can intermittent exotropia be curedcan intermittent exotropia be cured

and transmitted securely. Observations on the surgical overcorrection of childhood intermittent exotropia. He substituted simulated divergence excess to tenacious proximal fusion, and divided convergence insufficiency type to low AC/A ratio, fusional convergence insufficiency, and pseudoconvergence insufficiency [50]. Intermittent exotropia causes the eye to sometimes move outward, often when you're tired, sick, daydreaming, or looking in the distance. They suggested a surgical dose of 9.0 mm with ULR for X(T) of 20 PD. Six of the 22 patients with a high AC/A ratio showed esotropia at near after surgery. Wright KW. Intermittent exotropia is not present all the time. Can exotropia be cured? - Studybuff.com I am now probably less upbeat with parents about the results of surgery than I was previously. They concluded that after BLR, consecutive esodeviation continuously decreased, and 82% of the patients were weaned off prism glasses after 3 years. Kim HJ, Choi DG. Notably, lateral rectus advancement was effective irrespective of abduction limitation. Timing of surgery for primary exotropia in children. Haldi BA. [25,26] found no relationship between the preoperative deviation angle and surgical outcome in both RR and BLR. The prism-weaned group showed a larger preoperative constant deviation and anisometropia, and higher exodrift. Accommodative ability in exotropia: predictive value of surgical success. Intermittent exotropia (X (T)) is one of the most common type of strabismus in children as well as adults, especially in the Asian and South Asian populations. Raab EL, Parks MM. Pediatric Eye Disease Investigator Group [55] reported a multicenter RCT, including 197 children aged 3 to 11 years of age, with 15 to 40 PD of basic type X(T), and near stereoacuity 400 arcsecond. Surgical management of intermittent exotropia with high AC/A ratio. Its a problem with the brain. Yam JC, Chong GS, Wu PK, et al. In contrast, Kim et al. Failure to discover the maximum angle of deviation may contribute to the recurrence [16] and identifying the maximum angle of deviation may help decrease the recurrence rate. Lim et al. After 1 year, they found similar improvements in near deviation, while, at distance, the slanted BLR showed slightly better outcomes compared with the other two procedures. Thirty-four patients (32%) were weaned off the prism glasses within 1 year. Notably, no patient lost stereopsis because of overcorrection. [103] reported that surgeries performed at <7 years of age could result in better motor (exodeviation of <10 PD) and sensory outcomes as well as fewer instances of reoperations. in the United Kingdom,1 supports Dr. Rosenbaums premise that intermittent exotropia is not fully understood. This is not just with respect to a childs age at surgery but also with the degree of deterioration or lack of control required before you initiate surgery. He added that even when surgical intervention is warranted, there is no consensus about the best procedure to treat the condition. Scott WE, Keech R, Mash AJ. Farid MF, Abdelbaset EA. Management decisions in intermittent distance exotropia vary and lack well-defined clinical guidelines. Practical aspects of the adjustable suture technique for strabismus surgery. The success rates and incidence of recurrence were not significantly different between BMR and UMR resection; however, the incidence of overcorrection was significantly higher with BMR resection. The modified RR was significantly more successful than the augmented BLR in the management of the true/masked convergence insufficiency type X(T). Distance-near disparity reduced more with augmented BLR and slanted BLR than with modified RR. Intermittent exotropia is the most common form of exotropia. Comparison of bilateral lateral rectus recession and unilateral recession resection for basic type intermittent exotropia in children. Stability of the postoperative alignment in adjustable-suture strabismus surgery. Kushner BJ. 1 Getting Medical Attention 2 Exercising Your Eyes Other Sections Tips and Warnings Related Articles References Co-authored by David Felsted, DO and Jessica Gibson Last Updated: June 28, 2023 References If you've struggled with keeping your eyes aligned, you probably have a form of strabismus (eye misalignment) called exotropia. Asjes-Tydeman et al. An initial overcorrection of 17 to 20 PD might be acceptable [4,7,14]; however, risks of consecutive esotropia and monofixation syndrome exist, which can lead to loss of stereopsis and amblyopia especially in young children [13,23]. In contrast, Zou et al. The corresponding success rates ranged from 18% to 92%, and most studies concluded that the duration of consecutive esotropia or diplopia was shorter than 4 weeks, with a tendency to exodrift with time following any of the surgical methods. 