Common forms of childhood strabismus in an incidence cohort

PURPOSE: To report the prevalent forms of childhood strabismus. DESIGN: Retrospective, population-based cohort study. METHODS: The medical records of all Olmsted County, Minnesota, residents younger than 19 years diagnosed with esotropia, exotropia, or hypertropia from January 1, 1985 through December 31, 1994, were reviewed. RESULTS: Six hundred twenty-seven new cases of childhood strabismus were identified during the 10-year study period, including 380 (60.1%) with esotropia, 205 (32.7%) with exotropia, and 42 (6.7%) with hypertropia. The five most common forms of strabismus included accommodative esotropia (27.9%), intermittent exotropia (16.9%), acquired nonaccommodative esotropia (10.2%), esotropia in children with an abnormal central nervous system (7.0%), and convergence insufficiency (6.4%). CONCLUSIONS: This study provides population-based data on the most prevalent forms of childhood strabismus. Accommodative esotropia, intermittent exotropia, and acquired nonaccommodative esotropia were the predominant forms of strabismus in this Western population.     

Botulinum toxin A in the treatment of concomitant strabismus in children

PURPOSE: To evaluate the results of treatment of esotropia, exotropia and hypertropia with botulinum toxin A. MATERIAL AND METHODS: 72 children with esotropia, exotropia and hypertropia treated with intramuscular injection of botulinum toxin A. RESULTS: Squint angle decreased 76% in children with alternant esotropia, 70% in children with monocular esotropia, 64% in alternant exotropia and 54% in monocular exotropia after treatment with botulinum toxin A. In hypertropia squint angle reduced in 50%. CONCLUSIONS: The use of injections of botulinum toxin A in treatment of concomitant strabismus improves position of eyes, which creates better conditions for development of localization with normal retinal correspondence.     

The perceived personality traits of adults with digitally induced large angle strabismus and the impact of its correction

Purpose:

To ascertain the effect of digitally induced large angle strabismus and its correction on social bias against strabismic adults.

Subjects and Methods:

This prospective, observational study included 10 orthotropic subjects whose face photographs were digitally altered to produce esotropia, exotropia, and hypertropia. Three batches of non-medical professionals, each consisting of 14 subjects, adjudged personality traits of the altered face photographs on a 10-item questionnaire. The same evaluators effected the appraisal of the orthotropic photographs. The personality score of the strabismic photograph of a subject was compared with its own orthotropic photograph.

Subjects and Methods:

This prospective, observational study included 10 orthotropic subjects whose face photographs were digitally altered to produce esotropia, exotropia, and hypertropia. Three batches of non-medical professionals, each consisting of 14 subjects, adjudged personality traits of the altered face photographs on a 10-item questionnaire. The same evaluators effected the appraisal of the orthotropic photographs. The personality score of the strabismic photograph of a subject was compared with its own orthotropic photograph.

Results:

The 10 subjects whose photographs were digitally modified were of the same age (21 years) and had equal gender distribution. The evaluation of the photographs was performed by 42 evaluators aged 38.3 ± 14.9 years, of whom 21 were males. Different personality traits were rated negatively in the strabismic photographs. The statistically significant negative impact was apparent on more number of personality traits for esotropia (7 out of 10) as compared to exotropia (4 out of 10) or hypertropia (3 out of 10). Rating of the strabismic photographs was significantly lower by female evaluators (P = 0.006). However, there was no difference whether the subject evaluating the photograph of the strabismic individual was of the same gender or the opposite gender. Internal consistency of the questionnaire was excellent (Cronbach''s Alpha = 0.81).

Conclusion:

There was a significant negative impact of strabismus on the perceived personality traits of the digitally altered face photographs of the adults when compared to their orthotropic photograph.     

The surgical results of correcting strabismus with inferior oblique hyperfunction

PURPOSE: To evaluate the surgical results of correcting strabismus with inferior oblique hyperfunction. MATERIAL AND METHODS: A retrospective chart review of 40 patients, who underwent surgery from 1999-2001 was performed. 7 patients had isolated inferior oblique hyperfunction, 5 with hypertropia, 23 patients had esotropia with inferior oblique hyperfunction and 5 patients had exotropia with inferior oblique hyperfunction. The recession of inferior oblique muscle was undergone in cases with inferior oblique hyperfunction, sometimes in hypertropia with anteposito. The recession-resection of rectus muscles with myotomy-tenotomy of inferior oblique muscle or his recession usually were performed in cases with coexisting esotropia or exotropia. RESULTS: In all cases eyes were acceptably aligned. The recession of inferior oblique muscle is the most effective method of operation in high oblique hyperfunction.     

