Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia

Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia Rehab Rashad Kassem, Rokaya Emad Radwan, Randa El-Mofty, Hala Mostafa Elhilali This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4598867/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 17 Oct, 2024 Read the published version in International Ophthalmology → Version 1 posted 7 You are reading this latest preprint version Abstract Purpose: To compare the effect of unilateral versus bilateral lateral rectus (LR) recession for correction of small to moderate exotropia. Methods: Records of all patients with exotropia (XT) 14 to 35 prism diopters (∆), operated upon by the authors, were included in a retrospective study to compare the effect of unilateral (Group 1) versus bilateral (Group 2) LR recession. The study end-point was the last follow-up visit scheduled at least 3 months postoperatively. A successful outcome was defined as 0 to 10∆ of horizontal tropia. Results: The study included 154 patients (47 in Group 1 and 107 in Group 2). Patients were followed up for 3 to 120 months (26.7+/-24.88). A successful outcome was achieved in 83% in Group 1 and 82.2% in Group 2 ( p =.976), with higher success in group 1 for surgical target angles up to 25∆. All failures in Group 1 were due to undercorrections., while the 17.8% failure rate in Group 2 comprised 15% undercorrections and 2.2% overcorrections ( p =.419). Persistent lateral incomitance was seen in 29.5% in Group 1 versus 2.3% in Groups 2 ( p <.001). Lateral incomitance was encountered in 71% of those undergoing 10mm unilateral recessions, versus 20% of those who had smaller recession doses. Limited ductions were mild, and exceeded -1 in 4 cases: 3 had had 10mm and 1 had had 9mm unilateral LR recession. Conclusions: Unilateral and bilateral LR recessions offer essentially equal success rates. Unilateral recessions are advised for angles up to 25∆, without exceeding 10mm. Figures Figure 1 INTRODUCTION The traditional surgical treatment for small to moderate angle horizontal strabismus is two-muscle surgery. One muscle surgery was, however, suggested due to several advantages, among which are shorter operating time and anesthesia exposure, limiting discomfort and complication risks to one eye with earlier recovery, and leaving other muscles unoperated in case reoperation is needed. The use of one muscle surgery, however, had been controversial because of concerns related to undercorrections or lateral incomitance. Nevertheless, several authors suggested that the induced lateral incomitance, although frequent, was rarely clinically significant. [ 1 – 3 ] The present study was conducted to compare unilateral versus bilateral lateral rectus (LR) recession for treatment of up to 35 prism diopters (∆) of exotropia (XT), aiming to compare the effect on ocular alignment and lateral incomitance, and to determine the more appropriate procedure for the various surgical target angles. MATERIALS AND METHODS Records of all patients with XT up to 35 ∆, operated upon by the first 2 authors, were included in a retrospective study to compare the effect of unilateral versus bilateral LR recession. Informed consent was obtained before surgery. The study and data collection conformed to all local laws, and were compliant with the principles of the Declaration of Helsinki. Approval of the study was obtained from the ophthalmic scientific committee and councils of the ophthalmic department and faculty of Medicine of Cairo University. Eligibility criteria included: exotropia, that is not fully corrected with glasses, with a surgical target angle of 14 to 35∆. Exclusion criteria included: previous strabismus surgery, paralytic or restrictive strabismus or less than 3 months of postoperative follow-up. Clinical evaluation on entry into the study comprised: history taking, corrected visual acuity measurement (whenever possible), ductions and versions, measurement of angle of deviation, cycloplegic refraction, and fundus examination. Spectacles were prescribed to within 1.0 diopter (D) of the patient's cycloplegic refraction and had to be worn for at least 4 weeks prior to inclusion in the study. Ductions and versions were evaluated on a scale of -1 to -4 for limited motility, 0 for normal motility, and + 1 to + 4 for overactions. Motor alignment was measured by the alternate cover and prism test at 6 meters in straight and vertical gazes, and at 0.33 meters in straight gaze. In uncooperative small children and in patients with poor vision, the modified Krimsky test was used instead. Measurements were recorded without and with correction. Lateral incomitance was defined as a difference in deviation between the primary position and lateral gaze of > 5 ∆ or any adduction or abduction deficit of -1 or more. Patients were divided into 2 groups according to the surgery performed. Group 1 included those who had undergone unilateral LR recession. Group 2 included those who had undergone bilateral LR recession. All patients underwent strabismus surgery under general anesthesia for a target angle equivalent to the average of the distant and near deviation with correction measured after 1-hour patch. Correction of any associated vertical muscle imbalance or oblique dysfunction was performed as indicated. The surgical dosage employed was based on Wright’s surgical tables with modifications (Table 1 ). [ 4 ] For unilateral LR recession, the amount of bilateral recession of double the patients’ deviation was used to recess one muscle. As an example, for a patient with XT 20∆, the deviation was doubled to 40∆. According to Wright’s surgical Tables, the amount of bilateral LR recession for 40∆ is 8mm; therefore, 8-mm unilateral LR recession was performed to treat the 20∆ exotropia. Recessions larger than 10 mm were avoided, so XT 35∆ received 10-mm recession as did the 30∆ exotropia. The surgical dosage in both groups was reduced by 0.5mm in cases of hypermetropia or tight lateral recti. Table 1 Surgical dosages for different surgical target angles. Angle of XT (∆) Bilateral LR recession (mm) Unilateral LR recession (mm) 14 4 7 16 4 7.5 18 5 8 20 5 8 25 6 9 30 7 10 35 7.5 10 Postoperative follow-up examinations were scheduled at 1 week, 6 weeks, 3 months, and 6 months, then every 6 months thereafter. Postoperative evaluation consisted of assessment of ocular alignment (in primary position for far and near and in up and down gaze positions) by prism and cover tests or the modified Krimsky test, assessment of ductions and versions, and sensory testing using the Titmus Stereo Test whenever possible. The study end-point was considered the last follow-up visit scheduled at least 3 months postoperatively. A successful motor outcome was defined as orthotropia, or a horizontal tropia of 10∆ or less at distance and near. Statistical analysis of the results was performed. Data were statistically described in terms of mean ± standard deviation (± SD), median and range, or frequencies (number of cases) and percentages when appropriate. Numerical data were tested for the normal assumption using Kolmogorov Smirnov test. Comparison of numerical variables between the study groups was done using Student t test for independent samples in comparing 2 groups of normally distributed data and Mann Whitney U test for independent samples for comparing not-normal data. Within group comparison of numerical variables was done using paired t test in comparing 2 groups when normally distributed and Wilcoxon signed rank test for paired (matched) samples when not normally distributed. For comparing categorical data, Chi-square (χ2) test was performed. Exact test was used instead when the expected frequency is less than 5. Paired categorical data were compared using McNemar test. Correlation between various variables was done using Pearson moment correlation equation for linear relation of normally distributed variables and Spearman rank correlation equation for non-normal variables/non-linear monotonic relation. Two-sided p values less than 0.05 was considered statistically significant. IBM SPSS (Statistical Package for the Social Science; IBM Corp, Armonk, NY, USA) release 22 for Microsoft Windows was used for all statistical analyses. RESULTS Records of 154 consecutive patients with XT 14 to 35∆, operated upon by the authors, and completed at least 3 months’ postoperative follow-up, were included in a retrospective study to compare the effect of unilateral versus bilateral LR recession. The baseline and surgical characteristics of groups 1 and 2 were compared in Table 2 . The 2 groups have shown harmonious baseline characteristics except for age, duration of XT, fixation preference and distant angle ( p < .05). Table 2 Baseline characteristics at entry into the study and surgical data. Group All patients (N = 154) Group 1 (n = 47) Group 2 (n = 107) Mean +/- SD (minimum - maximum) P values Group1 vs Group2 Age (years) 6.32+/-3.95 (1–30) 7.46+/-4.32 (3–25) 5.8+/-3.7 (1–30) .022* Age at onset (years) 3.31+/-2.67 (0–14) 2.86+/-3.33 (0–14) 3.47+/-2.4 (0-13.5) .333 Duration (years) 3.45+/-3.82 (0.1–30) 5.2+/-4.44 (1–25) 2.81+/-3.38 (0.1–30) .003* BCV (LogMAR) - OD - OS 0.15+/-0.2 (0–1) 0.15+/-0.19 (-0.2-1) 0.18+/-0.27 (0–1) 0.16+/-0.24 (-0.2-1) 0.14+/-0.16 (0–1) 0.14+/-0.16 (-0.2-0.8) .327 .719 Spherical equivalent (D) - OD - OS -0.49+/-1.82 (-10.75-3.75) -0.48+/-1.71 (-11.75-3.5) -0.68+/-2.61 (-10.75-3.5) -0.4+/-2.35 (-11.75-2.75) -0.41+/-1.35 (-3.25-3.75) -0.51+/-1.36 (-6-3.5) .229 .707 Distant angle of XT (∆) 1 24.14+/-5.04 (0–40) 22.51+/-6.08 (0–35) 24.8+/-4.42 (16–40) .020* Near angle of XT (∆) 1 23.06+/-6.55 (0–40) 23.27+/-6.79 (12–40) 22.97+/-6.48 (0–40) .696 Surgical target angle (∆) 24.25+/-5.02 (14–35) 23.19+/-5.58 (14–35) 24.72+/-4.71 (16–35) .110 Recession per muscle (mm) 6.66+/-1.49 (4.5–10) 8.6+/-0.95 (6–10) 5.81+/-0.63 (4.5–7.5) < .001* Total recession (mm) 10.66+/1.90 (6–16) 8.6+/-0.95 (6–10) 11.5+/-1.43 (6–15) < .001* Number (percent) P values Sex - Male - Female 52(33.8) 102(66.2) 19(40.4) 28(59.6) 33(30.8) 74(69.2) 0.358 Fixation preference - Equal/mild - Strong 122(83%) 25(17%) 22(55%) 18(45%) 100(93.5%) 7(6.5%) < .001* Lateral incomitance -Yes -No 21(15.7%) 113(84.3%) 6(14.3%) 36(85.7%) 15(16.3%) 77(83.7%) 1.000 