2 Hoyt CS, Pesic A. Br J Ophthalmol. These articles challenge some of the dogma that has guided the management of children with this condition in the past. Lee EK, Yang HK, Hwang JM. Gurlu and Erda [49] found that the distance deviation angle stabilized after 1-hour occlusion test and the near deviation angle after 3-hour occlusion. Operating on one muscle could spare other muscles for reoperation and could reduce the surgery time as well as the risks of scleral perforation or endophthalmitis. Lee et al. Choi J, Chang JW, Kim SJ, et al. Kim SH, Choi YJ. According to the American Academy of Ophthalmology, intermittent esotropia is normal up to 3 months after birth and resolves on its own. Comparison of surgery versus observation for small angle intermittent exotropia. By Perrine Juillion / February 1, 2023 Exotropia is common and treatable, especially when diagnosed and corrected at a young age. The undercorrection rate at distance was 23% with augmented BLR and slanted BLR, and 57% after modified RR. Long term surgical outcomes of unilateral recession-resection versus bilateral lateral rectus recession in basic-type intermittent exotropia in children. Outcome study of unilateral lateral rectus recession for small to moderate angle intermittent exotropia in children. Exotropia - American Association for Pediatric Ophthalmology - AAPOS Chougule et al. Lyu IJ, Park KA, Oh SY. Pratt-Johnson JA, Barlow JM, Tillson G. Early surgery in intermittent exotropia. Arnoldi KA, Reynolds JD. Simulated divergence excess type X(T) is designated when the near deviation angle increases with occlusion or on adding +3.00 lens [47]. They also found that recurrences were most common within postoperative 6 months, and continued to increase with RR, but not with BLR. Some of us advocate early surgery, whereas others advocate waiting as long as possible. Ekdawi et al. This helps to reduce small amounts of esotropia. Esotropia: Types, Causes & Treatment - Cleveland Clinic Intermittent exotropia is the most common type of the condition. Recurrence of X(T) is common after surgery, and the recurrence rates increase over time [23]. Strabismus (Misaligned Eyes): Symptoms, Causes & Treatment Transient intermittent exotropia is sometimes seen in the first 4 - 6 weeks of life and, if mild, can resolve spontaneously by 6 - 8 weeks of age. Diplopia with consecutive esotropia at distance resolved after an average of 2.7 months. Awadein et al. Kim and Choi [119] reported that the divergence excess type X(T), amblyopia, BLR, esodeviation of 20 PD at postoperative day 1, younger age at diagnosis and surgery, and shorter duration from onset to surgery were risk factors for consecutive esotropia. By about 4 months of age, the eyes should be aligned and able to focus. Han et al. [57] reported that RR with lateral rectus recession 9 mm and medial RR 6.5 mm in X(T) of 40 PD at an average did not induce lateral incomitance over 5 PD or postoperative diplopia. Long-term outcomes of unilateral lateral rectus recession versus recess-resect for intermittent exotropia of 20, 25 prism diopters. Surgical dose-effect relationship increased with the preoperative deviation angle and amount of muscle advancement; therefore, reducing the amount of muscle advancement with larger angle deviations should be considered. In contrast, Leow et al. Han JM, Yang HK, Hwang JM. One or both eyes turn out toward the ear occasionally. [36] compared the long-term effects of BMR to UMR resection for recurrent exotropia of 20 to 30 PD with a minimum follow-up of 5 years. Largest angle to target in surgery for intermittent exotropia. They suggested that the largest angle ever measured should be the target angle for surgery [16]. Esotropia can be monocular (involves one eye) or binocular (involves both eyes). Before In conclusion, although slanted BMR resection has little risk of consecutive esotropia at distance, it was associated with a long-term unsatisfactory chance of recurrence. Wang L, Wu Q, Kong X, et al. How is strabismus treated? Surgical therapy of convergence insufficiency. Kim et al. [29] also reported that a smaller angle of deviation correlated with a smaller postoperative drift after BLR. Each child was examined at one of 26 hospital ophthalmology clinics between May 2005 and December 2006. How to Fix Exotropia: 9 Steps (with Pictures) - wikiHow Somer D, Demirci S, Cinar FG, et al. [32] also found higher cumulative success rates with divergence excess type compared to the basic type after augmented BLR. That leaves you waiting until they are older before you do the surgery. Dr. Clarke believes that, in general, pediatric ophthalmologists were more optimistic about being able to successfully correct intermittent exotropia 10 or 20 years ago than they are today. Long-term