Accommodative esotropia following surgical treatment of infantile esotropia: frequency and risk factors

Purpose: We aimed to examine the frequency of and risk factors for the development of accommodative esotropia following surgical treatment for infantile esotropia. Methods: A total of 29 children were recruited. Potential risk factors for the development of accommodative esotropia included: sex; angle of deviation at initial and final visits; cycloplegic refractive error at initial and final visits; increase in hyperopia; amblyopia; amblyopia treatment; age at surgical treatment; pre‐ and postoperative latent nystagmus; dissociated vertical deviation or inferior oblique muscle overaction; additional surgical procedures; unstable alignment, and binocular sensory status. Results: Overall, 14 (48.2%) of 29 children developed accommodative esotropia during the 36‐ to 132‐month postoperative follow‐up period. Twelve (85.7%) of the 14 patients developed refractive accommodative esotropia and two developed non‐refractive accommodative esotropia. The onset of accommodative esotropia occurred at a mean of 8.8 months (range 6–24 months) after the initial surgical alignment. This corresponded to a mean age of onset for accommodative esotropia of 43.2 months. We determined that, among children with infantile esotropia, those who had hyperopia of ≥ 3.0 D and increasing hyperopia after surgery and those who did not develop dissociated vertical deviation during the follow‐up period were more likely to develop accommodative esotropia. Conclusions: Children who have the established risk factors should be followed closely for the development of accommodative esotropia. The treatment of these children with appropriate glasses may prevent the development of adverse effects of accommodative esotropia on sensory and motor functions.     

儿童部分调节性内斜视的手术治疗

目的 探讨儿童部分调节性内斜视的手术时机、手术量及手术方式。方法 对38例部分调节性内斜视进行手术，手术量按裸眼和戴镜后斜视度平均值做斜视度的矫正。手术方式按远近斜视度来设计：辐辏过强型者行内直肌徙后术；基本型者行内外直肌手术；分开不足型者行外直肌缩短术。结果 38例中治愈34例占89.5％，4例良好占10．5％，21例术后获得立体视。结论 对于部分调节性内斜视由于存在调节与非调节因素，先从调节因素着手，戴全矫镜；与调节因素无关非调节因素存在的内斜，按戴镜以及裸眼平均斜视度设计手术量，以矫正眼位并尽可能恢复双眼视功能。     

Risk factors for the development of accommodative esotropia following treatment for infantile esotropia.

PURPOSE: One aim of the study was to determine whether accommodative esotropia after surgical alignment in infantile esotropia occurs because a pre-existing accommodative component is unmasked at the time of surgery or whether it occurs as a sequela of infantile esotropia. A second aim of the present study was to examine risk factors for accommodative esotropia after surgery for infantile esotropia. METHODS: A total of 80 consecutive patients who were enrolled in a prospective study of infantile esotropia had been followed for more than 4 years and had achieved orthoposition were included. Twelve potential risk factors were examined: age at onset, initial esodeviation, initial refractive error, age at alignment, delay in alignment, presurgical glasses, amblyopia, additional surgical procedures, unstable alignment, increase in hypermetropia, peripheral fusion, and stereopsis. Mantel-Haenszel odds ratios were computed for each factor and were corrected to relative risks. RESULTS: Overall, 48 of 80 children (60%) developed accommodative esotropia at a mean age of 33 months. Increasing hypermetropia, delay in alignment, and poor stereopsis posed significant risks for accommodative esotropia. The remaining 9 factors were not associated with increased risk for accommodative esotropia. CONCLUSIONS: Accommodative esotropia is unlikely to be a pre-existing condition in most cases because the mean age of onset was 23 months postoperative and the prevalence of preoperative hypermetropia greater than +3.00 D was low. Both delay in alignment and stereopsis risk factors may reflect compromised binocular sensory status that allows accommodative esotropia to occur at low to moderate levels of hypermetropia. Identification of children treated for infantile esotropia who are at risk for accommodative esotropia may allow for prevention or early treatment.     