Factors associated with a previous diagnosis of strabismus in a population-based sample of 12-year-old Australian children

PURPOSE: To describe the prevalence of strabismus and factors associated with its diagnosis in a representative sample of older Australian children. DESIGN: Cross-sectional, population-based study. METHODS: A representative stratified random cluster sample of 2353 children (aged 12 years) attending 21 secondary schools in Sydney, Australia was examined in 2004 to 2005 (response 75.3%). Cover testing was performed at near (30 cm) and distance (6 m); cycloplegic autorefraction, visual acuity, and stereoacuity were assessed. Previous strabismus diagnosis was obtained from parental questionnaires. RESULTS: Strabismus was evident in 64 children (2.7%); 21 (33%) had esotropia, 27 (42%) had exotropia, and 16 (25%) had microstrabismus. There were no gender (P = .2) or ethnicity (P = .6) associations. Previous diagnosis by an eye practitioner was noted in 27 (42%). This was related to hyperopia (P = .04), esotropia (P = .001), and amblyopia (P = .001). CONCLUSIONS: Strabismus was relatively infrequent in this Australian childhood sample. Its diagnosis was strongly related to presence of esotropia, hyperopia, and amblyopia.     

Epidemiology of Surgical Strabismus in Saudi Arabia

Purpose:?To describe the types and age differences of surgical strabismus.

Methods:?Records of 4,886 strabismus patients who underwent surgery at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia from 1982 to 1996 were analyzed. Demographic and clinical data were collected from all patients as a retrospective case series. The percentages and ratios of various types of strabismus were correlated with age and gender.

Results:?The average age of our patients was 13.2 years (range 4 months to 82 years). Esotropia was the most common type of strabismus (69.3%), while exotropia was less common (26.9%). Of patients undergoing esotropia correction, infantile esotropia and partially accommodative esotropia were equally common; non-accommodative was less common. Constant exotropia was almost three times more common than intermittent exotropia. The rate of sensory strabismus was high, 20.8% of all patients in the series, with a slight preponderance of sensory esotropia.

Conclusions:?The ratio of esotropia to exotropia in our study is comparable to previous studies done in predominantly European and Middle Eastern populations. Surgical esotropia decreased with age while surgical exotropia increased. Overall, our rates of sensory strabismus were much higher than previously reported, even if we compare only the younger patients.     

Refractive errors in children and young adults with Down’s syndrome

Purpose: Down’s syndrome (DS) is the most common chromosomal anomaly. Numerous ophthalmic features have been reported. The aim of our study was to investigate the incidence of refractive errors in children and young adults with DS in Macedonia. Methods: Fifty‐six children and young adults with DS, aged 2–28 years, from Macedonia, underwent slit‐lamp examination, ocular motility and refraction. Results: The overall incidence of refractive errors in the Macedonian children and young adults with DS was 96.4%. A total of 17.8% of the subjects had myopia, 23.2% had hypermetropia and 55.3% had astigmatism. Strabismus was seen in 13 (23.2%) of the subjects (nine had esotropia, three had exotropia, one had hypertropia). Conclusions: The incidence of refractive errors in Macedonian children and young adults with DS was similar to that in Asian children. Compared with White (Caucasian) and Asian children with DS, Macedonian children and young adults exhibited lower incidences of hypermetropia and myopia, and a higher incidence of astigmatism, in which oblique astigmatism represented the predominant type.     