1 =Distant & near angle with glasses if using glasses; SD = standard deviation; D = diopters; ∆=prism diopters. Data of early (1 week) and late follow-up (3-120 months) are shown in Table 3 . The success rate was almost equal in both groups. All failures in group 1 and most of those in group 2 were due to undercorrection. Overcorrection was recorded in only 3 cases in group 2. Limited ductions and lateral incomitance were significantly higher in group 1 than group 2 at 1 week and on the last follow-up visit. The Titmus Stereo Test was performed in 17 cases in group 1 (who all achieved fine stereopsis), and in 35 cases in group 2 (of whom 31 (86.6%) had fine and 4 (11.4% had gross stereopsis), p = .290. Table 3 Postoperative data. 1 week postoperative follow-up: Group All patients (N = 130) Group 1 (n = 30) Group 2 (n = 100) P values Group1 vs Group2 Ocular alignment (N,%) 1 - Orthotropia - Residual XT - Consecutive ET 67(51.5%) 19(14.6%) 44(33.8%) 18(60%) 7(23.3%) 5(16.7%) 49(49%) 12(12%) 39(39%) .057 Dcc (∆, mean+/-SD) 3.89+/-6.22 (0–35) 3.57+/-5.48 (0–18) 3.99+/-6.45 (0–35) .858 Ncc (∆, mean+/-SD) 2.21+/-4.60 (0–20) 2.55+/-5.63 (0–20) 2.09+/-4.24 (0–20) .566 Ductions LR1 (N,%) 0 -1 -2 -3 Mean+/-SD 90 (81.1%) 10 (9%) 7 (6.3%) 4 (3.6%) -0.32+/-0.75 10 (38.5%) 5 (19.2%) 7 (26.9%) 4 (15.4%) -1.19+/-1.13 80 (94.1%) 5 (5.9%) 0 (0%) 0 (0%) -0.06+/-0.24 < .001* Ductions LR2 (N,%) 0 -1 -2 Mean+/-SD - - 80 (95.2%) 3 (3.6%) 1 (1.2%) -0.06+/-0.28 - Lateral incomitance -Yes -No 21(18.6%) 92(81.4%) 16(61.5%) 10(38.5%) 5(5.7%) 82(94.3%) < .001* Last postoperative follow-up: Group All patients (N = 154) Group 1 (n = 47) Group 2 (n = 107) P values Group1 vs Group2 Duration (m, mean+/-SD) 26.7+/-24.88 (3-120) 13.99+/-15.59 (3–69) 32.3+/-26.17 (3-120) < .001* Ocular alignment (N,%) 1 - Orthotropia - Residual XT - Consecutive ET 91(59.1%) 51(33.1%) 12(7.8%) 33(70.2%) 13(27.7%) 1(2.1%) 58(54.2%) 38(35.5%) 11(10.3%) .102 Dcc (∆, mean+/-SD) 3.56+/-5.97 (0–30) 3.42+/-7 (0–30) 3.62+/-5.48 (0–20) .941 Ncc (∆, mean+/-SD) 3.57+/-7.55 (0–50) 3.96+/-8.56 (0–35) 3.39+/-7.06 (0–50) .610 Ductions LR1 (N,%) 0 -1 -2 Mean+/-SD 114 (88.4%) 11 (8.5%) 4 (3.1%) -0.15+/-0.44 31 (70.5%) 9 (20.5%) 4 (9.1%) -0.39+/-0.65 83 (97.6%) 2 (2.4%) 0 (0%) -0.02+/-0.15 < .001* Ductions LR2 (N,%) 0 -1 Mean+/-SD - - 85 (98.8%) 1 (1.2%) -0.01+/-0.11 - Lateral incomitance -Yes -No 15(11.5%) 115(88.5%) 13(29.5%) 31(70.5%) 2(2.3%) 84(97.7%) < .001* Motor outcome (N,%) 2 - Success - Failure 127(82.5%) 27(17.5%) 39(83%) 8(17%) 88(82.2%) 19(17.8%) .976 Motor outcome (N,%) 3 - Corrected - Undercorrected - Overcorrected 127(82.5%) 24(15.6%) 3(1.9%) 39(83%) 8(17%) 0(0%) 88(82.2%) 16(15%) 3(2.8%) .419 ET = Esotropia; XT = Exotropia; Dcc = Distance deviation with glasses; Ncc = Near deviation with glasses; LR = Lateral rectus; SD = standard deviation; m = months; ∆=prism diopters; 1 =ET or XT of any degree; 2 = Success = orthotropia or ET or XT up to 10PD, failure = ET or XT > 10PD; 3 =Corrected = orthotropia or ET or XT up to 10PD, undercorrected = residual XT > 10PD, overcorrected = consecutive ET > 10PD. There was a statistically significant correlation between the motor outcome and both the surgical target angle and the amount of recession in group 1 but not in group 2 (Table 4 ). Success rates were higher in group 1 than 2 for angles up to 25∆. For larger angles, bilateral surgery was more successful (Fig. 1 a). For all surgical target angles, lateral incomitance was more frequent in group 1 than 2 (Fig. 1 b). The rate of lateral incomiance was 71% after 10mm unilateral LR recession, but only 20% for smaller amounts of unilateral recessions. Most cases of lateral incomitance, however, showed limited ductions not exceeding − 1, with only 4 patients having − 2 limitations, on the final follow-up. Of these 4 patients, 3 had had 10-mm and 1 had had 9-mm unilateral LR recession. Table 4 Relation of the surgical outcome to the surgical target angle and amount of lateral rectus recession. Motor outcome Surgical target angle (∆) Recession per LR muscle (mm) Total recession for both LR muscles (mm) Group 1: Corrected (within 10∆ of orthotropia) 22.19+/-5.06 8.46+/-0.87 - Undercorrected (residual XT > 10∆) 27.67+/-5.94 9.22+/-1.12 - p value .008* .006* - Group 2: Corrected 24.85+/-4.77 5.85+/-0.65 11.55+/-1.5 Undercorrected 23+/-3.27 5.58+/-0.52 11.16+/-1.04 Overcorrected (consecutive ET > 10∆) 28.33+/-7.64 6.67+/-1.04 13.33+/-2.08 p value .208 .190 .229 Comparing angles of deviation on entry versus 1 week postoperatively, there was a significant decrease of deviation in groups 1 and 2 ( p < .001). On comparing postoperative angles of deviation at 1 week versus the last follow-up, an insignificant decrease in distant angles and an insignificant increase in near angles of deviation were noted in both groups ( p > .05). Comparing the incidence of lateral incomitance documented at entry into the study versus 1 week postoperatively and the last follow-up, a significant increase was noted in group 1 ( p = .001 and .022, respectively). Comparing those in group 2, it was noted that lateral incomitance was less frequent at 1 week ( p = .607) and the last follow-up ( p = .001) than on entry into the study. Lateral incomitance decreased significantly in both groups on the last follow-up versus 1 week postoperatively ( p = .001). Lateral rectus ductions were less limited on the final follow-up, as compared to the first postoperative week, by a mean of 0.72+/-0.84 in group 1 ( p < .001) and by a mean of 0.09+/-0.37 in one LR and 0.06+/-0.34 in the other LR in group 2 ( p = .057 and .159, respectively). These results suggest essentially equal success rates for unilateral and bilateral surgery for exotropia. Success rates are superior after unilateral surgery for angles up to 25∆. For larger angles, bilateral surgery is better. There was, however, persistently higher frequency of lateral incomitance after unilateral surgery for all surgical target angles. The latter is most pronounced after 10mm unilateral LR recession. DISCUSSION The goal of strabismus surgery is to align the eyes, thereby preserving stereoacuity and visual acuity. The traditional treatment for both exotropia and esotropia (ET) is two-muscle strabismus surgery as either bilateral rectus muscle recession or combined unilateral rectus recession and antagonist rectus resection. One-muscle recession has various theoretical advantages over two-muscle surgery, namely limiting surgery to one eye, leaving other muscles untouched if repeat surgery is needed, shorter operative time with less anesthetic exposure, and less surgical complications. [ 1 , 5 ] However, this procedure is controversial because of concerns regarding undercorrection and/or induced incomitance. [ 1 , 5 – 31 ] Several studies have shown that one-muscle surgery provides promising outcomes, especially in small to moderate horizontal deviations, with success rates ranging from 73–100%. [ 5 – 7 , 9 , 10 , 12 , 14 , 16 – 20 ] Conversely, other studies reported a < 60% success rate, [ 29 – 31 ] one of which reported only 36% success, with 63% under- and 1% overcorrection. [ 30 ] Inconsistent surgical outcomes between studies were likely caused by different inclusion criteria, surgical dosages, definition of success, follow-up time, demographic backgrounds, and variable surgeon technique and experience. [ 5 ] The success rate obtained in the present study after single-muscle surgery was 83%, and was slightly higher than that obtained in the two-muscle group. In agreement with previous studies, [ 6 – 31 ] in the present study, all failures in the single-muscle group were due to undercorrections, and lateral incomitance was significantly higher than after bilateral surgery. Since one muscle surgery has been studied in only small to moderate angle strabismus and the majority of unsuccessful cases were undercorrections, [ 6 – 31 ] it may not be effective against large angle strabismus. A dose-response relationship study suggested that one muscle recession can be used in XT or ET < 30∆. [ 14 ] In agreement, the present study included XT with angles 14 to 35∆, to avoid the need for recessions larger than 10 mm, which could be more demanding due to difficult exposure and the close proximity to the site of insertion of the inferior oblique muscle, as well as to attempt to minimize the degree of postoperative lateral incomitance. Moreover, the 3 cases of 35∆ XT were treated by only 10-mm recession (the same as the 30∆-XT), assuming that the remaining 5∆ can be easily fused in patients who have a potential for fusion. The surgical dosages for unilateral LR recession differed among different studies. [ 5 ] Feretis et al. [ 32 ] used large unilateral LR recessions of 11.5 mm to 12 mm for small angle exodeviations of 15–16∆ in 10 patients. Although all cases were initially overcorrected, they all achieved orthophoria by 4 weeks. Nelson et al. [ 9 ] reported a 94% success rate in 55 patients with XT 15–20∆ receiving unilateral LR recessions of 7, 7.5, and 8 mm, respectively. Later, Wang and Nelson [ 19 ] matched specific magnitudes of unilateral LR recession (7 mm to 10 mm) to specific magnitudes of XT (15 to 35 ∆) and reported a success rate of 76% and a significant correlation between the preoperative angle of deviation and final success. Almahmoudi et al. [ 20 ] performed 6 to 11 mm of unilateral LR recession for 12 to 30∆ of XT in 30 patients, with initial success in 73.3% that dropped to 63.3% on the last follow-up due to late undercorrection. Unlike the study of Wang and Nelson, [ 19 ] the authors reported no significant correlation of success rate to preoperative angle. [ 20 ] Lekskul et al. performed unilateral LR recessions, in 25 patients, of 8, 9 and 10 mm for 15, 20 and 25 ∆ of XT, respectively, and reported a success rate of 76%, with no significant differences between success rates recorded for the different amounts of preoperative deviations. [ 5 ] In the present study, the surgical doses were essentially based on Wright’s surgical tables, with modifications [ 4 ] (Table 1 ). A success rate of 83% was recorded in the current study after unilateral LR recession, and there was a statistically significant correlation between the motor outcome and both the surgical target angle and the