surgical outcomes of bilateral vs. unilateral medial rectus resection for recurrent exotropia. Lee and Kim [113] also found that 5% (13 of 284) of the patients developed consecutive esotropia after showing orthotropia or exodeviation at postoperative 1 month. Increasing the surgical dosage of MR resection by 1 mm improved the long-term surgical results compared to the original dosage without significant differences in overcorrection [34]. Kim JY, Lee SJ. Prevalence of and early-life influences on childhood strabismus: findings from the Millennium Cohort Study. Decreased accommodative response in the nondominant eye of patients with intermittent exotropia. http://creativecommons.org/licenses/by-nc/4.0/. Kim et al. Kim H, Yang HK, Hwang JM. Augmented surgical amounts for intermittent exotropia to prevent recurrence. However, few patients may manifest delayed consecutive esotropia after showing orthotropia to exotropia at postoperative 1 month, especially after BLR [112,113]. sharing sensitive information, make sure youre on a federal Kushner [51] suggested that increasing the dose of BLR might be beneficial for patients with basic type X(T). Niederecker O, Scott WE. Exotropia (Eye Misalignment): Causes, Types, and Treatment Options It accounts for 25 percent of all ocular misalignment cases in young children. However, they did not designate the X(T) types in their study. Chia et al. Maruo et al. They defined the suboptimal surgical outcome as exotropia 10 PD to constant esotropia 6 PD at distance or near with simultaneous prism cover test, loss of two octaves or more of stereoacuity from the baseline, or reoperation without meeting any of these criteria. The overcorrection rate was still significantly higher with BMR resection (35% vs. 15%, p = 0.039). Cause of intermittent exotropia The cause of this condition is not known. Interventions for convergence insufficiency: a network meta-analysis. Kim HJ, Kim D, Choi DG. Lee and Hwang [28] administered prism glasses in 110 patients with consecutive esodeviation of 5 PD from 4 weeks after RR. Yang et al. The small number of patients as well as the small preoperative X(T) <10 PD at distance should be considered with the study by Biedner [68]. Overcorrecting minus lens or bifocal glasses were attempted in the remaining 16 patients, and most of them showed normal AC/A ratio after 18 years of age. A lot of kids go through childhood having intermittent sessions of these conservative measures and dont require further treatment. There was no recurrence of exotropia. Treatment of X(T) includes occlusion, use of overminus lens, and surgery [2]. Five years later, the success rate (54% with BLR vs. 42% with RR) as well as the reoperation rate (24% with BLR vs. 34% with RR) was observed to be comparable. They are also known as near point of convergence exercises.. [112] found that 79% of consecutive esotropia were patients who underwent BLR that were orthotropic after 1 month, then later developed esodeviation within 7.4 6.0 months (range, 229 months). Intermittent exotropia. Chia et al. It causes one or both eyes to turn out toward the ear, typically when a child looks into the distance, daydreams, is tired, or is in bright sunlight. Eye Exercises for Strabismus - WebMD Gezer et al. New Research Sheds Light on Intermittent Exotropia, Instruction Courses and Skills Transfer Labs, Program Participant and Faculty Guidelines, LEO Continuing Education Recognition Award, What Practices Are Saying About the Registry, Provider Enrollment, Chain and Ownership System (PECOS), Subspecialty/Specialized Interest Society Directory, Subspecialty/Specialized Interest Society Meetings, Minority Ophthalmology Mentoring Campaign, Global Programs and Resources for National Societies, Dr. Richard Mills' Opinions, 2002 to 2016, International Society of Refractive Surgery. Successful motor outcome (exodeviation of 10 PD to esodeviation of 5 PD) was achieved in 67% of the patients, and stereoacuity was improved or maintained in 79% of the patients. Dr. Donahue expressed some concern that three years of follow-up may not be sufficient to evaluate recurrence. Chia et al. Jeon H, Jung J, Choi H. Long-term surgical outcomes of early surgery for intermittent exotropia in children less than 4 years of age. Exotropia can also be classified by causeit can be either congenital (present at birth; also known as infantile exotropia) or acquired. Long-standing consecutive esotropia could be managed with MR recession or LR advancement. Tibrewal S, Singh N, Bhuiyan MI, et al. Surgical experiences with two-muscle surgery for the treatment of intermittent exotropia. Five months after immediate overcorrection, five out of six patients showed exophoria, and one showed exodeviation of 23 PD at near. Timely surgery in intermittent and constant exotropia for superior sensory