同视机和三棱镜测量斜视角比较

目的：：探讨同视机和三棱镜测量斜视角的差异及其可能原因。方法：水平共同性斜视347例,其中内斜视76例,男37例,女39例,平均年龄13.27±7.77岁;外斜视271例,男131例,女140例,平均年龄15.43±8.42岁。分别以三棱镜加遮盖法(视远度数)和同视机进行斜视角测量。将数据输入SPSS 17.0软件行统计学处理。结果：外斜视的客观斜视角与三棱镜度的换算值：1°=0.29△~1.78△,值大小与是否为间歇性斜视有关( P=0.001)。内斜视客观斜视角与三棱镜度的换算值：1°=2.01△~2.15△。结论：外斜视客观斜视角与三棱镜度的差异表现为随斜视角的增加而增大;内斜视客观斜视角与三棱镜度的差异表现为随斜视角的增加而变小。同视机检查镜筒内+7.00D球镜的安装、患者近感性集合的影响及三棱镜块本身的缺陷可能是造成差异的主要原因。     

中国东北某医院2014─2017年间斜视住院患者斜视类型分布变化

目的：根据中国东北地区某医院眼科收集的数据,评估所有年龄阶段斜视住院患者的斜视类型和数量变化趋势。方法：回顾性分析2014年1月至2017年12月在哈尔滨医科大学附属第一医院眼科住院的斜视患者3 661例的资料。收集患者基本信息、斜视类型以及各种斜视的数量等信息,并观察分析斜视类型分布及斜视数量的变化趋势。组间数据比较采用方差分析、χ2 检验或Fisher确切概率法。 结果：最终纳入3 555例患者,年龄为1～79岁（15.5±11.6）岁,其中3 536例患者行斜视手术治疗。患者数量呈逐年递增趋势,且在每年1、2月份及7、8月份大致达到峰值（χ2 =956.67,P<0.001）。外斜视患者数量（71.8%）明显多于内斜视患者数量（16.0%）,差异有统计学意义（χ2 =31.41,P<0.001）, 其中间歇性外斜视是最常见的斜视类型。非调节性内斜视（77.6%）是所有内斜视中最常见的斜视类型。其他特殊类型斜视虽然患者数量较少,但依然有小幅度的上升趋势。在所有年龄阶段患者中, 12岁以下的患者最常见,占总数的56.0%,其中外斜视（71.5%）是最主要的斜视类型。结论：中国东北地区某医院2014─2017年外斜视患者比内斜视患者更常见,且外斜视患者的比例逐年增加,其中间歇性外斜视是最主要的斜视类型。此外12岁以下患者是最常见的患病人群。     

Prevalence of systemic and ocular disease in infantile exotropia: comparison with infantile esotropia.

OBJECTIVE: Exotropia in infancy is believed to be associated with an increased prevalence of neurologic, ocular, and craniofacial abnormalities; however, the prevalence of coexisting ocular and systemic disease in these patients is unknown. In this study, the prevalence of ocular disease and systemic illness was determined in patients diagnosed with exotropia in infancy. DESIGN: Observational comparative case series. PARTICIPANTS: Medical records of 70 patients diagnosed with exotropia in the first year of life were reviewed and compared with records of 136 patients diagnosed with esotropia before 1 year of age. INTERVENTION: Patients with no disorders (other than latent nystagmus, dissociated vertical deviation, or oblique muscle overaction) were grouped as "simple" strabismus. Patients with systemic disorders (including prematurity, neurologic disease, and genetic disease) and patients with ocular disorders (including congenital nystagmus, other strabismus, ptosis, and any condition associated with loss of vision [except amblyopia]) were grouped as "complex" strabismus. MAIN OUTCOME MEASURES: Prevalence of coexisting systemic and ocular disorders. The demographics, strabismus measurements, and types of coexisting disease in the simple and complex groups were compared. RESULTS: A high percentage of both exotropia (67%) and esotropia (49%) patients had a coexisting ocular or systemic abnormality. Exotropia patients with a constant strabismus were more likely to have coexisting ocular or systemic disease than those with an intermittent strabismus. Smaller angles of exotropia or esotropia were associated with a higher likelihood of coexisting ocular or systemic diseases. Systemic disorders were found more frequently than ocular disorders in both the exotropia and esotropia groups. In 25% of all patients referred for evaluation of strabismus, an additional ocular or systemic abnormality was discovered by the ophthalmologist. CONCLUSION: Patients presenting to a university hospital-based practice in the first year of life with exotropia were more likely than those presenting with esotropia to have coexisting ocular and systemic disease. Both groups had a notably high prevalence of associated disorders. The percentages measured in this population may not be applicable to other practices because of referral bias. However, clinicians should consider that children presenting with infantile exotropia and esotropia appear to be at risk for coexisting ocular or systemic disease.     

