496–2503.
15. Leske DA, Hatt SR, Holmes, JM. Test-retest reliability of health-related quality of life questionnaires in adults with strabismus. Am J Ophthalmol 2010;149:672–676. 16. Hatt SR, Leske DA, Bradley EA, et al. Comparison of quality of life instruments in adults with strabismus. Am J Ophthalmol 2009;148:558–562. 17. Weissberg E, Suckow M, Thorn F. Minimal angle horizontal strabismus detectable by lay observers. Optom Vis Sci 2004;81:505–509. 18. Burke JP, Leach CM, Davis H. Psychosocial implications of strabismus surgery in adults. J Pediatr Ophthalmol Strabismus 1997;34:159–164. 19. Menon V, Saha J, Tandon R, et al. Study of the psychosocial aspects of strabismus. J Pediatr Ophthalmol Strabismus 2002; 39:203–208. 20. Baker JD. The value of adult strabismus correction to the patient. J AAPOS 2002;6:136–140. 21. Beauchamp GR, Black BC, Coats DK, et al. The management of strabismus in adults - III. The effects on disability. J AAPOS 2005;9:455–459. 22. Beauchamp CL, Beauchamp GR, Stager DR, et al. The cost utility of strabismus surgery in adults. J AAPOS 2006;10: 394–399. 23. Fawcett SL, Felius J, Stager DR. Predictive factors underlying the restoration of macular binocular vision in adults with acquired strabismus. J AAPOS 2004;8: 439–444.
Strabismus
The Psychological Impact Of Strabismus: Does The Angle Really Matter? Ailsa Ritchie, Patricio Colapinto, and Saurabh Jain Royal Free Hospital, Ophthalmology, London, UK
ABSTRACT Introduction: The psychological impact of strabismus is well recognized. Patients with strabismus have lower levels of psychological well being compared to normal controls. Few studies have evaluated the relationship between levels of psychological distress and the angle of deviation, age, sex, presence of diplopia, visual acuity and direction of deviation. Methods: 50 patients with strabismus who attended the adult strabismus clinic were included in this questionnaire based prospective study. The Psychological Impact questionnaire was used to assess the psychological impact of noticeable strabismus. We measured the angle of deviation, age, sex, presence of diplopia, visual acuity and direction of deviation and correlated these with psychological impact scores. Student’s t-test and Pearson’s correlation coefficient (r) were used in statistical analysis. Results: The average age was 48 years (range 15-84) and there were 26 females and 24 males. There was no correlation between psychological impact score and the maximum degree of horizontal deviation r = 0.02 (95% CI 0.26 to 0.29), p = 0.9, the maximum angle of vertical deviation r = 0.26 (95% CI 0.01 to 0.51), p = 0.06, age r = 0.09 (95% CI 0.36 to 0.19), p = 0.5, sex (p = 0.96), presence of diplopia (p = 0.6), visual acuity of the worse eye r = 0.01 (95% CI 0.29 to 0.27), p = 0.9 and direction of deviation (p = 0.8 for eso-deviations compared to exodeviations, p = 0.4 for horizontal compared to vertical deviations). There was a slight negative correlation between psychological impact score and visual acuity of the better eye r = 0.28 (95% CI 0.52 to 0.01), p = 0.04. Conclusion: The psychological impact of strabismus does not appear to be related to the patient’s angle of deviation, age, sex, presence of diplopia, visual acuity or direction of deviation. Larger studies are required using strabismus specific tools for evaluating psychological impact to further investigate these findings. Keywords: Adult strabismus, quality of life, strabismus surgery incisional
INTRODUCTION
20 13