outcome. Unilateral lateral rectus recession is an effective surgery for intermittent exotropia in young children. With an increased surgical dosage, the recurrence rate (7.0 %) at postoperative 2 years was remarkably lower compared to the recurrence rate (range, 38%61%) reported in the previous studies [25,27,62,63]. [44] revealed that preoperative monocular occlusion increased near deviation angle, especially in hyperopes. Clinical manifestations of delayed-onset consecutive esotropia after surgical correction of intermittent exotropia. Therefore, surgeons should recognize the possibility of delayed development of consecutive esotropia. Nusz KJ, Mohney BG, Diehl NN. [54] evaluated the accommodative response with dynamic retinoscopy and found better results with RR (13 of 18, 72%) than with BLR (5 of 14, 36%) in 32 patients with unequal accommodation. Often, your eye will alternate between looking straight and turning outward. Yang HK, Hwang JM. Long-term surgical outcomes of augmented bilateral lateral rectus recession in children with intermittent exotropia. The basic type is the X(T) with less than 10 PD difference between the deviation angles at distance and at near [47]. Yang X, Man TT, Tian QX, et al. Accessibility Later, Sung et al. A meta-analysis concluded that RR showed a higher success rate and lower undercorrection than ULR for X(T) 20 PD. Vision therapy for intermittent exotropia: A case series - PMC Sean P. Donahue, MD, PhD, professor and vice chairman of ophthalmology at Vanderbilt University School of Medicine, addressed the many unknowns inherent in treating young patients with intermittent exotropia. In contrast, RR and ULR showed similar results for X(T) of 20 to 25 PD [60]. Lee SY, Hyun Kim J, Thacker NM. HHS Vulnerability Disclosure, Help Surgical correction of consecutive esotropia with unilateral medial rectus recession. Distance/near differences in intermittent exotropia. It occurs after six months of age. Kim TW, Kim JH, Hwang JM. They suggested that the limbus-insertion distance of LR could be a predictor of the recession effect [109]. Esotropia is an eye condition that refers to either one or both of your eyes pointing inward. At 5 years after surgery, the success rates were not significantly different between the BMR and UMR resection (57% vs. 62%); similar findings were observed in the recurrence rates. . Chia A, Seenyen L, Long QB. Feretis et al. Intermittent exotropia surgery: results in different age groups Infantile esotropia: In this type of strabismus, infants show a significant inward turning of both eyes before they're 6 months old. An initial overcorrection 20 PD decreased to 10 PD at distance and at near within postoperative 4 weeks in 72% (49 of 68) of the patients. These children's eyes tend to turn inward whether the focus is on something up close or in . Selective surgery for intermittent exotropia based on distance/near differences. Infantile esotropia: With this form of squint, children younger than 6 months old are typically affected. Kraft et al. Burian [47] classified X(T) into four different types: basic, divergence excess, simulated divergence excess, and convergence insufficiency. Interestingly, 39% (9 of 23) of the divergence excess type and 20% (3 of 15) of the convergence insufficiency type cases were converted to other types after the 1-day occlusion test [44]. 2012;96(10):1291-1295. Most of the kids who underwent surgery were losing vision or losing depth perception, but their eyes were not drifting out all the time., Dr. Epley added that the proportion of children in the study who had surgery was surprisingly low. The debate over the better surgical procedure for X(T) may continue and differ according to the experience of each surgeon. It can usually be managed or treated, but treatment will vary based on type and severity. Burian [47] recommended BLR for divergence excess type as well as simulated divergence excess type X(T). Souza-Dias C, Uesugui CF. But a recent study in the British Journal of Ophthalmology(BJO)1 and an accompanying editorial2 call into question the notion that intermittent exotropia is straightforward or fully understood. Others believe that you should weaken the lateral rectus and tighten the medial rectus of the same eyethe recess-resect procedure. Nelson LB, Bacal DA, Burke MJ. It is an acquired exotropia that manifests as an intermittent outward deviation of the eyes. Acquired Esotropia Acquired esotropia occurs later in life. For example, he noted that the natural history of the disorder had not been adequately defined and that it was not clear whether the condition does in fact deteriorate over time, as has been widely believed. The site is secure. But a recent study in the British Journal of Ophthalmology ( BJO) 1 and an accompanying editorial 2 call into question the notion that