amount of recession in group 1 but not in group 2. The previous discussion reflects the variability in surgical dosages among different studies. These results emphasize the assumption that it is not merely the surgical dosage that affects the final results, but, more importantly, the patient’s response to surgery and the ability to regain fusion. One of the major advantages of unilateral LR recession is the small percentage of overcorrection. Consecutive ET after strabismus surgery may lead to intolerable diplopia and loss of stereopsis, requiring further intervention. Several authors also reported no overcorrection after unilateral surgery, [ 5 ] or at least noted overcorrection only in the early postoperative period, which disappeared over time. [ 6 , 7 , 9 , 13 , 17 , 18 , 26 – 29 ] Consecutive ET following unilateral LR recession was reported in some studies at a low rate ranging from 1–10% of the patients. [ 9 , 12 , 14 , 16 , 19 , 30 , 31 ] In the current study, a single case showed a consecutive ET exceeding 10∆ at 1 week, but achieved orthotropia on the last follow-up. On the other hand, 3 cases in the bilateral surgery group had persistent consecutive ET exceeding 10∆, which reflects the advantage of unilateral surgery. One complication after unilateral LR recession is lateral incomitance. Although several studies reported no incomitance after unilateral recession, [ 7 , 13 , 16 – 18 , 26 , 27 , 30 ] yet others did. [ 5 , 28 , 29 ] The low incidence of lateral incomitance after unilateral LR recession was attributed to the long arc of contact of the LR muscle and the position of functional equator that is posterior to the anatomical equator. [ 7 ] Two studies reported lateral incomitance in some patients undergoing unilateral LR recession exceeding 9 mm, but this complication was noted only in the early postoperative period, decreased with time, and disappeared 2–4 months after surgery. [ 28 , 29 ] One study, however, reported lateral incomitance in 32% in the early postoperative period, that persisted till at least 3 months after surgery. The authors, however, stated that abduction limitation was mild in all cases, and was functionally and cosmetically acceptable. One study recommended that unilateral LR recession should not exceed 9 mm to lower the risk of lateral incomitance. [ 12 ] On the other hand, another study reported no lateral incomitance with unilateral LR recessions up to 10 mm. [ 19 ] In the present study, unilateral LR recessions were performed up to 10 mm. Lateral incomitance was recorded at a rate of 61.5% at one week, which went down to 29.5% on the final follow-up. Most cases, however, showed limited ductions not exceeding − 1, with only 4 patients having − 2 limitations, on the final follow-up. Of these 4 patients, 3 had had 10-mm LR recession and 1 had had 9-mm recession. Moreover, 5/7 patients (71%) who had 10-mm unilateral LR recession developed lateral incomitance, while only 4/16 (25%) of those who received unilateral 9-mm recession showed incomitance. The overall incidence of lateral incomitance for recessions below 10mm was 8/40 (20%). This supports the previous recommendation that unilateral LR recession should not exceed 9 mm. [ 12 ] In conclusion, unilateral LR recession offers a better alternative to bilateral LR recession for correction of XT up to 25∆, without exceeding 9 mm of recession. It is not advisable for larger angles as there is risk of undercorrection and persistent lateral incomitance. Declarations Conflict of interest: The authors report no conflict of interest. Author Contribution RK.Idea of manuscript, examined and operated on patients, collected literature, analyzed data, wrote the manuscript.RE.Filled in excel sheet.REM.Filled in excel sheet.HE.Examined and operated on patients, revised the manuscript. References Wang L, Nelson LB. One-muscle strabismus surgery. Curr Opin Ophthalmol. 2010;21(5):335–40. Gurland J, Vagge A, Nelson LB. One-muscle strabismus surgery: a review. J Pediatr Ophthalmol Strabismus. 2018;55(5):288–92. Kimberly MS, Areaux RG. 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Unilateral medial rectus recession for small-angle esotropia. Arch Ophthalmol. 1976;94(5):780–781. Spierer O, Spierer A. Unilateral lateral rectus recession is an effective surgery for intermittent exotropia in young children. BMC Ophthalmol. 2021;21(1):10. Lyu IJ, Park KA, Oh SY. Long-term surgical outcomes and factors for recurrence after unilateral lateral rectus muscle recession. Br J Ophthalmol. 2016;100(10):1433–1436. Spierer A, Ben-Simon GJ. Unilateral and bilateral lateral rectus recession in exotropia. Ophthalmic Surg Lasers Imaging. 2005;36 (2):114–117. Wang L, Nelson LB. Outcome study of unilateral lateral rectus recession for small to moderate angle intermittent exotropia in children. J Pediatr Ophthalmol Strabismus. 2010;47(4):242–247. Almahmoudi FH, Al Shamrani M, Khan AM. The use of one muscle recession for horizontal strabismus. Saudi J Ophthalmol. 2018;32 (3):200–203. Cogen MS, Roberts BW. Graded unilateral supramaximal medial rectus recession for moderate angle esotropia. Binocul Vis Strabismus Q. 2006;21(3):147–153. Wang L, Wang X. Comparison between graded unilateral and bilateral medial rectus recession for esotropia. Br J Ophthalmol. 2012;96 (4):540–543. Grin TR, Nelson LB. Large unilateral medial rectus recession for the treatment of esotropia. Br J Ophthalmol. 1987;71 (5):377–379. Stack RR, Burley CD, Bedggood A, Elder MJ. Unilateral versus bilateral medial rectus recession. J AAPOS. 2003;7(4):263–267. Wang L, Nelson LB. Outcome study of graded unilateral medial rectus recession for small to moderate angle esotropia. J Pediatr Ophthalmol Strabismus. 2011;48(1):20–24. Oh SY, Choi HY, Lee JY, Oh SY. Surgical outcomes related to degree of unilateral lateral rectus muscle recession in intermittent exotropia of 20 prism diopters. Jpn J Ophthalmol. 2020;64(6):621–627. Spierer O, Spierer A, Glovinsky J, Ben-Simon GJ. Moderate- angle exotropia: a comparison of unilateral and bilateral rectus muscle recession. Ophthalmic Surg Lasers Imaging. 2010;41(3):355–359. Kim HJ, Kim D, Choi DG. Long-term outcomes of unilateral lateral rectus recession versus recess-resect for intermittent exotropia of 20–25 prism diopters. BMC Ophthalmol. 2014;14:46. Suh SY, Choi J, Kim SJ. Comparative study of lateral rectus recession versus recession-resection in unilateral surgery for intermittent exotropia. J AAPOS. 2015;19(6):507–511. Yang HK, Kim MJ, Hwang JM. Predictive factors affecting long-term outcome of unilateral lateral rectus recession. PLoS One. 2015;10(9): e0137687. Kim H, Yang HK, Hwang JM. Comparison of long-term surgical outcomes between unilateral recession and unilateral recession-resection in small-angle exotropia. Am J Ophthalmol. 2016;166:141–148. Feretis D, Mela E, Vasilopoulos G. Excessive single lateral rectus muscle recession in the treatment of intermittent exotropia. J Pediatr Ophthalmol Strabismus 1990;27:315–6. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 17 Oct, 2024 Read the published version in International Ophthalmology → Version 1 posted Editorial decision: Revision requested 16 Aug, 2024 Reviews received at journal 07 Aug, 2024 Reviewers agreed at journal 06 Aug, 2024 Reviewers invited by journal 30 Jun, 2024 Editor assigned by journal 19 Jun, 2024 Submission checks completed at journal 19 Jun, 2024 First submitted to journal 18 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4598867","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":321804698,"identity":"94315be0-368d-4b24-b25f-963eefe5bbf9","order_by":0,"name":"Rehab Rashad Kassem","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9ElEQVRIiWNgGAWjYFACHgZmBoYECPtjA4hkbDxAtBbGmQ0MEkCqgXgtzLxgLQwMeLWYt/ce/Fy4J01evv/w0c22O2zqdNsPA22psYnGpUXmzLlk6RnPcgw33EhLu517Jk3C7EwiUMuxtNwGHFokJHIMpHkOVDBukOAxu53bdljC7ABQC2PDYdxa5N8Y/wZqsZ/ff/7bbUuQlvMPCWgBGg60JQdocg7bbUaQlhuEbOHJMbOecSAtGegXs5u9bWmS224AbUnA5xf2M8a3Cw4k287vP/zsxs82G36z8+kPH3yoscGpBQdIIE35KBgFo2AUjAI0AADAG2RMxOOjFgAAAABJRU5ErkJggg==","orcid":"","institution":"Kasr Alainy hospital","correspondingAuthor":true,"prefix":"","firstName":"Rehab","middleName":"Rashad","lastName":"Kassem","suffix":""},{"id":321804699,"identity":"790fd37d-9836-46de-bf58-1313b96e28e3","order_by":1,"name":"Rokaya Emad Radwan","email":"","orcid":"","institution":"Kasr Alainy hospital","correspondingAuthor":false,"prefix":"","firstName":"Rokaya","middleName":"Emad","lastName":"Radwan","suffix":""},{"id":321804700,"identity":"3a304452-176a-4d13-bea2-6139c8c0dce6","order_by":2,"name":"Randa El-Mofty","email":"","orcid":"","institution":"Kasr Alainy hospital","correspondingAuthor":false,"prefix":"","firstName":"Randa","middleName":"","lastName":"El-Mofty","suffix":""},{"id":321804701,"identity":"b0e5ed2e-10eb-4c2c-9e27-8c5c8bc56c9c","order_by":3,"name":"Hala Mostafa Elhilali","email":"","orcid":"","institution":"Kasr Alainy hospital","correspondingAuthor":false,"prefix":"","firstName":"Hala","middleName":"Mostafa","lastName":"Elhilali","suffix":""}],"badges":[],"createdAt":"2024-06-18 09:21:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4598867/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4598867/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10792-024-03324-1","type":"published","date":"2024-10-17T15:57:45+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60594239,"identity":"d8c39d99-bd20-4bd0-a05a-b75c01d8791c","added_by":"auto","created_at":"2024-07-18 15:21:35","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":80110,"visible":true,"origin":"","legend":"\u003cp\u003eBar charts highlighting success rates (a) and risk of lateral incomitance (b) for different surgical target angles.\u003c/p\u003e\n\u003cp\u003eSTAs= surgical target angles; PD=prism diopters.\u003c/p\u003e","description":"","filename":"Fig1small.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4598867/v1/bd6a5790e6be053484f4cd48.jpg"},{"id":67149739,"identity":"5c3131e5-bc84-4147-8af1-14a41b6d8416","added_by":"auto","created_at":"2024-10-21 16:13:59","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":660316,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4598867/v1/6d858f00-0b79-4907-8868-8eee8f6a0513.