with strabismus are perceived to be less attractive, less interesting, less successful, and less intelligent than people without strabismus. Olitsky et al.4 and Coats et al.5 demonstrated that strabismus negatively impacts on ability to gain employment. The psychological impact of strabismus has been studied with general measures such as the Hospital Anxiety and Depression Scale (HADS), the Derriford Appearance Scale 59 (DAS59), a shortened version of the World Health Organization Quality of Life assessment instrument (WHO QoL Bref), and the Hopkins Symptom Checklist,6,7,8 as well as questionnaires designed specifically for strabismus, including the
The social and psychological impact of strabismus has been widely described.1 The social impact of strabismus is present from an early age. Mojon-Azzi et al.2 digitally altered photographs of children to produce pairs of twins, one with and one without a squint. They asked 118 children to choose which twin they would invite to their birthday party. Photographs of the child with a squint were selected statistically less often than the same photograph without a squint by children over the age of 6 years. Social stigma persists into adulthood. Mojon-Azzi et al.3 found that people
Received 17 October 2012; Revised 9 July 2013; Accepted 5 August 2013; Published online 25 October 2013 Correspondence: Saurabh Jain, Royal Free Hospital, Ophthalmology, Pond Street, London, NW3 2QG, United Kingdom. Email: [email protected]
203
204 A. Ritchie et al. Amblyopia and Strabismus Questionnaire (A&SQ),9 the Psychological Impact questionnaire10 and the Adult Strabismus 20 (AS-20)11,22. Studies have consistently shown that people with strabismus have problems with self-image and higher rates of generalized anxiety or distress compared with normal controls.6,7,8 Few studies have evaluated whether there is a relationship between size of deviation and psychological impact. Nelson et al.12 found that people with over 25 prism diopters (PD) of strabismus reported more frequently that strabismus had a negative impact on their self-esteem than patients who had less than 25 PD of strabismus. Van de Graaf et al.13 used the A&SQ to evaluate the functional and psychological impact of amblyopia and strabismus on 137 patients who were re-examined 30–35 years after occlusion therapy. They found no correlation between the angle size of strabismus and any of the 5 domains in the questionnaire (fear of losing the better eye; distance estimation; visual disorientation; diplopia; social contact and cosmetic problems). Jackson et al. gave questionnaires to 46 patients before and after surgical correction of their strabismus and found a correlation between degree of horizontal deviation and HADS scores, the psychological and environmental domain scores of the WHO QoL BREF, and the strabismus noticeability subset scores of the visual analog scale (VAS) preoperatively, but these were not significant postoperatively. Multiple regression analysis by Jackson et al.7 suggested some effect of sex, diplopia, and direction of misalignment, but they acknowledged that further study was needed. Sabri et al.10 designed a Psychological Impact questionnaire to assess the psychological impact of amblyopia, strabismus, wearing glasses, and previous patching experience. All components of the questionnaire had high levels of agreement and reproducibility on cases with amblyopia with or without strabismus and controls. Patients with noticeable strabismus had higher psychological impact scores indicating worse psychological wellbeing than patients without noticeable strabismus. However, these cases also had more severe amblyopia and an unpleasant patching experience, which may have been a factor. We designed a questionnaire-based prospective study using the Psychological Impact questionnaire10 to investigate whether the size of the angle of deviation, age, sex, presence of diplopia, visual acuity of the worse eye, and direction of deviation are related to psychological impact.