儿童部分调节性内斜视的手术探讨

目的探讨儿童部分调节性内斜视的手术时机，手术量。方法对35例部分词节性内斜视的患儿戴全矫眼镜半年以后，手术矫治与调节因素无关的非调节因素所致的内斜视。手术量按裸眼和戴镜后斜视度的平均值设计。结果35例中．眼位矫正满意32例占91．43％，良好3例占8．57％；功能治愈有立体视19例占54．29％。结论儿童部分调节性内斜视，其由解剖因素所致的斜视需手术矫正。当患儿戴全矫眼镜半年眼位仍不能恢复正位时，可尽早手术矫治其残存的内斜度，手术量按裸眼与戴镜平均斜视度设计，术后由于调节因素所致内斜仍需配镜矫正。     

Clinical features of comitant strabismus related to family history of strabismus or abnormalities in pregnancy and delivery

PURPOSE: To elucidate the genetic or environmental background for clinical features in the three major types of comitant strabismus. METHODS: Interview based on a questionnaire asking background factors such as family history of strabismus and abnormalities in pregnancy and delivery was conducted with 101 consecutive patients with infantile esotropia (5-180 months of age), 83 with accommodative or partially accommodative esotropia (6-201 months of age), and 143 with intermittent exotropia (3-216 months of age) seen during 7 months from May to November 1998. The clinical features of strabismus obtained from medical records were analyzed statistically by logistic regression to determine their relation with these background factors. RESULTS: In infantile esotropia, patients with family history of strabismus had a significantly higher chance of showing latent nystagmus (odds ratio, 3.553; 95% confidence interval [CI], 1.077-11.717; P =.0373, logistic regression analysis). In a subgroup of 40 patients with infantile esotropia whose birth followed no abnormalities in pregnancy or delivery, patients with family history of strabismus had a significantly higher chance of showing inferior oblique muscle overaction (odds ratio, 7.714; 95% CI, 1.246-47.761; P =.0280), dissociated vertical deviation (odds ratio, 6.667; 95% CI, 1.176-37.787; P =.0321), and latent nystagmus (odds ratio, 7.333; 95% CI, 1.168-46.060; P =.0336). In accommodative or partially accommodative esotropia and intermittent exotropia, no relation was found between the clinical features and the background factors. CONCLUSIONS: Inferior oblique muscle overaction, dissociated vertical deviation, and latent nystagmus in infantile esotropia might have a genetic background.     

Relation between preoperative hyperopia and surgical outcome in infantile esotropia

AIM: To evaluate the relation between preoperative hyperopia and surgical outcomes of infantile esotropia in patients younger than 24 months of age. METHODS: Medical records of patients who underwent bilateral medial rectus muscle recession for infantile esotropia between November 1, 2002 and December 1, 2011 were retrospectively reviewed. Patients were divided into two groups according to the degree of preoperative hyperopia. Group I had less than +3.0 diopter (D) of hyperopia and group II had between +3.0 and +5.0 D of hyperopia. Postoperative alignments were evaluated 1wk, 3, 6mo, and 1y after surgery. Following the 1-year postoperative visit, patients were monitored yearly. Relationships between preoperative factors including hyperopia and postoperative outcomes were evaluated. RESULTS: Forty-six patients were included, with 33 patients in group I and 13 patients in group II. The preoperative mean refractive error was +0.88 D in group I and +3.45 D in group II. Surgical outcomes were not significantly different between groups at any postoperative time point examined. Cumulative probability of surgical success, prevalence of inferior oblique overaction, dissociated vertical deviation, and re-operation rate were not significantly different between groups. CONCLUSION: Preoperative moderate hyperopia (less than +5.0 D) did not affect the surgical outcome of infantile esotropia. Therefore, the surgical correction of esotropia should be considered when the angle of esodeviation is unchanged following hyperopia correction, even in children with moderate hyperopia.     

Is it possible to differentiate early-onset accommodative esotropia from early-onset essential esotropia?

PURPOSE: To determine the frequency of > or =2.50 diopter (D) hyperopia in infantile esotropia with onset up to the age of 6 months and by evaluating the treatment results of these cases retrospectively, to find the factors that may help to differentiate early-onset accommodative esotropia from early-onset essential esotropia. METHODS: The charts of 256 patients with infantile esotropia were reviewed. Thirtyseven cases, with hyperopia of > or =2.50 D, no other systemic and neurologic disease, and at least 1 year of follow-up, were included in this study. The age at the start of therapy, refractive error, deviation angle, type of therapy (antiaccommodative therapy, surgery) and the presence of amblyopia, latent nystagmus, inferior oblique overaction, dissociated vertical deviation and cross-fixation were recorded for each case. RESULTS: The prevalence of high hyperopia was found to be 14.4% (37/256) in infantile esotropia. In 18 of the cases (48.6%), antiaccommodative therapy alone was found to be adequate (Group I). In the remaining 19, although antiaccommodative therapy was found to decrease the deviation angle significantly (P<0.001), surgery was also required (Group II). Groups were compared with respect to age at the initial examination, refractive error, deviation angle, presence of amblyopia, anisometropia, and inferior oblique overaction, but no factor could be determined to predict the pure refractive ones (P>0.05). Essential infantile esotropia-associated findings did not help because they are rarely evident at the time of initial diagnosis. CONCLUSIONS: Half of the high hyperopic infantile esotropes could be corrected fully by antiaccommodative therapy alone, while the remaining ones could also benefit significantly. It is strongly recommended to try spectacles at first in the treatment of infantile esotropia with hyperopia > or =2.5 D.     

