Evaluation of distance and near stereoacuity and fusional vergence in intermittent exotropia

Aim: To evaluate the role of distance and near stereoacuity and fusional vergence in patients with intermittent exotropia [X(T)] and their change after surgery. Materials and Methods: This prospective interventional institution-based clinical study included 31 cases of X(T) requiring surgery and 33 age, sex-matched controls. All subjects underwent complete orthoptic assessment including near stereopsis (Randot stereogram) and distance stereopsis by polaroid stereo-projector apparatus using special paired slides and fusional vergence assessment at distance and near prism bar at baseline and one week, one month, three months and six months after surgery in X(T). Results: The successful surgical alignment rate was 74.2%. Preoperatively, cases demonstrated significantly poor distance and near stereoacuity, compared to controls ( P P Conclusion: Early detection of abnormal stereoacuity (near and if possible distance) and near fusional vergence amplitudes may help to decide proper timing of surgery in X(T).     

Binocular status after surgery for constant and intermittent exotropia

PURPOSE: To investigate whether constant exotropia patients with a previous history of intermittent exotropia X(T), like X(T) patients, can achieve postoperative bifixation, and whether they have a better postoperative sensory outcome than those without previous history of X(T). DESIGN: Prospective comparative clinical study. METHODS: Sixty-three consecutive patients with intermittent or constant exotropia were divided into three groups: X(T) (group 1), constant exotropia with a previous history of X(T) (group 2), and constant exotropia without previous history of X(T) (group 3). The surgical outcomes were assessed and compared in motor and sensory terms separately between the three groups. Successful motor alignment was defined as within 8 prism diopters (PD) (exo or eso). A stereoacuity < or =60 seconds of arc was considered as bifixation, and a stereoacuity < or =800 seconds of arc was considered as gross stereopsis. RESULTS: The successful motor alignment rates of group 1, group 2, and group 3 were 79%, 71%, and 67%, respectively (group 1 vs group 2, P = .826; group 1 vs group 3, P = .551; group 2 vs group 3, P = 1.000). Twenty-five (74%) patients in group 1 achieved bifixation and none achieved in group 2 or group 3 (group 1 vs group 2, P = .001; group 1 vs group 3, P = .001). Meanwhile, 34 patients (100%) in group 1, 11 (79%) in group 2, and 5 (33%) in group 3 achieved gross stereopsis (group 1 vs group 2, P = .021; group 2 vs group 3, P = .025; group 1 vs group 3, P = .001). Compared with patients in the two constant exotropia groups, patients in X(T) group had a significantly better sensory outcome in both bifixation and gross stereopsis. Patients in group 2 had a better sensory outcome than those in group 3 in gross stereopsis. CONCLUSIONS: Constant exotropia patients with a previous history of X(T) have a better postoperative sensory outcome in gross stereopsis than those without previous history of X(T), but a worse surgical sensory outcome when compared with X(T) patients in both bifixation and gross stereopsis. Constant exotropia patients decompensated from X(T) may have missed the best time for treatment.     

LACTOSE control scoring helps predict surgical outcomes for childhood intermittent exotropia

ObjectiveTo determine whether preoperative Look And Cover, then Ten seconds of Observation Scale for Exotropia (LACTOSE) control scores can predict surgical outcomes in children with intermittent exotropia.DesignRetrospective interventional case series from a university-based tertiary eye care centre.ParticipantsA total of 350 patients with basic-type intermittent exotropia who underwent bilateral lateral rectus recession between 3 and 10 years of age from January 2014 to December 2017.MethodsAll patients were preoperatively assessed for their degree of control at both distance and near according to LACTOSE scoring system. Demographic, clinical, and oculomotor data before and after surgery were collected and analyzed with regard to the degree of control. Surgical success was defined as an alignment between 10 prism diopters (PD) of exodeviation and 5 PD of esodeviation at both distance and near.ResultsYounger age, lower visual acuity, worse stereoacuity, and larger angle of deviation were associated with higher (i.e., worse) LACTOSE control scores. Of the 350 patients having surgery, 169 (48.3%) were followed for more than 12 months postoperatively. Surgical success was achieved in 132 (78.1%) patients at 12 months after surgery. The only significant predictor of surgical success was preoperative LACTOSE score. There was a significant inverse relationship between LACTOSE scores and surgical success rates for both distance and near scores (p = 0.004 and 0.023, respectively).ConclusionsHigher distance and near LACTOSE scores representing worse control of deviation were associated with higher rates of surgical failure in children with intermittent exotropia. This finding indicates that surgical outcome of intermittent exotropia can be predicted by preoperative LACTOSE scores.     