Results of combined divergence operation in intermittent exotropia in 120 children

BACKGROUND: Intermittent exotropia is the most frequent indication for surgical correction of exodeviations in childhood. Overcorrection with prolongated or persistent consecutive esotropia can impair binocular vision particularly in early childhood. We wanted to investigate this potential risk and the dose/effect relation of recess-resect surgery on children. PATIENTS AND METHODS: 120 children up to ten years of age underwent recess-resect surgery for intermittent exotropia in our clinic from 1991 to 1999 (< 2% of the surgical cases). The cycloplegic refraction was spectacle corrected with a reduction of 0.5 dpt. Preoperatively, a diagnostic occlusion was performed for three days. The amount of surgery was calculated using our dosage schedules based on effects one week postoperatively. The squint angles as measured by the alternate prism and cover test at 5 m and 0.3 m pre- and 3 months postoperatively and the binocular functions as measured by the Bagolini striated glasses, Titmus, Randot, TNO, or Lang tests were evaluated. RESULTS: (Medians) Squint angles in primary position were: preoperative: distance (5 m)--15 degrees, near (0.3 m)--16 degrees; postoperative (n = 104); distance--4 degrees, near--3 degrees. Effectivity of surgery: distance: 1.3 degrees/mm, near 1.4 degrees/mm. Consecutive esotropia requiring surgical correction occurred in 1 child. Second surgery for intermittent exotropia in the years 1991 to 1999 was necessary in 5 children. Binocular functions (n = 95): Preoperative = postoperative: 61%, postoperative > preoperative 21%, postoperative < preoperative 18%. The diagnostic occlusion was helpful to differentiate "pseudo-divergence excess type" from "divergence excess type" exotropia. The average deviation did not increase under the diagnostic occlusion. The effectivity of surgery (degree/mm) in the children group was lower than in a compared group of older patients (> 10 years) with intermittent exotropia. CONCLUSION: Using our own dosage schedules and surgical technique, residual exodeviations are common after recess-resect surgery in childhood. The risk of consecutive esotropia or persistent impairment of binocular vision is low.     

Changes in deviation following correction of hyperopia in children with fully refractive accommodative esotropia

Changes in deviation may occur following the correction of hyperopia in children with accommodative esotropia. We analyzed possible factors involving the development of changes in deviation. We examined 49 children (23 boys and 26 girls) who had fully refractive accommodative esotropia at the age of 3 or 4 years. All children wore glasses to correct the fully cycloplegic refractive errors. At the age of 10 or 11 years, 28 (57.1%) of these children had good alignment, 12 (24.5%) developed partial accommodative esotropia and 9 (18.4%) developed consecutive exotropia. The age at onset of esotropia, age at initial visit, and refraction, deviation and presence of stereopsis, as determined by the Titmus test using a fly at the initial visit, were similar among the three groups. In the consecutive exotropia group, amblyopia at the initial visit was significantly higher (89%) than that of the good alignment group (50%). The age at the start of the correction, and the refraction, amblyopia and presence of fusion (10 or 11 years) were almost equal among the three groups. We conclude that some children with fully refractive accommodative esotropia associated with amblyopia at the age of 3 or 4 years may be predisposed to developing consecutive exotropia.     

间歇性外斜视合并调节性内斜视：附8例报告

本文对我院3年2158例初诊斜视者中遇到的8例间歇性外斜视合并调节性内斜视进行分析讨论.归纳本型斜视病人的临床特征为:(1)发病年龄较早.(2)先发现内斜视.(3)患者常有中或高度远视(6/8).(4)AC/A 比率正常或偏低.(5)其斜视度变化大,外科30～15°(?)正位(?)内科15～30°.(6)内斜视可戴镜矫正.3例患者做了视觉电生理的眼球运动检查,但没获规律性的结果.最后讨论了本病的发病情况(0.4%,8/2158)和治疗问题.     