儿童部分调节性内斜视的手术矫正与立体视觉

为探讨儿童部分调节性内斜视的手术时机，观察了７８例儿童部分调节性内斜视矫正术后的立体视恢复情况；分析各种因素对其立体视恢复的影响。结果：７８例中，５５例术后获得立体视，功能治愈率为７０．５％，且术后立体视的恢复率与术前相比，差异非常显著（ｐ＜０．０１）；早期手术组及具有融合功能组的立体视的恢复率显著高于较晚手术组及无融合功能组（ｐ＜０．０１）；发病越早，术后建立立体视的预后越差。结论：儿童部分调节性内斜视与部分调节因素有关，其由于解剖因素所引起的斜视需手术矫治。从立体视恢复上考虑，当患儿全矫配镜半年眼位仍不能正位时，应尽早手术矫正其残存的内斜度。术中应根据戴全矫眼镜后的眼位决定手术量。术后由于调节因素所致的内斜视仍需配镜矫正。     

Unilateral Recession-Resection Surgery for Infantile Esotropia: Survival of Motor Outcomes and Postoperative Drifts

Purpose: To outline the short- and long-term motor outcomes of unilateral medial rectus muscle recession and lateral rectus muscle resection for the correction of moderate angle infantile esotropia. Methods: A retrospective study of 109 consecutive patients with moderate angle infantile esotropia treated with graded unilateral recession-resection surgery. Criteria for successful motor outcome included alignment ±10Δ from orthophoria. Outcome evaluation was a comparison of successful alignment versus an overcorrection or undercorrection at eight weeks postoperatively as well as on the final follow-up examination. Results: The mean preoperative deviation was 35.5 prism diopters (Δ) and mean follow-up time was 4.9 years. At the eight-week postoperative examination, 99 patients (89.9%) were successfully aligned, as opposed to 75 of 95 patients (78.9%) at the final postoperative visit (P=0.041). There was no statistically significant difference between the rate of early versus late undercorrections (7.3% versus 12.5%, P=0.267) or overcorrections (2.7% versus 8.3%, P=0.125). Ten patients had an esotropic drift over time and 10 patients had an exotropic drift. Recurrent esotropia was associated with high hyperopia and presumed infantile esotropia diagnostic entity. The Kaplan-Meier estimate of survivorship of a successful motor outcome was 75.5% at five years and 71% at 15 years postoperatively. The mean response to surgery was 2.9Δ per mm of muscle recessed and resected and was positively related to the preoperative angle of deviation (R=0.615). Conclusions: The unilateral recession-resection procedure for the correction of infantile esotropia is shown to be associated with a favorable survival of motor outcomes and a relatively balanced rate of undercorrections versus overcorrections tending to be maintained through the follow-up period.     

Three horizontal muscle squint surgery for large angle infantile esotropia

BACKGROUND: To report the long-term outcome of a series of 49 patients who underwent three horizontal muscle squint surgery for large angle infantile esotropia. METHODS; The patient records were retrospectively reviewed of 49 (24 girls [49%], 25 boys) consecutive patients with infantile esotropia of angle > or =60 Delta, who had undergone three horizontal muscle surgery performed by one surgeon (author GG). Surgery consisted of bilateral medial rectus recession combined with graded unilateral lateral rectus resection. Surgeries were carried out over a 6-year period with a mean follow-up period of 32.9 months (3.7-71.8 months). RESULTS: Using Kaplan-Meier life-table analysis, cumulative surgical success (orthotropia +/-10 Delta) was 93.9% at 1 week, 91.8% at 2 and 6 months, 87.7% at 12 and 18 months, 79.9% at 2 years, 77.1% at 3, 4 and 5 years, and 70.6% at 6 years. The mean preoperative deviation was 68.7 Delta. The mean age at surgery was 12.9 months. The failure rate was independent of preoperative deviation. Prevalence of residual esotropia (>10 Delta) varied from 2.0% at 1 week to 17.0% at 6 years. Similarly the prevalence of consecutive exotropia (>10 Delta) varied from 4.0% at 1 week to 12.4% at 6 years. CONCLUSION; Operating in a graded fashion on three horizontal muscles in children with large angle infantile esotropia has a high success rate, even over long-term follow up. Based on the study's results, amounts of surgery for a given angle of strabismus are proposed.     