Free Hospital, London, United Kingdom, and informed consent was obtained. All patients considered their strabismus to be noticeable and were keen for intervention. All patients were assessed by an experienced orthoptist, who measured best corrected visual acuity in each eye using a Snellen chart at 6 m. Snellen visual acuity measurements were converted to logMAR units for analysis. An alternating prism cover test during fixation at 1/3 m for near and at a distance target was performed to measure angles of horizontal and vertical deviation in prism diopters. The largest angles of horizontal and vertical deviation, be that at near or distance, measured at the time of questionnaire completion, were recorded along with the direction of deviation. All patients underwent an ophthalmic examination and the cause of their strabismus was recorded. Patients were asked if they experienced any double vision and the presence or absence of diplopia was recorded. Participants were asked to fill out the Psychological Impact questionnaire. Each questionnaire item is applied in 4 different contexts, including general daily life, having a weaker eye, wearing glasses, and having noticeable strabismus, as shown in Figure 1. We asked patients to complete this questionnaire in the context of having noticeable strabismus only. To calculate the psychological impact score we took the average score and multiplied it by 25 to get a score ranging from 0 (no detrimental psychological impact) and 100 (severe detrimental psychological impact) as described by Sabri et al.10 We correlated the score against the largest angle of horizontal and vertical deviation, age, sex, presence of diplopia, visual acuity of the worse eye, and direction of deviation. Pearson’s correlation coefficient and Student’s t-test were used in the statistical analysis, which was performed using Microsoft Office Excel 2007. Ethical approval was obtained from the local institutional review board and the study was compliant with the Declaration of Helsinki.
RESULTS Fifty patients participated in the study, including 26 females and 24 males. The average age was 48 years (range 15 to 84 years, standard deviation [SD] = 20.7). The mean psychological impact score was 23 (SD = 14.3). The causes of strabismus are listed in Table 1.
Largest Angle of Horizontal Deviation MATERIALS AND METHODS Patients with strabismus were recruited between 2009 and 2010 from the adult strabismus clinic at the Royal
The average horizontal deviation was 33 PD (SD = 19.8 PD). Only 2 patients had a purely vertical deviation. There was no correlation between the maximum degree of horizontal strabismus and psychological Strabismus
The psychological impact of strabismus
205
FIGURE 1. The Psychological Impact questionnaire, designed and validated by Sabri et al10. TABLE 1. Patient diagnoses. Diagnosis Intermittent or decompensated esotropia Intermittent or decompensated esotropia with A or V pattern Intermittent or decompensated exotropia Intermittent or decompensated exotropia with A or V pattern Consecutive exotropia Post vitrectomy strabismus Dissociated vertical deviation Monocular elevation deficit syndrome 3rd nerve palsy 4th nerve palsy 6th nerve palsy Vitreous haemorrhage Anterior ischaemic optic neuropathy Trauma Multiple sclerosis Myasthenia gravis Uncertain diagnosis
Number of patients 9 1 14 3 8 1 1 1 1 2 2 1 1 1 1 1 2
FIGURE 3. A scatterplot to show the relationship between maximum angle of vertical deviation and psychological impact score.
impact score, as shown in Figure 2. Pearson’s correlation co-efficient was 0.02 (95% confidence interval [CI]: 0.26 to 0.29, p = 0.9).
Largest Angle of Vertical Deviation The mean vertical angle of deviation was 6 PD (SD = 7.6). Pearson’s correlation co-efficient was 0.26 (95% CI: 0.01 to 0.51, p = 0.06). There was no correlation between the maximum angle of vertical strabismus and psychological impact score, as shown in Figure 3. When patients with a purely horizontal deviation were excluded, the mean vertical deviation was 12.6 PD (SD = 6.1) and the mean psychological impact score was 25. Pearson’s correlation co-efficient was 0.35 (95% CI: 0.05 to 0.66, p = 0.08).
Age FIGURE 2. A scatterplot to show the relationship between maximum angle of horizontal deviation and psychological impact score. !
2013 Informa Healthcare USA, Inc.
There was no correlation between age and psychological impact score, with a Pearson’s correlation coefficient of 0.09 (95% CI: 0.36 to 0.19, p = 0.5).
206 A. Ritchie et al.
Sex Student’s t-test indicates that there is no difference between the psychological impact scores of male and female patients (p = 0.96). Female patients had a mean psychological impact score of 23 (95% CI: 17 to 28) and male patients had a mean psychological impact score of 23 (95% CI: 17 to 28).