外斜视术后远期眼位变化及相关影响因素的研究

目的 观察外斜视患者术后远期眼位变化并分析其相关影响因素.方法 对28例外斜视手术患者随访观察,分别于术后第3d和术后1年用三棱镜遮盖法检查患者斜视度;同视机和Titmus立体图检查立体视觉.术后眼位正位标准为斜视角≤±10△.所有结果采用SPSS 17.0统计软件统计学处理.结果 术后第3d和术后1年的眼位正位率为96.4％和64.3％,斜视度平均值为-4.32△±4.57△和 -8.64△±8.70△,经统计学分析有显著性差异(t=-0.445,P=0.01 3),术后1年斜视度回退量均值为-4.32△±8.61△.对16例患者术前和术后的立体视锐度进行比较,发现术后立体视锐度较术前有所提高,但术前立体视锐度与远期眼位变化无明显相关性其它因素如患者手术年龄,术前斜视度等对术后远期眼位无明显影响.结论 外斜视患者斜视矫正术后远期眼位有回退现象,单因素如术前立体视锐度、手术年龄、术前斜视度等与其无明显相关性,眼位回退可能受多种因素的共同影响.     

单眼外直肌后徙术治疗儿童间歇性外斜视的疗效

目的探讨单眼外直肌后徙术对中、小度数儿童间歇性外斜视的疗效。方法回顾性系列病例研究。2009年4月至2010年3月期间行单眼外直肌后徙术治疗、斜视度为15^△-35^△的间歇性外斜视儿童69例。采用三棱镜加交替遮盖法测定患儿注视6m和33cm的斜视度,根据看远斜视度定量行7-10mm单眼外直肌后徙术。随访时间≥6个月。手术前后采用Worth四点灯检查中心和周边融合,采用Titmus立体视图测定立体视锐度。疗效评价标准以眼位-8^△-0^△为正位;第一眼位与侧向注视的斜视度相差≥10^△为非共同性阳性。采用X^2检验对数据进行分析。结果术后1-3d和≥6个月随访正位率分别为81％和62％,欠矫率分别为12％和36％。斜视度为30^△、35^△（外直肌后徙9．5-10mm）者欠矫率较高。术前与术后远期随访比较,具有正常中心融合和周边融合者比例的差异有统计学意义（X^2=21．9,P〈0．01;X^2=14．0,P〈0．01）,术后明显高于术前;具有正常立体视功能者比例的差异有统计学意义（X^2=15．0,P〈0．01）,术后明显高于术前。术后远期随访未见眼位非共同性阳性者。结论单眼外直肌后徙术治疗斜视度为15^△-25^△的儿童间歇性外斜视安全、有效。     

Prognostic factors for strabismus surgery after cataract surgery

PURPOSE: To evaluate the clinical features of strabismus that present after cataract surgery and determine the motor and sensory results after surgical correction of the strabismus. SETTING: Department of Ophthalmology, the Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. METHODS: Thirty-one patients who had strabismus surgery after cataract surgery between January 1996 and June 2004 were included in the study. The clinical features of strabismus and the factors contributing to successful strabismus surgery results were retrospectively analyzed. Sensory functional tests were performed postoperatively. RESULTS: Fifteen patients (48.4%) had exotropia. The types of cataract included traumatic (35.5%), congenital (32.3%), and senile (25.8%). Prolonged deviation was the statistically significant factor contributing to final alignment (P = .023). Fourteen of 31 patients had stereoacuity measurement; all achieved a stereoacuity of 3000 seconds of arc. Five of the 14 patients (35.7%) had better than 200 seconds of arc. CONCLUSIONS: The anatomical results and sensory function of the patients were generally good. When appropriate, surgical intervention to treat strabismus after cataract surgery should be offered, and this is important for restoration of fusion.     

The long-term result of slanted medial rectus resection in exotropia of the convergence insufficiency type