传统与欠矫手术治疗部分调节性内斜视的比较(英文)

目的:评估传统与欠矫手术治疗部分调节性内斜视患者的效果。方法:将25例具有部分调节性内斜视和正常AC/A的患者随机分为两组,其中13例患者接受传统手术治疗,其余12例患者接受欠矫手术治疗。传统手术是基于远距远视完全矫正所测量的偏差上,而欠矫手术比传统手术标准低20%。所有患者均进行对称性双眼内直肌后退术,术后随访6mo。结果:术后6mo,传统组与欠矫组手术成功率分别为46%和91%(成功标准定义为通过近距和远距远视的完全矫正斜视≤8△)。传统组和欠矫组的手术过矫率分别为54%和9%,两组间差异有统计学意义(P<0.05)。没有残余内斜视。手术成功率或欠矫率与患者的年龄、术前等效球镜均值、术前眼偏斜量无相关性。结论:对于具有正常AC/A的部分调节性内斜视患者,欠矫的双眼内直肌后退术成功率较高,过矫率较低。     

A study of heredity as a risk factor in strabismus

AIMS: Inheritance is recognised to have a part in the aetiology of strabismus but previous studies have not adequately distinguished between different types of strabismus leading to wide variations in reported findings. The aim of this study was to investigate the importance of heredity in different types of strabismus. METHODS: The parents of children attending for treatment of strabismus over a one-month period were interviewed to identify relatives with a history of strabismus. A complete three-generation pedigree was established for 96 index cases who were classified into four groups: infantile esotropia (26 cases), accommodative esotropia (49 cases), anisometropic esotropia (15 cases), and exotropia (six cases). RESULTS: Forty-three of a total of 165 (26.1%) first degree relatives of patients with hypermetropic accommodative esotropia were affected. In contrast, 15 of a total of 101 (14.9%) first degree relatives of patients with infantile esotropia, eight of a total of 66 (12.1%) first degree relatives of patients with anisometropic esotropia, and one of a total of 25 (4%) first degree relatives of patients with exotropia were affected. Analysing the data using logistic regression with a random term for family showed a significantly higher proportion of affected first degree relatives in the accommodative group than in any of the other three diagnostic groups. CONCLUSION: A history of strabismus appears to be more common in hypermetropic accommodative esotropia than in infantile esotropia, anisometropic esotropia or exotropia. More detailed investigation of the role of heredity in the aetiology of accommodative esotropia is needed.     

Outcome in refractive accommodative esotropia

AIM: To examine outcome among children with refractive accommodative esotropia. METHODS: Children with accommodative esotropia associated with hyperopia were included in the study. The features studied were ocular alignment, amblyopia, and the response to treatment, binocular single vision, requirement for surgery, and the change in refraction with age. RESULTS: 103 children with refractive accommodative esotropia were identified. Mean follow up was 4.5 years (range 2-9.5 years). 41 children (39.8%) were fully accommodative (no manifest deviation with full hyperopic correction). The remaining 62 children (60.2%) were partially accommodative. At presentation 61.2% of children were amblyopic in one eye decreasing to 15.5% at the most recent examination. Stereopsis was demonstrated in 89.3% of children at the most recent examination. Mean cycloplegic refraction (dioptres, spherical equivalent) remained stable throughout the follow up period. The mean change in refraction per year was 0.005 dioptres (D) in right eyes (95% CL -0. 0098 to 0.02) and 0.001 D in left eyes (95% CL -0.018 to 0.021). No patients were able to discard their glasses and maintain alignment. CONCLUSIONS: Most children with refractive accommodative esotropia have an excellent outcome in terms of visual acuity and binocular single vision. Current management strategies for this condition result in a marked reduction in the prevalence of amblyopia compared with the prevalence at presentation. The degree of hyperopia, however, remains unchanged with poor prospects for discontinuing glasses wear. The possibility that long term full time glasses wear impedes emmetropisation must be considered. It is also conceivable, however, that these children may behave differently with normal and be predestined to remain hyperopic.     