Diplopia Twenty-three patients complained of associated diplopia, while 27 did not. Student’s t-test indicates that there is no difference in the psychological impact scores in patients with and without diplopia (p = 0.6). Patients with diplopia had a mean psychological impact score of 21 (95% CI: 14 to 28) and patients without diplopia had a mean psychological impact score of 24 (95% CI: 19 to 28).
Visual Acuity of the Better Eye The mean visual acuity of the better eye was 6/6 (0.03 logMAR) (range 6/4( 0.2 logMAR) to 6/12 (0.3 logMAR)). There was a slight negative correlation between visual acuity of the better eye and psychological impact score, with a Pearson’s correlation coefficient of 0.28 (95% CI: 0.52 to 0.01, p = 0.04).
Visual Acuity of the Worse Eye The mean visual acuity of the worse eye was 6/12 (0.33 logMAR) (range 6/5 ( 0.1 logMAR) to counting fingers (2.0 logMAR)). There was no correlation between visual acuity of the worse eye and psychological impact score with a Pearson’s correlation coefficient of 0.01 (95% CI: 0.29 to 0.27, p = 0.9).
Direction of Deviation Fourteen patients had an eso-deviation, 6 with a vertical component. Thirty-three patients had an exodeviation, 16 with a vertical component. Two patients had a purely vertical deviation. In one patient the direction of deviation was not recorded and this patient was excluded from analysis. The mean psychological impact score in patients with an esodeviation with or without a vertical component was 21 (95% CI: 11 to 30) and in patients with an exodeviation with or without a vertical component was 22 (95% CI: 18 to 26). The Student’s t-test indicates that there is no difference between the psychological impact scores in patients with eso-deviations and those with exo-deviations (p = 0.8). Twenty-four
patients had a vertical component to their deviation with a mean psychological impact score of 24 (95% CI: 18 to 30) and 25 patients had a purely horizontal deviation with a mean psychological impact score of 21 (95% CI: 15 to 26). The Student’s t-test indicates that there is no difference between the psychological impact scores in patients with horizontal and vertical deviations (p = 0.4).
DISCUSSION Strabismus negatively impacts on psychological wellbeing. Our results indicate that the degree to which patients are affected is not related to their angle or direction of deviation, age, sex, presence of diplopia, or visual acuity of the worse eye. We found a slight negative correlation between psychological impact score and visual acuity of the better eye, but not the worse eye, which is difficult to explain and may be a spurious result due to the small sample size. The Psychological Impact questionnaire that we used was designed by and for a younger population of 16- to 18-year-old amblyopes with and without strabismus.10 The last two questions are concerned with visual function and are not directly relevant to patients in our study with strabismus but without reduced vision. Other questionnaires have been designed to assess the psychological well-being of patients with strabismus, including the A&SQ9,22 and the AS-20.11 In the A&SQ only 4 out of 26 questions related to psychological factors.9 Vianya-Estopa et al.14 suggested using separate questionnaires for amblyopia and strabismus, as some of the questions were not relevant to patients without strabismus. Half the questions in the AS-20 questionnaire relate to function, but there are 10 questions relating to psychological impact, and the questionnaire is specific for adult strabismus and has been found to be reproducible.15,16,23 It has been suggested that size of deviation may impact on the degree of psychological distress.11 Jackson et al. found a correlation between degree of horizontal deviation and HADS scores, the psychological and environmental domain scores of the WHO QoL BREF assessment instrument, and the strabismus noticeability subset scores of the VAS preoperatively, but these were not significant postoperatively. Sabri et al. (2004) observed that cases who considered themselves to have noticeable strabismus (n = 19) had significantly higher psychological impact scores than other cases and controls. In this study, out of 120 cases with amblyopia, 55 had no strabismus, 47 had manifest strabismus less than 10 PD, and 18 had over 10 PD of manifest strabismus. In our study, the angles of deviation were higher, with a mean horizontal deviation of 33 PD. A difference between very small angles of deviation and Strabismus