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe traditional surgical treatment for small to moderate angle horizontal strabismus is two-muscle surgery. One muscle surgery was, however, suggested due to several advantages, among which are shorter operating time and anesthesia exposure, limiting discomfort and complication risks to one eye with earlier recovery, and leaving other muscles unoperated in case reoperation is needed. The use of one muscle surgery, however, had been controversial because of concerns related to undercorrections or lateral incomitance. Nevertheless, several authors suggested that the induced lateral incomitance, although frequent, was rarely clinically significant.\u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe present study was conducted to compare unilateral versus bilateral lateral rectus (LR) recession for treatment of up to 35 prism diopters (∆) of exotropia (XT), aiming to compare the effect on ocular alignment and lateral incomitance, and to determine the more appropriate procedure for the various surgical target angles.\u003c/p\u003e"},{"header":"MATERIALS AND METHODS","content":"\u003cp\u003eRecords of all patients with XT up to 35 ∆, operated upon by the first 2 authors, were included in a retrospective study to compare the effect of unilateral versus bilateral LR recession. Informed consent was obtained before surgery. The study and data collection conformed to all local laws, and were compliant with the principles of the Declaration of Helsinki. Approval of the study was obtained from the ophthalmic scientific committee and councils of the ophthalmic department and faculty of Medicine of Cairo University.\u003c/p\u003e \u003cp\u003eEligibility criteria included: exotropia, that is not fully corrected with glasses, with a surgical target angle of 14 to 35∆. Exclusion criteria included: previous strabismus surgery, paralytic or restrictive strabismus or less than 3 months of postoperative follow-up.\u003c/p\u003e \u003cp\u003eClinical evaluation on entry into the study comprised: history taking, corrected visual acuity measurement (whenever possible), ductions and versions, measurement of angle of deviation, cycloplegic refraction, and fundus examination. Spectacles were prescribed to within 1.0 diopter (D) of the patient's cycloplegic refraction and had to be worn for at least 4 weeks prior to inclusion in the study. Ductions and versions were evaluated on a scale of -1 to -4 for limited motility, 0 for normal motility, and +\u0026thinsp;1 to +\u0026thinsp;4 for overactions. Motor alignment was measured by the alternate cover and prism test at 6 meters in straight and vertical gazes, and at 0.33 meters in straight gaze. In uncooperative small children and in patients with poor vision, the modified Krimsky test was used instead. Measurements were recorded without and with correction. Lateral incomitance was defined as a difference in deviation between the primary position and lateral gaze of \u0026gt;\u0026thinsp;5 ∆ or any adduction or abduction deficit of -1 or more.\u003c/p\u003e \u003cp\u003ePatients were divided into 2 groups according to the surgery performed. Group 1 included those who had undergone unilateral LR recession. Group 2 included those who had undergone bilateral LR recession.\u003c/p\u003e \u003cp\u003eAll patients underwent strabismus surgery under general anesthesia for a target angle equivalent to the average of the distant and near deviation with correction measured after 1-hour patch. Correction of any associated vertical muscle imbalance or oblique dysfunction was performed as indicated.\u003c/p\u003e \u003cp\u003eThe surgical dosage employed was based on Wright\u0026rsquo;s surgical tables with modifications (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e For unilateral LR recession, the amount of bilateral recession of double the patients\u0026rsquo; deviation was used to recess one muscle. As an example, for a patient with XT 20∆, the deviation was doubled to 40∆. According to Wright\u0026rsquo;s surgical Tables, the amount of bilateral LR recession for 40∆ is 8mm; therefore, 8-mm unilateral LR recession was performed to treat the 20∆ exotropia. Recessions larger than 10 mm were avoided, so XT 35∆ received 10-mm recession as did the 30∆ exotropia. The surgical dosage in both groups was reduced by 0.5mm in cases of hypermetropia or tight lateral recti.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSurgical dosages for different surgical target angles.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAngle of XT (∆)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBilateral LR recession (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eUnilateral LR recession (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003ePostoperative follow-up examinations were scheduled at 1 week, 6 weeks, 3 months, and 6 months, then every 6 months thereafter. Postoperative evaluation consisted of assessment of ocular alignment (in primary position for far and near and in up and down gaze positions) by prism and cover tests or the modified Krimsky test, assessment of ductions and versions, and sensory testing using the Titmus Stereo Test whenever possible.\u003c/p\u003e \u003cp\u003eThe study end-point was considered the last follow-up visit scheduled at least 3 months postoperatively. A successful motor outcome was defined as orthotropia, or a horizontal tropia of 10∆ or less at distance and near.\u003c/p\u003e \u003cp\u003eStatistical analysis of the results was performed. Data were statistically described in terms of mean \u0026plusmn; standard deviation (\u0026plusmn; SD), median and range, or frequencies (number of cases) and percentages when appropriate. Numerical data were tested for the normal assumption using Kolmogorov Smirnov test. Comparison of numerical variables between the study groups was done using Student t test for independent samples in comparing 2 groups of normally distributed data and Mann Whitney U test for independent samples for comparing not-normal data. Within group comparison of numerical variables was done using paired t test in comparing 2 groups when normally distributed and Wilcoxon signed rank test for paired (matched) samples when not normally distributed. For comparing categorical data, Chi-square (χ2) test was performed. Exact test was used instead when the expected frequency is less than 5. Paired categorical data were compared using McNemar test. Correlation between various variables was done using Pearson moment correlation equation for linear relation of normally distributed variables and Spearman rank correlation equation for non-normal variables/non-linear monotonic relation. Two-sided p values less than 0.05 was considered statistically significant. IBM SPSS (Statistical Package for the Social Science; IBM Corp, Armonk, NY, USA) release 22 for Microsoft Windows was used for all statistical analyses.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eRecords of 154 consecutive patients with XT 14 to 35∆, operated upon by the authors, and completed at least 3 months\u0026rsquo; postoperative follow-up, were included in a retrospective study to compare the effect of unilateral versus bilateral LR recession. The baseline and surgical characteristics of groups 1 and 2 were compared in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The 2 groups have shown harmonious baseline characteristics except for age, duration of XT, fixation preference and distant angle (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.05).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBaseline characteristics at entry into the study and surgical data.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll patients (N\u0026thinsp;=\u0026thinsp;154)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup 1 (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup 2 (n\u0026thinsp;=\u0026thinsp;107)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eMean +/- SD (minimum - maximum)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e values Group1 vs Group2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.32+/-3.95\u003c/p\u003e \u003cp\u003e(1\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.46+/-4.32\u003c/p\u003e \u003cp\u003e(3\u0026ndash;25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.8+/-3.7\u003c/p\u003e \u003cp\u003e(1\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.022*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at onset (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.31+/-2.67\u003c/p\u003e \u003cp\u003e(0\u0026ndash;14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.86+/-3.33\u003c/p\u003e \u003cp\u003e(0\u0026ndash;14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.47+/-2.4\u003c/p\u003e \u003cp\u003e(0-13.