儿童部分调节性内斜视的治疗及调整缝线在手术中的应用

目的 探讨儿童部分调节性内斜视的术前治疗、手术时机与手术量以及调整缝线在治疗中的应用。设计 回顾性病例系列。研究对象 北京儿童医院眼科接受手术治疗的部分调节性内斜视患者30例。方法 对手术治疗的部分调节性内斜视患者的临床资料进行回顾性分析。患儿术前矫正屈光异常,观察斜视度稳定,并予适当弱视治疗,在双眼视力相当的情况下进行手术,按照裸眼和戴镜斜视度的平均值设计手术量。术中常规使用调整缝线技术,术后早期依据眼位情况决定是否需要调整。术后随访6~15个月。观察眼位及双眼视功能。主要指标 术后眼位、双眼视功能、眼位调整情况。结果 有3例患儿进行了眼位调整,均为过矫,避免了二次手术。末次随访时30例患者中26例（87%）眼位在正位~+8△之间,4例（13%）眼位+10△~+15△。术前能合作行双眼视功能检查者19例,有双眼视功能者2例（11%）。末次随访时能合作双眼视功能检查者21例,有双眼视功能者15例（71%）。结论  内斜视伴有调节因素时应及时全矫配镜,在残余斜视度稳定、双眼矫正视力基本相当后应尽早手术。手术设计根据戴镜与裸眼视近的平均斜视度,调整缝线有助于保证术后早期的眼位满意,降低了二次手术的风险。（眼科, 2013,22: 121-123）     

儿童部分调节性内斜视手术时机的选择及疗效观察

目的：：分析儿童部分调节性内斜视手术时机的选择和疗效观察,为临床治疗提供参考。方法：选取我院儿童部分调节性内斜视手术患者52例为研究对象,依照手术时机不同分为A组10例、B组25例和C组17例,A组患者发病1a内手术治疗,B组患者发病1~3a手术治疗,C组患者发病3a以上手术治疗,分析手术治疗效果。结果：>6岁儿童术后获得立体感比例(83%)显著高于<3岁儿童(30%)(P<0.05);患者术后立体视觉与患者手术时机存在明显相关性, A组(80%)和B组患者有立体感比例(76%)显著高于C组(41%)(P<0.05);A组(90%)、B组治疗优良率(88%)显著高于C组(71%)(P<0.05)。结论：儿童部分调节性内斜视患者应待患儿6岁以后,尽早开展手术治疗,根据斜视度和裸眼视力情况决定手术量。     

Results of Bilateral Medial Rectus Recession for Comitant Esotropia in Patients with Developmental Delay

Purpose: There is paucity of literature on surgical outcomes after strabismus surgery in patients with developmental delay. There is no consensus regarding whether standard surgical tables are applicable to these children. The goal of our study was to determine results of strabismus surgery for esotropia among these children.

Methods: Two retrospective cohorts of patients, with developmental delay (excluding Down syndrome) and without developmental delay, who underwent bimedial recession for comitant eso-deviation between January 2005 and January 2011, meeting our criteria, were selected. Amount of surgery performed in these children was compared with standard table. This comparison gave us operated angle of deviation. This operated angle of deviation was expressed as percentage of preoperative angle of deviation to get amount of surgery performed. Response to surgery was defined as percentage of change in angle of deviation after surgery to the operated angle of deviation. Amount of surgery performed, response to surgery, and results were compared between two groups.

Results: This study included 25 patients with developmental delay and 53 normal children with comitant esotropia. Age, refractive error, and preoperative angle of deviation were comparable in patients with and without developmental delay. Among patients with developmental delay, on average 72.13%?±?16.08 of angle of deviation was operated; response to surgery gained was 134.06%?±?51.62. In the control group, the average amount of surgery done was 89.08%?±?10.83; response gained was 89.83%?±?22.49. Successful outcome (±10 PD of orthophoria) was noted in 60% patients with developmental delay compared to 73.58% in control group. On average 70.67%?±?17.95 angle of deviation was operated in patients with developmental delay with successful outcome.