PURPOSE: To evaluate the long-term results of slanted medial rectus (MR) resection for intermittent exotropia (X(T)) of the convergence insufficiency type. METHODS: In all, 10 patients with an X(T) greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. Patients received slanted bilateral MR resection. The upper edge of the MR was resected according to the distance exodeviation and the lower edge of the MR was resected according to near exodeviation. The postoperative follow-up period was between 6 and 62 months with a mean of 38.9 months. The paired t-test was used to compare: mean distance angle of deviation preoperatively and postoperatively; mean near angle of deviation preoperatively and postoperatively; and mean near-distance exodeviation difference preoperatively and postoperatively. RESULTS: Bilateral slanted MR resections reduced mean exodeviation at distance from 23.0+/-7.2 to 16.3+/-5.4 PD (P=0.03); mean exodeviation at near from 34.3+/-7.7 to 24.6+/-6.9 PD (P=0.01); and mean near-distance difference from 11.4+/-2.6 to 8.3+/-3.5 PD (P=0.04). At the final follow-up examination, all patients demonstrated an exodeviation of 10 PD or more at distance and near, and the exodeviation difference between distance and near deviation was within 10 PD in five of the 10 patients. Three patients had an esodeviation at distance after surgery, but all resolved within 4 weeks. CONCLUSIONS: Bilateral slanted MR resections in patients with X(T) of the convergence insufficiency type resulted in undercorrection in all patients.     

Relationship between motor alignment at postoperative day 1 and at year 1 after symmetric and asymmetric surgery in intermittent exotropia

PURPOSE: To evaluate the relationship between the motor alignment at postoperative day 1 and at year 1 following bilateral lateral rectus recession (BLR, symmetric surgery) and unilateral lateral rectus recession-medial rectus resection (R&R, asymmetric surgery) for the treatment of intermittent exotropia, X(T). METHODS: Forty-six patients with basic or pseudo-divergence excess type of X(T) underwent BLR and 57 patients underwent R&R. The motor alignment at postoperative day 1 was classified as overcorrected by 11-20 prism diopters (PD), overcorrected by 1-10 PD, orthotropic, or undercorrected by 1-10 PD of exotropia. RESULTS: There was a statistically significant relationship between the alignment at postoperative day 1 and at year 1 following both R&R and BLR surgery (r = 0.74, r = 0.51, respectively, P <.05). Patients overcorrected by 1-20 PD had a significantly higher success rate than those undercorrected by 1-10 PD on postoperative day 1 (P <.05). For R&R, a postoperative day 1 alignment of 1-10 PD resulted in the highest success rate of 73.7%. For BLR, a postoperative day 1 alignment of 11-20 PD showed the highest success rate of 76.9%. There were no significant differences in the success, undercorrection and overcorrection rates between the two surgical procedures after a 1-year postoperative period. CONCLUSIONS: The alignment at postoperative day 1 can be a predictive factor of the surgical outcome in X(T). A postoperative day 1 overcorrection of 11-20 PD following BLR surgery and an overcorrection of 1-10 PD following R&R can lead to good results.     

Relationship between Control Grade,Stereoacuity and Surgical Success in Basic Intermittent Exotropia

PurposeThis study was conducted to identify the relationship between control grade, stereoacuity and surgical success in basic intermittent exotropia.MethodsThis retrospective study involved 44 basic intermittent exotropia patients who underwent strabismus surgery and completed at least 6 months of follow-up. The 44 patients were divided into three subgroups according to their control grade: group 1 (good control group, n = 12), group 2 (fair control group, n = 18), and group 3 (poor control group, n = 14). Evaluation was done to identify the relationships between near and distance stereoacuity and control grade, and between surgical success and control grade. Surgical success was defined as ocular alignment between 5 prism diopters esodeviation and 10 prism diopters exodeviation in the primary position at the final visit.ResultsMean near stereoacuity measured by the graded circle test was 57.50 seconds of arc (seconds) in group 1, 77.77 seconds in group 2, and 131.43 seconds in group 3 (p < 0.01). Mean distance steroacuity measured by Mentor B-VAT II BVS contour circle was 108.33 seconds in group 1, 148.33 seconds in group 2, and 262.82 seconds in group 3 (p < 0.01). Ten patients (83.33%) in group 1, 12 (66.67%) in group 2, and 9 (64.29%) in group 3 obtained surgical success (p = 0.28).ConclusionsIn basic intermittent exotropia, better control grade was significantly accompanied by better stereoacuity. Better control grade was accompanied by higher surgical success rate but with no statistical significance.     