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.333\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuration (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.45+/-3.82\u003c/p\u003e \u003cp\u003e(0.1\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.2+/-4.44\u003c/p\u003e \u003cp\u003e(1\u0026ndash;25)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.81+/-3.38\u003c/p\u003e \u003cp\u003e(0.1\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.003*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBCV (LogMAR)\u003c/p\u003e \u003cp\u003e- OD\u003c/p\u003e \u003cp\u003e- OS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.15+/-0.2 (0\u0026ndash;1)\u003c/p\u003e \u003cp\u003e0.15+/-0.19 (-0.2-1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.18+/-0.27 (0\u0026ndash;1)\u003c/p\u003e \u003cp\u003e0.16+/-0.24 (-0.2-1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.14+/-0.16 (0\u0026ndash;1)\u003c/p\u003e \u003cp\u003e0.14+/-0.16 (-0.2-0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.327\u003c/p\u003e \u003cp\u003e.719\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSpherical equivalent (D)\u003c/p\u003e \u003cp\u003e- OD\u003c/p\u003e \u003cp\u003e- OS\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.49+/-1.82\u003c/p\u003e \u003cp\u003e(-10.75-3.75)\u003c/p\u003e\u003cp\u003e-0.48+/-1.71\u003c/p\u003e \u003cp\u003e(-11.75-3.5)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.68+/-2.61\u003c/p\u003e \u003cp\u003e(-10.75-3.5)\u003c/p\u003e\u003cp\u003e-0.4+/-2.35\u003c/p\u003e \u003cp\u003e(-11.75-2.75)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-0.41+/-1.35\u003c/p\u003e \u003cp\u003e(-3.25-3.75)\u003c/p\u003e\u003cp\u003e-0.51+/-1.36\u003c/p\u003e \u003cp\u003e(-6-3.5)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.229\u003c/p\u003e \u003cp\u003e.707\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDistant angle of XT (∆)\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.14+/-5.04\u003c/p\u003e \u003cp\u003e(0\u0026ndash;40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.51+/-6.08\u003c/p\u003e \u003cp\u003e(0\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24.8+/-4.42\u003c/p\u003e \u003cp\u003e(16\u0026ndash;40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.020*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNear angle of XT (∆)\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23.06+/-6.55\u003c/p\u003e \u003cp\u003e(0\u0026ndash;40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.27+/-6.79\u003c/p\u003e \u003cp\u003e(12\u0026ndash;40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22.97+/-6.48\u003c/p\u003e \u003cp\u003e(0\u0026ndash;40)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.696\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSurgical target angle (∆)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.25+/-5.02\u003c/p\u003e \u003cp\u003e(14\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.19+/-5.58\u003c/p\u003e \u003cp\u003e(14\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e24.72+/-4.71\u003c/p\u003e \u003cp\u003e(16\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.110\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRecession per muscle (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.66+/-1.49\u003c/p\u003e \u003cp\u003e(4.5\u0026ndash;10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.6+/-0.95\u003c/p\u003e \u003cp\u003e(6\u0026ndash;10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.81+/-0.63\u003c/p\u003e \u003cp\u003e(4.5\u0026ndash;7.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal recession (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.66+/1.90\u003c/p\u003e \u003cp\u003e(6\u0026ndash;16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.6+/-0.95\u003c/p\u003e \u003cp\u003e(6\u0026ndash;10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.5+/-1.43\u003c/p\u003e \u003cp\u003e(6\u0026ndash;15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eNumber (percent)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e values\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003cp\u003e- Male\u003c/p\u003e \u003cp\u003e- Female\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e52(33.8)\u003c/p\u003e \u003cp\u003e102(66.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19(40.4)\u003c/p\u003e \u003cp\u003e28(59.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33(30.8)\u003c/p\u003e \u003cp\u003e74(69.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.358\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFixation preference\u003c/p\u003e \u003cp\u003e- Equal/mild\u003c/p\u003e \u003cp\u003e- Strong\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e122(83%)\u003c/p\u003e \u003cp\u003e25(17%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22(55%)\u003c/p\u003e \u003cp\u003e18(45%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100(93.5%)\u003c/p\u003e \u003cp\u003e7(6.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLateral incomitance\u003c/p\u003e \u003cp\u003e-Yes\u003c/p\u003e \u003cp\u003e-No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21(15.7%)\u003c/p\u003e \u003cp\u003e113(84.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6(14.3%)\u003c/p\u003e \u003cp\u003e36(85.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e15(16.3%)\u003c/p\u003e \u003cp\u003e77(83.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e\u003csup\u003e1\u003c/sup\u003e=Distant \u0026amp; near angle with glasses if using glasses; SD\u0026thinsp;=\u0026thinsp;standard deviation; D\u0026thinsp;=\u0026thinsp;diopters; ∆=prism diopters.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eData of early (1 week) and late follow-up (3-120 months) are shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The success rate was almost equal in both groups. All failures in group 1 and most of those in group 2 were due to undercorrection. Overcorrection was recorded in only 3 cases in group 2. Limited ductions and lateral incomitance were significantly higher in group 1 than group 2 at 1 week and on the last follow-up visit. The Titmus Stereo Test was performed in 17 cases in group 1 (who all achieved fine stereopsis), and in 35 cases in group 2 (of whom 31 (86.6%) had fine and 4 (11.4% had gross stereopsis), \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.290.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePostoperative data.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003e1 week postoperative follow-up:\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll patients (N\u0026thinsp;=\u0026thinsp;130)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup 1 (n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup 2 (n\u0026thinsp;=\u0026thinsp;100)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e values Group1 vs Group2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOcular alignment (N,%)\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e- Orthotropia\u003c/p\u003e \u003cp\u003e- Residual XT\u003c/p\u003e \u003cp\u003e- Consecutive ET\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67(51.5%)\u003c/p\u003e \u003cp\u003e19(14.6%)\u003c/p\u003e \u003cp\u003e44(33.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18(60%)\u003c/p\u003e \u003cp\u003e7(23.3%)\u003c/p\u003e \u003cp\u003e5(16.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e49(49%)\u003c/p\u003e \u003cp\u003e12(12%)\u003c/p\u003e \u003cp\u003e39(39%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.057\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDcc (∆, mean+/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.89+/-6.22\u003c/p\u003e \u003cp\u003e(0\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.57+/-5.48\u003c/p\u003e \u003cp\u003e(0\u0026ndash;18)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.99+/-6.45\u003c/p\u003e \u003cp\u003e(0\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.858\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNcc (∆, mean+/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.21+/-4.60\u003c/p\u003e \u003cp\u003e(0\u0026ndash;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.55+/-5.63\u003c/p\u003e \u003cp\u003e(0\u0026ndash;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.09+/-4.24\u003c/p\u003e \u003cp\u003e(0\u0026ndash;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.566\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuctions LR1\u003c/p\u003e \u003cp\u003e(N,%)\u003c/p\u003e \u003cp\u003e0\u003c/p\u003e \u003cp\u003e-1\u003c/p\u003e \u003cp\u003e-2\u003c/p\u003e\u003cp\u003e-3\u003c/p\u003e\u003cp\u003eMean+/-SD\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e90 (81.1%)\u003c/p\u003e \u003cp\u003e10 (9%)\u003c/p\u003e \u003cp\u003e7 (6.3%)\u003c/p\u003e \u003cp\u003e4 (3.6%)\u003c/p\u003e \u003cp\u003e-0.32+/-0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (38.5%)\u003c/p\u003e \u003cp\u003e5 (19.2%)\u003c/p\u003e \u003cp\u003e7 (26.9%)\u003c/p\u003e \u003cp\u003e4 (15.4%)\u003c/p\u003e \u003cp\u003e-1.19+/-1.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80 (94.1%)\u003c/p\u003e \u003cp\u003e5 (5.9%)\u003c/p\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003cp\u003e-0.06+/-0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuctions LR2\u003c/p\u003e \u003cp\u003e(N,%)\u003c/p\u003e \u003cp\u003e0\u003c/p\u003e \u003cp\u003e-1\u003c/p\u003e \u003cp\u003e-2\u003c/p\u003e \u003cp\u003eMean+/-SD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80 (95.2%)\u003c/p\u003e \u003cp\u003e3 (3.6%)\u003c/p\u003e \u003cp\u003e1 (1.2%)\u003c/p\u003e \u003cp\u003e-0.06+/-0.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLateral incomitance\u003c/p\u003e \u003cp\u003e-Yes\u003c/p\u003e \u003cp\u003e-No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21(18.6%)\u003c/p\u003e \u003cp\u003e92(81.4%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e16(61.5%)\u003c/p\u003e \u003cp\u003e10(38.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5(5.7%)\u003c/p\u003e \u003cp\u003e82(94.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eLast postoperative follow-up:\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGroup\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAll patients (N\u0026thinsp;=\u0026thinsp;154)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGroup 1 (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eGroup 2 (n\u0026thinsp;=\u0026thinsp;107)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e values Group1 vs Group2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuration (m, mean+/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.7+/-24.88\u003c/p\u003e \u003cp\u003e(3-120)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13.99+/-15.59\u003c/p\u003e \u003cp\u003e(3\u0026ndash;69)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32.3+/-26.17\u003c/p\u003e \u003cp\u003e(3-120)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOcular alignment (N,%)\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e- Orthotropia\u003c/p\u003e \u003cp\u003e- Residual XT\u003c/p\u003e \u003cp\u003e- Consecutive ET\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e91(59.1%)\u003c/p\u003e \u003cp\u003e51(33.1%)\u003c/p\u003e \u003cp\u003e12(7.