intermittent exotropia is straightforward or fully understood. [89] performed a ULR of 11.5 to 12.0 mm on the nondominant eye in 10 patients with X(T) of 14 to 16 PD. A meta-analysis, including 454 patients of three RCTs and three retrospective studies found a higher success rate and lower recurrence with RR within a year postoperatively in basic type X(T) [59]. Park SH, Kim HK, Jung YH, et al. Factors affecting residual exotropia after two muscle surgery for intermittent exotropia. Cumulative probability of suboptimal surgical outcome was 46% (43 of 101) after BLR versus 37% (33 of 96) after RR. Intermittent Exotropia Article - StatPearls Kushner [51] reported that the surgical result after BLR is known to be better in simulated divergence excess type than in basic type X(T). Intermittent exotropia: In this type of strabismus, one eye will fixate (concentrate) on a target while the other eye points outward. Pineles SL, Ela-Dalman N, Zvansky AG, et al. This topic will focus specifically on intermittent exotropia, which is the most common type of manifest exodeviation. BLR is more likely to result in relapse within postoperative 1 year than RR (29.3% vs. 7.0%, p < 0.001). [52] found similar results in the divergence excess type and basic type X(T). 1 Nevertheless, . These kids may do well for three years, but the problem with intermittent exotropia is that it is not an eye problem or an eye muscle problem. Finally, orthotropia to exodeviation and/or esodeviation 10 PD was achieved in 71% (48 of 68), and exodeviations >10 PD in 16% (11 of 68) of the patients at distance or at near. [75] reported that 1-mm different slanted BLR was superior to the standard BLR in reducing X(T) at distance and at near as well as distance-near differences in the 11 of 12 patients. [114] reported that a misalignment of 10 PD increased from 54% at 5 years to 76% at 10 years, and further increased to 86%, 15 years later. Federal government websites often end in .gov or .mil. Small-angle X(T) could be treated with ULR, BLR, or RR. The purpose of this review is to provide an insight on the surgical treatment of X(T). Unilateral surgery for exotropia with convergence weakness. Consecutive esotropia after surgery for intermittent exotropia: the clinical course and factors associated with the onset. An average period of prism wearing was 21 months, and the esodeviation decreased at the rate of 2.9 PD in 6 months. Overaction of all oblique muscles may disappear following the surgical procedures on horizontal recuts muscles [88]. Kim DH, Yang HK, Hwang JM. What does a person with exotropia see? Postoperative changes of intermittent exotropia type as classified by 1-hour monocular occlusion. Eye Health Reference Eye Exercises for Strabismus Written by Angela Nelson Medically Reviewed by Whitney Seltman, OD on November 07, 2022 Eye Exercises as Therapy What if Vision Therapy. The long-term survival analysis of bilateral lateral rectus recession versus unilateral recession-resection for intermittent exotropia. But some kids will decompensate and lose vision or depth perception, and that is my cue to move on to something more interventional. Br J Ophthalmol. Sung JY, Yang HK, Hwang JM. Graeber and Hunter [56] reported that asymmetric surgery including RR resulted in larger incomitance than symmetric surgery, while preoperative incomitance more likely resolved with asymmetric than symmetric surgery. Kraft SP, Levin AV, Enzenauer RW. Although RR achieved better surgical outcomes in three of the four RCTs, several retrospective studies reported better or comparable surgical outcomes of BLR versus RR. Some patients with X(T) may show a variable target angle before surgery [45]. Abduction limitation was minimal for ULR of up to 12 mm. Moreover, the recurrence occurred until 2 to 3 years after BLR, while RR caused a greater exodrift for postoperative 1 year. Therefore, 1-day occlusion tests may be useful in patients with divergence excess or convergence insufficiency type X(T), as well as in hyperopes. Surgical management of convergence insufficiency. As a library, NLM provides access to scientific literature. Farid and Abdelbaset [71] prospectively compared three procedures of slanted BLR (upper horn based on distance deviation angle and lower horn based on near deviation angle in 22 patients), modified RR (LR recession based on distance deviation angle and MR resection based on near deviation angle in 23 patients), and augmented BLR based on near deviation in 22 patients. Pritchard C. Intermittent exotropia: how do they turn out? In turn, your vision could become aligned. Kushner and Morton [50] classified divergence excess type X(T) as a high ratio of accommodative convergence (AC) to accommodation (A) ratio and proximal convergence. Oh SY, Choi HY, Lee JY, et al. Further, the clinical indications