Conclusion: Surgical outcome in patients with developmental delay is very unpredictable. An exaggerated response to standard amounts of bimedial recession should be anticipated in these patients. Though there was no statistically significant difference, operating for 70.67%?±?17.95 angle of deviation is more likely to be successful.     

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.     

Comparison of hang-back and conventional bimedial rectus recession in infantile esotropia

Purpose

To compare surgical outcome of hang-back and conventional bimedial rectus muscle recession in infantile esotropia.

Patients and methods

The charts of 67 consecutive patients with infantile esotropia who underwent bilateral medial rectus muscle from 1990 through 2005 were retrospectively reviewed. Thirty patients were operated by hang-back technique (group 1) and 37 by conventional bimedial rectus recession in which the tendon was sutured directly to the globe (group 2). In each group, the angle of esotropia (PD - prism diopters) before and 6 months after surgery and the success rate (deviation of ≤10 PD) were documented.

Results

Esotropia improved an average of 39.7 (SD 14.9) PD in group 1 (from a preoperative 42.7 (SD 11.6) PD to 3.0 (SD 8.5) PD postoperatively) and 45.5 (SD 19.3) PD in group 2 (from a preoperative 54.3 (SD 16.8) PD to 8.7 (SD 12.1) PD postoperatively) (p?=?0.18, independent sample t-test). Success rate (defined as deviation of ≤10 PD at 6 months postoperative examination) was 83.3% in group 1 and 70.2% in group 2 (p?=?0.21, Chi-square). Multivariate logistic regression suggests that surgical outcomes are not significantly influenced by age and preoperative angle of esotropia. No complications occurred in both groups.

Conclusion

Hang-back technique is as effective as the conventional bimedial rectus muscle recession in correcting infantile esotropia.     

Childhood esotropia

PURPOSE: To review the most recent studies on childhood esotropia, and to summarize recent changes in treatment approach. RECENT FINDINGS: Constant, large-angle esotropia present in the first few months of life may be suitable for early surgery. Earlier surgical intervention, within the first several months of onset, is associated with better sensory outcomes. Similar findings are true for accommodative esotropia; children treated within the first 4 months of constant esotropia have better outcomes. Refractive surgery has been used successfully in adult patients to treat accommodative esotropia. SUMMARY: New developments pertaining to infantile esotropia have helped clarify the pathophysiology of the condition and the best treatment approaches. Abnormal binocular visual input early in life contributes to poor outcomes in both infantile and accommodative esotropia.     

Surgical outcomes for esotropia in children with high accommodative convergence/accommodation ratio

Purpose:To assess if high accommodative convergence/accommodation (AC/A) ratio impacts surgical outcomes in children with esotropia (ET), and evaluate the appropriate target angle in surgical dosing in the presence of high AC/A ratio.Methods:A retrospective chart review identified patients who underwent primary bilateral medial rectus (BMR) recessions for ET. Patients were excluded if follow-up was ≤2 months. Basic demographic information, visual acuity, stereopsis, alignment, and target angle for surgery were collected. High AC/A was defined as ≥10 prism diopter (Δ) deviation at near compared to distance. Outcome parameters were near and distance deviations ≤10Δ within orthophoria, and/or stereopsis postoperatively. Yates’ continuity correction, unpaired t-test, regression analysis, and one-way ANOVA were used.Results:We identified 103 patients, 23 with high AC/A and 80 with normal AC/A, preoperatively. Mean age was 4.0 ± 2.5 years. Surgical success measured by postoperative alignment was 48% and 45% in the high AC/A and normal AC/A groups, respectively (P = 1.0). There was a statistically significant difference in preoperative near deviation between high AC/A and normal AC/A groups (P = 0.0015); however, there was no significant difference in preoperative distance deviation (P = 0.061). In addition, there was not a significant difference in preoperative or postoperative stereopsis between high AC/A and normal AC/A groups (P = 0.88 and P = 0.44, respectively). There was a significant difference in the normal AC/A and high AC/A groups when target angle was directed toward preoperative near deviation as determined by one-way ANOVA (F = 170.88, P < 0.0001 and F = 14.61, P = 0.0010, respectively).Conclusion:In the setting of ET treated with BMR recession, the presence of high AC/A does not affect surgical success as measured by alignment and stereopsis. In addition, when high AC/A is present, surgical dosing with a target angle toward near deviation was found to yield the best surgical outcomes in our patient population.