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33(70.2%)\u003c/p\u003e \u003cp\u003e13(27.7%)\u003c/p\u003e \u003cp\u003e1(2.1%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e58(54.2%)\u003c/p\u003e \u003cp\u003e38(35.5%)\u003c/p\u003e \u003cp\u003e11(10.3%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.102\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDcc (∆, mean+/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.56+/-5.97\u003c/p\u003e \u003cp\u003e(0\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.42+/-7\u003c/p\u003e \u003cp\u003e(0\u0026ndash;30)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.62+/-5.48\u003c/p\u003e \u003cp\u003e(0\u0026ndash;20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.941\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNcc (∆, mean+/-SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.57+/-7.55\u003c/p\u003e \u003cp\u003e(0\u0026ndash;50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.96+/-8.56\u003c/p\u003e \u003cp\u003e(0\u0026ndash;35)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.39+/-7.06\u003c/p\u003e \u003cp\u003e(0\u0026ndash;50)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.610\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuctions LR1\u003c/p\u003e \u003cp\u003e(N,%)\u003c/p\u003e \u003cp\u003e0\u003c/p\u003e \u003cp\u003e-1\u003c/p\u003e \u003cp\u003e-2\u003c/p\u003e\u003cp\u003eMean+/-SD\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e114 (88.4%)\u003c/p\u003e \u003cp\u003e11 (8.5%)\u003c/p\u003e \u003cp\u003e4 (3.1%)\u003c/p\u003e \u003cp\u003e-0.15+/-0.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31 (70.5%)\u003c/p\u003e \u003cp\u003e9 (20.5%)\u003c/p\u003e \u003cp\u003e4 (9.1%)\u003c/p\u003e \u003cp\u003e-0.39+/-0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e83 (97.6%)\u003c/p\u003e \u003cp\u003e2 (2.4%)\u003c/p\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003cp\u003e-0.02+/-0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuctions LR2\u003c/p\u003e \u003cp\u003e(N,%)\u003c/p\u003e \u003cp\u003e0\u003c/p\u003e \u003cp\u003e-1\u003c/p\u003e \u003cp\u003eMean+/-SD\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e85 (98.8%)\u003c/p\u003e \u003cp\u003e1 (1.2%)\u003c/p\u003e \u003cp\u003e-0.01+/-0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLateral incomitance\u003c/p\u003e \u003cp\u003e-Yes\u003c/p\u003e \u003cp\u003e-No\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15(11.5%)\u003c/p\u003e \u003cp\u003e115(88.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13(29.5%)\u003c/p\u003e \u003cp\u003e31(70.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2(2.3%)\u003c/p\u003e \u003cp\u003e84(97.7%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMotor outcome (N,%)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e- Success\u003c/p\u003e \u003cp\u003e- Failure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e127(82.5%)\u003c/p\u003e \u003cp\u003e27(17.5%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39(83%)\u003c/p\u003e \u003cp\u003e8(17%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88(82.2%)\u003c/p\u003e \u003cp\u003e19(17.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.976\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMotor outcome (N,%)\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003cp\u003e- Corrected\u003c/p\u003e \u003cp\u003e- Undercorrected\u003c/p\u003e \u003cp\u003e- Overcorrected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e127(82.5%)\u003c/p\u003e \u003cp\u003e24(15.6%)\u003c/p\u003e \u003cp\u003e3(1.9%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39(83%)\u003c/p\u003e \u003cp\u003e8(17%)\u003c/p\u003e \u003cp\u003e0(0%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88(82.2%)\u003c/p\u003e \u003cp\u003e16(15%)\u003c/p\u003e \u003cp\u003e3(2.8%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e.419\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eET\u0026thinsp;=\u0026thinsp;Esotropia; XT\u0026thinsp;=\u0026thinsp;Exotropia; Dcc\u0026thinsp;=\u0026thinsp;Distance deviation with glasses; Ncc\u0026thinsp;=\u0026thinsp;Near deviation with glasses; LR\u0026thinsp;=\u0026thinsp;Lateral rectus; SD\u0026thinsp;=\u0026thinsp;standard deviation; m\u0026thinsp;=\u0026thinsp;months; ∆=prism diopters; \u003csup\u003e1\u003c/sup\u003e=ET or XT of any degree; \u003csup\u003e2\u003c/sup\u003e= Success\u0026thinsp;=\u0026thinsp;orthotropia or ET or XT up to 10PD, failure\u0026thinsp;=\u0026thinsp;ET or XT\u0026thinsp;\u0026gt;\u0026thinsp;10PD; \u003csup\u003e3\u003c/sup\u003e=Corrected\u0026thinsp;=\u0026thinsp;orthotropia or ET or XT up to 10PD, undercorrected\u0026thinsp;=\u0026thinsp;residual XT\u0026thinsp;\u0026gt;\u0026thinsp;10PD, overcorrected\u0026thinsp;=\u0026thinsp;consecutive ET\u0026thinsp;\u0026gt;\u0026thinsp;10PD.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThere was a statistically significant correlation between the motor outcome and both the surgical target angle and the amount of recession in group 1 but not in group 2 (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Success rates were higher in group 1 than 2 for angles up to 25∆. For larger angles, bilateral surgery was more successful (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). For all surgical target angles, lateral incomitance was more frequent in group 1 than 2 (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). The rate of lateral incomiance was 71% after 10mm unilateral LR recession, but only 20% for smaller amounts of unilateral recessions. Most cases of lateral incomitance, however, showed limited ductions not exceeding \u0026minus;\u0026thinsp;1, with only 4 patients having \u0026minus;\u0026thinsp;2 limitations, on the final follow-up. Of these 4 patients, 3 had had 10-mm and 1 had had 9-mm unilateral LR recession.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelation of the surgical outcome to the surgical target angle and amount of lateral rectus recession.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMotor outcome\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSurgical target angle (∆)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eRecession per LR muscle (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTotal recession for both LR muscles (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eGroup 1:\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorrected (within 10∆ of orthotropia)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.19+/-5.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.46+/-0.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndercorrected (residual XT\u0026thinsp;\u0026gt;\u0026thinsp;10∆)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27.67+/-5.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9.22+/-1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e.008*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e.006*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eGroup 2:\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorrected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.85+/-4.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.85+/-0.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.55+/-1.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndercorrected\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23+/-3.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.58+/-0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.16+/-1.04\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOvercorrected (consecutive ET\u0026thinsp;\u0026gt;\u0026thinsp;10∆)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.33+/-7.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.67+/-1.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.33+/-2.08\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e.208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e.190\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.229\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eComparing angles of deviation on entry versus 1 week postoperatively, there was a significant decrease of deviation in groups 1 and 2 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001). On comparing postoperative angles of deviation at 1 week versus the last follow-up, an insignificant decrease in distant angles and an insignificant increase in near angles of deviation were noted in both groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;.05).\u003c/p\u003e \u003cp\u003eComparing the incidence of lateral incomitance documented at entry into the study versus 1 week postoperatively and the last follow-up, a significant increase was noted in group 1 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.001 and .022, respectively). Comparing those in group 2, it was noted that lateral incomitance was less frequent at 1 week (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.607) and the last follow-up (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.001) than on entry into the study. Lateral incomitance decreased significantly in both groups on the last follow-up versus 1 week postoperatively (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.001). Lateral rectus ductions were less limited on the final follow-up, as compared to the first postoperative week, by a mean of 0.72+/-0.84 in group 1 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;.001) and by a mean of 0.09+/-0.37 in one LR and 0.06+/-0.34 in the other LR in group 2 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;.057 and .159, respectively).\u003c/p\u003e \u003cp\u003eThese results suggest essentially equal success rates for unilateral and bilateral surgery for exotropia. Success rates are superior after unilateral surgery for angles up to 25∆. For larger angles, bilateral surgery is better. There was, however, persistently higher frequency of lateral incomitance after unilateral surgery for all surgical target angles. The latter is most pronounced after 10mm unilateral LR recession.\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThe goal of strabismus surgery is to align the eyes, thereby preserving stereoacuity and visual acuity. The traditional treatment for both exotropia and esotropia (ET) is two-muscle strabismus surgery as either bilateral rectus muscle recession or combined unilateral rectus recession and antagonist rectus resection. One-muscle recession has various theoretical advantages over two-muscle surgery, namely limiting surgery to one eye, leaving other muscles untouched if repeat surgery is needed, shorter operative time with less anesthetic exposure, and less surgical complications.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e However, this procedure is controversial because of concerns regarding undercorrection and/or induced incomitance.