Full tendon transposition augmented with posterior intermuscular suture and recession--resection surgery

PURPOSE: To report an effect of the full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery, for the patient with monocular elevation deficiency (MED) and large exotropia. METHODS: Interventional case report. Full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery was performed for a 26-year-old male patient had monocular elevation deficiency (MED) and large exotropia. RESULTS: Preoperative angle of deviation was 56 prism diopters (PD) hypotropia and 45 PD right exotropia, compared with 18 PD left hypertropia and 10 PD right esotropia postoperatively. Essotropia persisted after 2.5 years, however, and so the right medial rectus was recessed after removal of the previous posterior intermuscular suture. At a three-year follow-up after the second surgery, alignment was straight in the primary position at near and far distances. CONCLUSIONS: Full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery was effective for a patient with MED associated with significant horizontal deviation, and a second operation was easily performed when overcorrection occurred.     

Global and regional prevalence of strabismus: a comprehensive systematic review and meta-analysis

ABSTRACT

Purpose: Despite the importance of information on the prevalence of strabismus, which can be effective in planning preventive and curative services, no study has addressed its prevalence comprehensively. In this study, a systematic search was done to estimate the regional and global prevalence of strabismus in different age and sex groups and factors affecting prevalence heterogeneity.

Methods: A comprehensive and systematic search was done in different international databases, including Web of Science, Scopus, PubMed, Embase, etc. to find published articles on the total prevalence of strabismus and the prevalence of exotropia and esotropia. A binomial distribution was used to calculate the prevalence and 95% confidence interval (CI). The Cochran’s Q-test and I² were applied to evaluate heterogeneity and a random-effects model was used to assess the pooled prevalence. The Begg’s test was administered to investigate publication bias and finally, a meta-regression method was applied to determine the factors affecting the heterogeneity among studies.

Results: Of 7980 articles, 56 articles with a total sample size of 229,396 were analyzed. Many of these articles (n = 14) were from the Regional Office for the Americas. The estimated of pooled prevalence (95% CI) of any strabismus, exotropia, and esotropia was 1.93% (1.64–2.21), 1.23% (1.00–1.46), and 0.77% (0.59–0.95), respectively. The heterogeneity in prevalence of strabismus and its subtypes according to I² was above 95% (p value <.001 for all). Age had a direct effect on heterogeneity in the prevalence of exotropia (b: 3.491; p: 0.002). Moreover, WHO region had a significant direct effect on heterogeneity in the prevalence of strabismus (b: 0.482; p < .001) and esotropia (b: 0.168; p: 0.027), and publication year had a significant direct effect on heterogeneity in the prevalence of exotropia (b: 0.059; p: 0.045). Sample size and publication year did not have any association with strabismus nor with other variables. There was no publication bias according to the Begg’s test.

Conclusion: The prevalence of strabismus varies widely in the world. As for factors affecting heterogeneity in the prevalence of strabismus, the results showed that age affected heterogeneity in the prevalence of exotropia, WHO region affected heterogeneity in the prevalence of strabismus and esotropia, and publication year affected heterogeneity in the prevalence of exotropia. Information about the global prevalence of strabismus can help health care planners design interventions and prioritize resource allocation.     

知觉性内/外斜视与视力障碍发病年龄关系的研究

目的 研究知觉性内斜视或外斜视的发生与视力障碍发病年龄的关系。方法 回顾性分析169例知觉性斜视的临床资料,包括视力障碍的发病年龄、病因和知觉性斜视的类型等。结果 169例知觉性斜视中34例先天性视力障碍(20％),其中20例(59％)发生知觉性内斜视,14例(41％)发生知觉性外斜视;135例(80％)获得性视力障碍,其中21例(16％)发生知觉性内斜视;114例(84％)发生知觉性外斜视。两组间有显著性差异,x~2=27.67,P<0.01。86例视力障碍(51％)因白内障所致,其中无晶状体者64例(74％)。结论 先天性视力障碍(发病年龄≤6个月)主要发生知觉性内斜视,获得性视力障碍(发病年龄>6个月)主要发生知觉性外斜视。白内障是导致知觉性斜视最常见的原因。     