The psychological impact of strabismus psychological impact scores may not have been detected by our study, which also had less statistical power than the study by Sabri et al.10 Weissberg et al.17 showed digitally altered photographs simulating strabismus to 58 non–healthcare professionals. They found that as the angle of deviation increases, the proportion of observers noticing the strabismus also increases. Seventy percent of observers correctly identified the presence of strabismus at 14.5 PD of esotropia and 8 PD of exotropia. Ninety-seven percent and 95% of observers noticed a deviation of 24 PD of esotropia and exotropia, respectively. There could be a difference in the psychological impact of strabismus between patients with very small angles and around 24 PD of deviation, when strabismus is noticed by the majority of non–healthcare professionals. However, van de Graaf et al.13 found no correlation between angle size and ‘‘social contact and cosmetic problems’’ in a cohort of patients in which the most common strabismus diagnosis was microstrabismus. Sabri et al.10 found a significant difference between the psychological impact score of amblyopes with a visual acuity of 6/18 or worse and amblyopes with a better visual acuity. Van de Graaf et al.13 found that visual acuity in the worse eye at distance and near correlated with all 5 domains of the A&SQ. In this study all patients had amblyopia with a history of occlusion therapy. Sabri et al.10 suggested that the difference they observed could be explained by varying durations of patching time during childhood rather than differences in visual acuity alone. This may be the case as visual acuity in the worse eye was not related to psychological impact score in our study, in which not all patients had reduced visual acuity from amblyopia. However, our study had less statistical power to detect a difference. We found no significant difference between psychological impact scores across a wide range of ages within our sample (15 to 84 years of age). Burke et al.18 and Jackson et al.7 also found no correlation between participant age and degree of psychological impact. Jackson et al.10 found only a limited associated between sex and psychological impact on multivariant analysis. We found no correlation22. Hatt et al.11 used the AS-20 questionnaire to assess the psychological and functional impact of strabismus. They found that patients without diplopia had better levels of functioning but there was no difference in the psychosocial scores of patients with strabismus with and without diplopia. This is in keeping with our findings. In our study, we asked patients whether or not they had double vision but did not distinguish between patients who always had double vision and those who had it occasionally. There may have been a difference between these groups. Previous studies have reached different conclusions with regards to direction of deviation and psychological well-being. Mojon-Azzi et al.3 studied !
2013 Informa Healthcare USA, Inc.
207
the social impact of strabismus and found that people with exo-deviations were more negatively discriminated against than patients with eso-deviations. Burke et al.18 found that people with eso-deviations had better levels of psychological and social well-being both pre- and postoperatively. However, Olitsky et al.4 found that patients with eso-deviations had worse psychological well-being than patients with exo-deviations. We found no difference in psychological distress in patients with eso versus exo-deviations, which is in keeping with other studies.8,19 Patients in our study were recruited from the strabismus clinic and were actively seeking treatment. This introduces bias but the sample is representative of patients presenting for treatment. Preoperatively, it is unclear which factors affect the psychological wellbeing of patients with strabismus. Strabismus surgery and botulinum toxin injections have been shown to be highly cost-effective treatments for strabismus, improving psychological well-being and social functioning as well as binocularity and visual field gain.7,12,19–23 It appears that all patients can have a negative psychological impact from their strabismus, regardless of angle size, direction of deviation, age, sex, presence of diplopia, or visual acuity. These factors should therefore not impact on the decision to offer interventional treatments.
ACKNOWLEDGMENTS I would like to thank Safina Khan, Laura Gannon, and Komal Hirani for their orthoptic support.
DECLARATION OF INTEREST The authors declare no conflicts of interest.