\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan additionalcitationids=\"CR6 CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eSeveral studies have shown that one-muscle surgery provides promising outcomes, especially in small to moderate horizontal deviations, with success rates ranging from 73\u0026ndash;100%.\u003csup\u003e[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17 CR18 CR19\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e Conversely, other studies reported a\u0026thinsp;\u0026lt;\u0026thinsp;60% success rate,\u003csup\u003e[\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e one of which reported only 36% success, with 63% under- and 1% overcorrection.\u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e Inconsistent surgical outcomes between studies were likely caused by different inclusion criteria, surgical dosages, definition of success, follow-up time, demographic backgrounds, and variable surgeon technique and experience.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e The success rate obtained in the present study after single-muscle surgery was 83%, and was slightly higher than that obtained in the two-muscle group. In agreement with previous studies,\u003csup\u003e[\u003cspan additionalcitationids=\"CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e in the present study, all failures in the single-muscle group were due to undercorrections, and lateral incomitance was significantly higher than after bilateral surgery.\u003c/p\u003e \u003cp\u003eSince one muscle surgery has been studied in only small to moderate angle strabismus and the majority of unsuccessful cases were undercorrections,\u003csup\u003e[\u003cspan additionalcitationids=\"CR7 CR8 CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21 CR22 CR23 CR24 CR25 CR26 CR27 CR28 CR29 CR30\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e it may not be effective against large angle strabismus. A dose-response relationship study suggested that one muscle recession can be used in XT or ET\u0026thinsp;\u0026lt;\u0026thinsp;30∆.\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e In agreement, the present study included XT with angles 14 to 35∆, to avoid the need for recessions larger than 10 mm, which could be more demanding due to difficult exposure and the close proximity to the site of insertion of the inferior oblique muscle, as well as to attempt to minimize the degree of postoperative lateral incomitance. Moreover, the 3 cases of 35∆ XT were treated by only 10-mm recession (the same as the 30∆-XT), assuming that the remaining 5∆ can be easily fused in patients who have a potential for fusion.\u003c/p\u003e \u003cp\u003eThe surgical dosages for unilateral LR recession differed among different studies.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e Feretis et al.\u003csup\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e used large unilateral LR recessions of 11.5 mm to 12 mm for small angle exodeviations of 15\u0026ndash;16∆ in 10 patients. Although all cases were initially overcorrected, they all achieved orthophoria by 4 weeks. Nelson et al.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e reported a 94% success rate in 55 patients with XT 15\u0026ndash;20∆ receiving unilateral LR recessions of 7, 7.5, and 8 mm, respectively. Later, Wang and Nelson\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e matched specific magnitudes of unilateral LR recession (7 mm to 10 mm) to specific magnitudes of XT (15 to 35 ∆) and reported a success rate of 76% and a significant correlation between the preoperative angle of deviation and final success. Almahmoudi et al.\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e performed 6 to 11 mm of unilateral LR recession for 12 to 30∆ of XT in 30 patients, with initial success in 73.3% that dropped to 63.3% on the last follow-up due to late undercorrection. Unlike the study of Wang and Nelson,\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e the authors reported no significant correlation of success rate to preoperative angle.\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e Lekskul et al. performed unilateral LR recessions, in 25 patients, of 8, 9 and 10 mm for 15, 20 and 25 ∆ of XT, respectively, and reported a success rate of 76%, with no significant differences between success rates recorded for the different amounts of preoperative deviations.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e In the present study, the surgical doses were essentially based on Wright\u0026rsquo;s surgical tables, with modifications\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). A success rate of 83% was recorded in the current study after unilateral LR recession, and there was a statistically significant correlation between the motor outcome and both the surgical target angle and the amount of recession in group 1 but not in group 2.\u003c/p\u003e \u003cp\u003eThe previous discussion reflects the variability in surgical dosages among different studies. These results emphasize the assumption that it is not merely the surgical dosage that affects the final results, but, more importantly, the patient\u0026rsquo;s response to surgery and the ability to regain fusion.\u003c/p\u003e \u003cp\u003eOne of the major advantages of unilateral LR recession is the small percentage of overcorrection. Consecutive ET after strabismus surgery may lead to intolerable diplopia and loss of stereopsis, requiring further intervention. Several authors also reported no overcorrection after unilateral surgery,\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e or at least noted overcorrection only in the early postoperative period, which disappeared over time.\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan additionalcitationids=\"CR27 CR28\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e Consecutive ET following unilateral LR recession was reported in some studies at a low rate ranging from 1\u0026ndash;10% of the patients.\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]\u003c/sup\u003e In the current study, a single case showed a consecutive ET exceeding 10∆ at 1 week, but achieved orthotropia on the last follow-up. On the other hand, 3 cases in the bilateral surgery group had persistent consecutive ET exceeding 10∆, which reflects the advantage of unilateral surgery.\u003c/p\u003e \u003cp\u003eOne complication after unilateral LR recession is lateral incomitance. Although several studies reported no incomitance after unilateral recession,\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e yet others did.\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e The low incidence of lateral incomitance after unilateral LR recession was attributed to the long arc of contact of the LR muscle and the position of functional equator that is posterior to the anatomical equator.\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e Two studies reported lateral incomitance in some patients undergoing unilateral LR recession exceeding 9 mm, but this complication was noted only in the early postoperative period, decreased with time, and disappeared 2\u0026ndash;4 months after surgery.\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e One study, however, reported lateral incomitance in 32% in the early postoperative period, that persisted till at least 3 months after surgery. The authors, however, stated that abduction limitation was mild in all cases, and was functionally and cosmetically acceptable.\u003c/p\u003e \u003cp\u003eOne study recommended that unilateral LR recession should not exceed 9 mm to lower the risk of lateral incomitance.\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e On the other hand, another study reported no lateral incomitance with unilateral LR recessions up to 10 mm.\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e In the present study, unilateral LR recessions were performed up to 10 mm. Lateral incomitance was recorded at a rate of 61.5% at one week, which went down to 29.5% on the final follow-up. Most cases, however, showed limited ductions not exceeding \u0026minus;\u0026thinsp;1, with only 4 patients having \u0026minus;\u0026thinsp;2 limitations, on the final follow-up. Of these 4 patients, 3 had had 10-mm LR recession and 1 had had 9-mm recession. Moreover, 5/7 patients (71%) who had 10-mm unilateral LR recession developed lateral incomitance, while only 4/16 (25%) of those who received unilateral 9-mm recession showed incomitance. The overall incidence of lateral incomitance for recessions below 10mm was 8/40 (20%). This supports the previous recommendation that unilateral LR recession should not exceed 9 mm.\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn conclusion, unilateral LR recession offers a better alternative to bilateral LR recession for correction of XT up to 25∆, without exceeding 9 mm of recession. It is not advisable for larger angles as there is risk of undercorrection and persistent lateral incomitance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflict of interest:\u003c/h2\u003e \u003cp\u003eThe authors report no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eRK.Idea of manuscript, examined and operated on patients, collected literature, analyzed data, wrote the manuscript.RE.Filled in excel sheet.REM.Filled in excel sheet.HE.Examined and operated on patients, revised the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWang L, Nelson LB. One-muscle strabismus surgery. Curr Opin Ophthalmol. 2010;21(5):335\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGurland J, Vagge A, Nelson LB. One-muscle strabismus surgery: a review. J Pediatr Ophthalmol Strabismus. 2018;55(5):288\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKimberly MS, Areaux RG. Unilateral horizontal rectus muscle recessions for pediatric comitant strabismus. J Binocul Vis Ocul Motil. 2022; 72(3):147\u0026ndash;150.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWright KW, Strube YNJ. Appendix A: Surgical numbers. In: Wright KW, Strube YNJ, eds. Color Atlas of Strabismus Surgery: Strategies and Techniques. 4th ed. Springer New York 2015: pp 191\u0026ndash;192.