连续性外斜视的病因及手术效果短期观察

目的 分析连续性外斜视的发生原因并探讨个性化设计的手术方式的术后效果。设计 回顾性病例系列。研究对象 北京同仁医院17例诊断为连续性外斜视并进行外斜视矫正术的患者。方法 对上述患者临床病历资料进行回顾,分析患者发现内斜视的年龄、屈光度、矫正视力、实施内斜视矫正术年龄、手术方式,以及发生连续性外斜视年龄、斜视角度、眼球运动、屈光度、双眼视觉、实施外斜视矫正术年龄、手术方式与手术效果等。主要指标 发病年龄、屈光度、斜视角度、眼球运动、手术方式、手术效果。结果 本组17例患者中,11例1岁以前发现内斜视;实施内斜视矫正术年龄2~19岁,平均（6.79±5.39）岁（中位数年龄4岁）;连续性外斜视发病年龄为3~21岁,平均（9.00±4.97）岁（中位数年龄8岁）。屈光度为-1.0 ~ +2.0 D者9例（52.9%）,＞+2.0 D者7例（41.2%）,1例（5.9%）为高度近视（-10.0 D）。4例伴有单眼弱视;13例无双眼视功能;平均外斜视角度看近为45△（15△ ~ 95△）,看远为50△（20△ ~ 105△）;5例（29.4%）内转受限。3例行内直肌复位术,14例行内直肌复位术+外直肌后徙术。术后眼位14例（82.4%）正位,欠矫3例,1例术后半年眼位发生外斜漂移现象;术后三级视功能较术前有不同程度提高。结论 本组连续性外斜视与内斜视发病年龄小,内斜视矫正手术实施年龄小,常伴有单眼弱视、无双眼视功能等多种因素有关;对连续性外斜视进行个性化的手术设计,效果较好。（眼科, 2013, 22： 324-327）     

Minimal angle horizontal strabismus detectable by lay observers.

PURPOSE: Patients with socially significant strabismus may be at risk for certain psychosocial consequences. However, the magnitude at which strabismus becomes socially significant is ill defined. Suggested criteria for socially significant strabismus can be found in the literature, but they are rarely, if ever, referenced. The purpose of this study is to further define the magnitude at which strabismus becomes socially significant according to lay observers. METHODS: Strabismus was simulated using photo manipulation and off-center fixation. Horizontal deviations were created in 3Delta steps up to 24Delta. One model was used for all photos. The photos were presented in random order to non-health care professionals (N = 58). Participants were instructed to view each picture and determine: "yes, this person has an eye turn" or "no, this person does not have an eye turn." A chi test was used for analysis. RESULTS.: There was an increase in the likelihood of strabismus detection as the size of the angle increased for exotropia and esotropia. Overall, exotropia was easier to identify than esotropia. For esotropia, a dramatic increase in detectability occurred between 9Delta (47.41% detection; p = 0.001) and 12Delta (67.24% detection; p = 0.001), with 70% detection being achieved at 14.5Delta. A significant increase in detection of exotropia occurred between 6Delta (60.34% detection; p = 0.001) and 9Delta (77.59% detection; p = 0.001), with 70% detection achieved at 8Delta. CONCLUSIONS: Our results suggest that exotropia is easier for lay observers to detect than esotropia, with the critical magnitude (70% detection) being 14.5Delta for esotropia and 8Delta for exotropia. This refutes generally accepted beliefs that esotropia is easier to detect than exotropia. Additional studies are needed to look at the effect of ethnicity, sex, and age. Multiple models should be used to reduce the possible influence of distinct facial characteristics and increase the generalizability of the results.     

Form vision deprivation amblyopia: Further observations

Nine cases of esotropia occurring in deprivation amblyopia, where exotropia rather than esotropia is usually found, showed a refractive error of hypermetropia. This fact suggested that an accommodative factor is largely responsible for the development of esotropia. A- or V-pattern strabismus was encountered in a higher incidence in deprivation amblyopia than in ordinary strabismus. Pattern-reversal VEP showed more prominent abnormality than flash VEP did. Studies of the sensitive period of the visual system revealed that the sensitivity is likely to be low for a month or two after birth and increases with a peak around the 18th month of age, decreasing thereafter with a waning slope to the end of the 8th year of life.Dedicated to Dr. G.K. von Noorden on the occasion of his 60th birthday     

Congenital esotropia with a bifixation result report of a case

Surgical alignment of the eyes in congenital esotropia within the first two years of age can result in the development of binocular vision. With one exception, reported here, the binocular vision has been extramacular and never macular. In this one case the patient was proven to be a bifixator. This is such an unusual outcome that the diagnosis of congenital esotropia must be questioned. Moreover, dissociated double hypertropia was not found in this case.