for surgery remained unclear; and the long-term outcomes of surgical treatment were sometimes disappointing, with high rates of persistent or recurrent exodeviations and consecutive esodeviations. It involves one eye pointing outward while the other focuses on an object. [79] reported the results of modified RR in 14 patients with a near-distance difference 8 PD. No significant difference in terms of overcorrection rates was observed between BLR and RR [59]. Burian HM. [25] reported that the recurrence rate after RR continuously increased from 5.3% at 1 month, 16.0% at 3 months, 27.6% at 6 months, 41.9% at 12 months, 60.7% at 2 years, 70.8% at 3 years, 74.5% at 4 years, and 77.9% at 5 years. Unilateral lateral rectus recessions in exotropia. [18] reported better results with RR (55 of 66, 83%) than with BLR (28 of 58, 48%) in exotropes with a dominant eye; however, the overcorrection rate was significantly higher with RR (7.6% vs. 0%), especially with poor preoperative stereopsis. Some people believe that the best approach is to do symmetric surgery because each eye sees well and each eye drifts, said Dr. Donahue. Intermittent exotropia: surgical results in different age groups. But we dont know whether one procedure has a higher risk of initial overcorrection or if that overcorrection can cause deterioration in binocular vision or might even be helpful in ensuring long-term stability. 3 Eye Exercises for Strabismus | Healthline Multivariate analysis revealed that initial postoperative esodeviation of 18 PD at 1 month after exotropia surgery was a predictor for success. Another meta-analysis, including nine studies found that the success rate of RR was better than that of BLR for up to 2 years; however, after 2 years, the success rate of BLR became higher than that of RR with a lower undercorrection rate [60]. Surgical treatment of X(T) may vary according to the type of X(T). They concluded that an initial overcorrection 20 PD mostly reduced to 10 PD within 4 weeks, and reoperations for consecutive esotropia were necessary in 6% of the patients. Intermittent exotropia. They suggested that augmentation according to age could improve the surgical outcome of X(T). [110] reported that a larger preoperative near deviation angle >16 PD and a larger initial postoperative exodeviation of >5 PD at distance were predictors of recurrence in 92 patients with X(T) 25 PD after ULR of 10 mm at more than postoperative 2 years. But we all believe that about a third of these kids will end up having surgery at some point, and some people quote a higher proportion than that., Dr. Epleys approach is to try conservative measures first, provided that the child is not losing vision, can still see normally, and has not lost stereopsis. Long-term outcome of patients with large overcorrection following surgery for exotropia. [109] revealed that the limbus-insertion distance of LR was significantly correlated with dose-response effects. official website and that any information you provide is encrypted Intermittent exotropia is the most common form of exotropia and it is estimated that approximately 3% of Chinese teenagers suffer from this condition. Early surgery may help develop better binocular vision [102104], but may also pose a risk of developing amblyopia to children with immature visual system because of the postoperative overcorrection [105]. Another option for managing the persistent consecutive esotropia could be botulinum toxin injection with or without electromyographic guidance. Pathai S, Cumberland PM, Rahi JS. [117] administered prism glasses in 39 patients with esodeviation of 5 PD from 4 weeks after BLR. Bilateral lateral rectus muscle recession with medial rectus pulley fixation for divergence excess intermittent exotropia with high AC/A ratio. Furthermore, it should be determined whether the surgical dose could be performed based on the largest angle ever measured or the most common or final angle measured, when preoperative angles of X(T) were inconsistent. Reduction of the surgical dose in patients younger than 7 years of age resulted in no significant surgical outcomes; however, increasing the surgical dose in older patients >12 years of age significantly increased the success rate [101]. Kim et al. Treatment of intermittent exotropia. There are a few limitations to compare the surgical outcomes between BLR and RR because of significant differences among the studies, including ethnicity, number of patients, variable classifications of X(T), control of X(T), deviation angles, types of surgical procedure, surgical doses, and definitions of surgical success (esodeviation/exodeviation of 5 to 10 prism diopters [PD]), as well as duration of follow-up. Comparison of long-term surgical outcomes of 2-muscle surgery in children with large-angle exotropia: bilateral vs unilateral.