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLekskul A, Wuthisiri W, Jarupanich N. A prospective study of one-muscle surgery in 15\u0026ndash;25 prism diopters horizontal comitant strabismus in adults. Clinical Ophthalmology 2021;15:3669\u0026ndash;3678.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeutsch JA, Nelson LB, Sheppard RW, Burke MJ. Unilateral lateral rectus recession for the treatment of exotropia. Ann Ophthalmol. 1992;24(3):111\u0026ndash;113.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKamlesh DS. Long-term results of unilateral lateral rectus recession in intermittent exotropia. J Pediatr Ophthalmol Strabismus. 2003;40 (5):283\u0026ndash;287.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZak TA. Results of large single medial rectus recession. J Pediatr Ophthalmol Strabismus. 1986;23(1):17\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNelson LB, Bacal DA, Burke MJ. An alternative approach to the surgical management of exotropia\u0026ndash;the unilateral lateral rectus recession. J Pediatr Ophthalmol Strabismus. 1992;29(6):357\u0026ndash;360.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOlitsky SE. Early and late postoperative alignment following unilateral lateral rectus recession for intermittent exotropia. J Pediatr Ophthalmol Strabismus. 1998;35(3):146\u0026ndash;148.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eProcianoy E, Justo DM. Results of unilateral medial rectus recession in high AC/A ratio esotropia. J Pediatr Ophthalmol Strabismus. 1991;28(4):212\u0026ndash;214.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeakley DR Jr, Stager DR. Unilateral lateral rectus recessions in exotropia. Ophthalmic Surg. 1993;24(7):458\u0026ndash;460.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMenon V, Singla MA, Saxena R, Phulijele S. Comparative study of unilateral and bilateral surgery in moderate exotropia. J Pediatr Ophthalmol Strabismus. 2010;47(5):288\u0026ndash;291.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHopker LM, Weakley DR. Surgical results after one-muscle recession for correction of horizontal sensory strabismus in children. J AAPOS. 2013;17(2):174\u0026ndash;176.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePollard ZF, Manley D. Unilateral medial rectus recession for small-angle esotropia. Arch Ophthalmol. 1976;94(5):780\u0026ndash;781.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpierer O, Spierer A. Unilateral lateral rectus recession is an effective surgery for intermittent exotropia in young children. BMC Ophthalmol. 2021;21(1):10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLyu IJ, Park KA, Oh SY. Long-term surgical outcomes and factors for recurrence after unilateral lateral rectus muscle recession. Br J Ophthalmol. 2016;100(10):1433\u0026ndash;1436.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpierer A, Ben-Simon GJ. Unilateral and bilateral lateral rectus recession in exotropia. Ophthalmic Surg Lasers Imaging. 2005;36 (2):114\u0026ndash;117.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Nelson LB. Outcome study of unilateral lateral rectus recession for small to moderate angle intermittent exotropia in children. J Pediatr Ophthalmol Strabismus. 2010;47(4):242\u0026ndash;247.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlmahmoudi FH, Al Shamrani M, Khan AM. The use of one muscle recession for horizontal strabismus. Saudi J Ophthalmol. 2018;32 (3):200\u0026ndash;203.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCogen MS, Roberts BW. Graded unilateral supramaximal medial rectus recession for moderate angle esotropia. Binocul Vis Strabismus Q. 2006;21(3):147\u0026ndash;153.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Wang X. Comparison between graded unilateral and bilateral medial rectus recession for esotropia. Br J Ophthalmol. 2012;96 (4):540\u0026ndash;543.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrin TR, Nelson LB. Large unilateral medial rectus recession for the treatment of esotropia. Br J Ophthalmol. 1987;71 (5):377\u0026ndash;379.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStack RR, Burley CD, Bedggood A, Elder MJ. Unilateral versus bilateral medial rectus recession. J AAPOS. 2003;7(4):263\u0026ndash;267.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang L, Nelson LB. Outcome study of graded unilateral medial rectus recession for small to moderate angle esotropia. J Pediatr Ophthalmol Strabismus. 2011;48(1):20\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh SY, Choi HY, Lee JY, Oh SY. Surgical outcomes related to degree of unilateral lateral rectus muscle recession in intermittent exotropia of 20 prism diopters. Jpn J Ophthalmol. 2020;64(6):621\u0026ndash;627.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpierer O, Spierer A, Glovinsky J, Ben-Simon GJ. Moderate- angle exotropia: a comparison of unilateral and bilateral rectus muscle recession. Ophthalmic Surg Lasers Imaging. 2010;41(3):355\u0026ndash;359.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim HJ, Kim D, Choi DG. Long-term outcomes of unilateral lateral rectus recession versus recess-resect for intermittent exotropia of 20\u0026ndash;25 prism diopters. BMC Ophthalmol. 2014;14:46.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuh SY, Choi J, Kim SJ. Comparative study of lateral rectus recession versus recession-resection in unilateral surgery for intermittent exotropia. J AAPOS. 2015;19(6):507\u0026ndash;511.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang HK, Kim MJ, Hwang JM. Predictive factors affecting long-term outcome of unilateral lateral rectus recession. PLoS One. 2015;10(9): e0137687.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim H, Yang HK, Hwang JM. Comparison of long-term surgical outcomes between unilateral recession and unilateral recession-resection in small-angle exotropia. Am J Ophthalmol. 2016;166:141\u0026ndash;148.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFeretis D, Mela E, Vasilopoulos G. Excessive single lateral rectus muscle recession in the treatment of intermittent exotropia. J Pediatr Ophthalmol Strabismus 1990;27:315\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"international-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"inte","sideBox":"Learn more about [International Ophthalmology](https://www.springer.com/journal/10792)","snPcode":"10792","submissionUrl":"https://submission.nature.com/new-submission/10792/3","title":"International Ophthalmology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4598867/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4598867/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eTo compare the effect of unilateral versus bilateral lateral rectus (LR) recession for correction of small to moderate exotropia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e Records of all patients with exotropia (XT) 14 to 35 prism diopters (∆), operated upon by the authors, were included in a retrospective study to compare the effect of unilateral (Group 1) versus bilateral (Group 2) LR recession. The study end-point was the last follow-up visit scheduled at least 3 months postoperatively. A successful outcome was defined as 0 to 10∆ of horizontal tropia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003eThe study included 154 patients (47 in Group 1 and 107 in Group 2). Patients were followed up for 3 to 120 months (26.7+/-24.88). A successful outcome was achieved in 83% in Group 1 and 82.2% in Group 2 (\u003cem\u003ep\u003c/em\u003e=.976), with higher success in group 1 for surgical target angles up to 25∆. All failures in Group 1 were due to undercorrections., while the 17.8% failure rate in Group 2 comprised 15% undercorrections and 2.2% overcorrections (\u003cem\u003ep\u003c/em\u003e=.419). Persistent lateral incomitance was seen in 29.5% in Group 1 versus 2.3% in Groups 2 (\u003cem\u003ep\u003c/em\u003e \u0026lt;.001). Lateral incomitance was encountered in 71% of those undergoing 10mm unilateral recessions, versus 20% of those who had smaller recession doses. Limited ductions were mild, and exceeded -1 in 4 cases: 3 had had 10mm and 1 had had 9mm unilateral LR recession.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eUnilateral and bilateral LR recessions offer essentially equal success rates. Unilateral recessions are advised for angles up to 25∆, without exceeding 10mm.\u003c/p\u003e","manuscriptTitle":"Unilateral versus bilateral lateral rectus recession for correction of small to moderate angle exotropia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-18 15:21:31","doi":"10.21203/rs.3.rs-4598867/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-16T06:59:42+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-08-07T20:38:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"47889523080513064740569542759821203297","date":"2024-08-06T06:09:42+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-30T15:11:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-19T07:15:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-19T07:12:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"International Ophthalmology","date":"2024-06-18T09:19:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"international-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"inte","sideBox":"Learn more about [International Ophthalmology](https://www.springer.com/journal/10792)","snPcode":"10792","submissionUrl":"https://submission.nature.com/new-submission/10792/3","title":"International Ophthalmology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e3afa891-9eac-469d-9d67-9bacac9a5e83","owner":[],"postedDate":"July 18th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-21T16:11:09+00:00","versionOfRecord":{"articleIdentity":"rs-4598867","link":"https://doi.org/10.1007/s10792-024-03324-1","journal":{"identity":"international-ophthalmology","isVorOnly":false,"title":"International Ophthalmology"},"publishedOn":"2024-10-17 15:57:45","publishedOnDateReadable":"October 17th, 2024"},"versionCreatedAt":"2024-07-18 15:21:31","video":"","vorDoi":"10.1007/s10792-024-03324-1","vorDoiUrl":"https://doi.org/10.1007/s10792-024-03324-1","workflowStages":[]},"version":"v1","identity":"rs-4598867","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4598867","identity":"rs-4598867","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}