REFERENCES 1. Durnian JM, Noonan CP, Marsh IB. The psychosocial effects of adult strabismus: a review. Br J Ophthalmol 2011; 95:450–453. 2. Mojon-Azzi SM, Kunz A, Mojon DS. Strabismus and discrimination in children: are children with strabismus invited to fewer birthday parties? Br J Ophthalmol 2011;95: 473–476. 3. Mojon-Azzi SM, Potnik W, Mojon DS. Opinions of dating agents about strabismic subjects’ ability to find a partner. Br J Ophthalmol 2008;92:765–769. 4. Olitsky SE, Sudesh S, Graziano A, et al. The negative psychosocial impact of strabismus in adults. J AAPOS 1999;3:209–211. 5. Coats DK, Paysse EA, Towler AJ, et al. Impact of large angle horizontal strabismus on ability to obtain employment. Ophthalmology 2000;107:402–405. 6. Durnian JM, Owen ME, Marsh IB. The psychosocial aspects of strabismus: correlation between the AS-20 and
208 A. Ritchie et al.
7.
8.
9.
10.
11.
12.
13.
14.
DAS59 quality-of-life questionnaires. J AAPOS 2009;13: 477–480. Jackson S, Harrad RA, Morris M, et al. The psychosocial benefits of corrective surgery for adults with strabismus. Br J Ophthalmol 2006;90:883–888. Satterfield D, Keltner JL, Morrison TL. Psychosocial aspects of strabismus study. Arch Ophthalmol 1993;111: 1100–1105. Van de Graaf ES, van der Sterre GW, Polling JR, et al. Amblyopia & Strabismus Questionnaire: design and initial validation. Strabismus 2004;12:181–193. Sabri K, Knapp CM, Thompson JR, et al. The VF-14 and psychological impact of amblyopia and strabismus. Invest Ophthalmol Vis Sci 2006;47:4386–4392. Hatt SR, Leske DA, Bradley EA, et al. Development of a quality-of-life questionnaire for adults with strabismus. Ophthalmology 2009;116:139–144. Nelson BA, Gunton KB, Lasker JN, et al. The psychosocial aspects of strabismus in teenagers and adults and the impact of surgical correction. J AAPOS 2008;12:72–76. Van de Graaf ES, van der Sterre GW, van Kempen H, et al. Amblyopia & Strabismus Questionnaire (A&SQ): clinical validation in a historic cohort. Graefes Arch Clin Exp Ophthalmol 2007;245:1589–1595. Vianya-Estopa M, Elliott DB, Barrett BT. An evaluation of the Amblyopia and Strabismus Questionnaire using rasch analysis. Invest Ophthalmol Vis Sci 2010;51:2496–2503.
15. Leske DA, Hatt SR, Holmes, JM. Test-retest reliability of health-related quality of life questionnaires in adults with strabismus. Am J Ophthalmol 2010;149:672–676. 16. Hatt SR, Leske DA, Bradley EA, et al. Comparison of quality of life instruments in adults with strabismus. Am J Ophthalmol 2009;148:558–562. 17. Weissberg E, Suckow M, Thorn F. Minimal angle horizontal strabismus detectable by lay observers. Optom Vis Sci 2004;81:505–509. 18. Burke JP, Leach CM, Davis H. Psychosocial implications of strabismus surgery in adults. J Pediatr Ophthalmol Strabismus 1997;34:159–164. 19. Menon V, Saha J, Tandon R, et al. Study of the psychosocial aspects of strabismus. J Pediatr Ophthalmol Strabismus 2002; 39:203–208. 20. Baker JD. The value of adult strabismus correction to the patient. J AAPOS 2002;6:136–140. 21. Beauchamp GR, Black BC, Coats DK, et al. The management of strabismus in adults - III. The effects on disability. J AAPOS 2005;9:455–459. 22. Beauchamp CL, Beauchamp GR, Stager DR, et al. The cost utility of strabismus surgery in adults. J AAPOS 2006;10: 394–399. 23. Fawcett SL, Felius J, Stager DR. Predictive factors underlying the restoration of macular binocular vision in adults with acquired strabismus. J AAPOS 2004;8: 439–444.
Strabismus