The use of the Newcastle Control Score in the management of intermittent exotropia

AIM: To evaluate the use of the Newcastle Control Score (NCS) in the management of intermittent exotropia (X(T)). Participants and methods: Children aged <11 years with X(T) had an assessment of NCS as part of routine management. Other data collected included visual acuity, near and distance alignment with alternating prism cover test and near (Frisby test) and distance stereoacuity (Frisby Davis Distance Stereotest (FD2TM)). Analysis involved correlation between baseline NCS, angle and stereoacuity, examination of change over time and logistic regression to determine predictors of surgery. RESULTS: Baseline data were obtained on 272 children and follow-up data on 157. Mean (SD) age was 4 (1.9) years. Complete NCSs were obtained for all except one child at baseline, and all children at follow-up. At baseline, total NCS and the home control component were correlated with near stereo (r = -0.22, p<0.01 and r = -0.19, p<0.02, respectively), near alignment (r = 0.34, p<0.001 and r = 0.19, p<0.02) and distance alignment (r = 0.30, p<0.001 and r = 0.26, p<0.001). The clinic near control component was correlated with near alignment (r = 0.39, p<0.001), but not near stereoacuity, and the clinic distance control with near alignment (r = 0.16, p<0.02), distance alignment (r = 0.27, p<0.001) and distance stereoacuity (r = -0.25, p<0.03). A high (poor) NCS (> or =4) at the latest follow-up predicted surgery (p<0.001, OR 29.3, 95% CI 6.2 to 138.7). CONCLUSION: The NCS is a useful measure of the clinical severity of X(T), can be used to serially assess improvement or deterioration and is a useful tool for the management of these patients.     

儿童内斜视矫正术后双眼单视的建立及影响因素

目的 观察和分析内斜视儿童眼位矫正术后双眼单视功能的建立情况及其影响因素.方法 回顾性系列病例研究.收集2008年11月至2011年9月间在山东大学附属省立医院眼科中心行共同性内斜视矫正手术并且术后随访眼位正位(≤±8△)的连续性病例111例.采用手电筒式Worth四点灯评估患儿的中心融合和周边融合;采用Titmus立体视图测定患儿的立体视锐度.采用x2检验比较不同内斜视类型之间周边融合建立的差异;采用Logistic回归分析内斜视类型、弱视治疗时间、手术年龄、两眼屈光参差差值、术后斜视度对周边融合建立的影响,并采用优势比(OR)进行比较.结果 111例内斜视儿童中,术后获得周边融合者68例(61.3％),其中获得中心融合者6例(5.4％);56例(50.5％)建立了不同程度的立体视.手术年龄(b=-0.842,P＜0.01)、弱视治疗时间(b=-0.135,P＜0.05)、最终随访的斜视度(b=-1.305,P＜0.05)与术后周边融合的建立呈负相关;两眼屈光参差差值与术后周边融合的建立不相关(b=-19.670,P＞0.05).4种内斜视类型之间术后周边融合建立的差异有统计学意义(x2=-15.977,P＜0.01),周边融合建立的困难程度依次为先天性内斜视(OR=1.0)、非调节性内斜视(OR=3.008)、部分调节性内斜视(OR=4.475)、高AC/A型内斜视(0R=82.217).结论 内斜视儿童手术年龄愈早、术前弱视治疗时间愈短、术后斜视度愈小,术后愈易建立周边融合;4种内斜视类型中,建立周边融合的难易顺序依次为先天性内斜视、非调节性内斜视、部分调节性内斜视、高AC/A型内斜视.     

Post-operative strabismus control and motor alignment for basic intermittent exotropia

AIM: To assess strabismus control and motor ocular alignment for basic exotropia surgery at 5y follow-up. METHODS: The medical records of 80 consecutive patients aged less than 17 years of age, who underwent surgery for basic exotropia by a single surgeon between years 2000 to 2009 and completed a minimum of 5y follow-up post-operatively were reviewed. Pre- and post-operative characteristics were documented at 1wk, 6mo, 1, 3 and 5y follow-up. Subjects at 5-year follow-up were assigned to the success group if they had a post-operative angle of deviation within 10 prism diopters of exotropia or within 5 prism diopters of esotropia for distance on prism cover test, and had moderate to good strabismus control. The remaining subjects were assigned to the failure group. RESULTS: Post-operative surgical success at one week was 75%, which decreased to 41% at 5y follow-up. The success group was noted to have more patching pre-operatively (P=0.003). The duration of patching a day (P=0.020) and total duration of patching pre-operatively (P=0.030) was higher in the success group. Surgical success at 1y (P=0.004) and 3y (P=0.002) were associated with higher surgical success at 5y follow-up. CONCLUSION: Post-operative motor alignment and strabismus control for basic exotropia surgery at 1y and beyond is associated with higher exotropia surgery success at 5-year follow-up. There is an association between pre-operative patching and 5-year surgical success of basic intermittent exotropia surgery.     

Unilateral lateral rectus muscle recession and medial rectus muscle resection with or without advancement for postoperative consecutive exotropia.

PURPOSE: To evaluate the effectiveness of unilateral lateral rectus muscle recession and medial rectus muscle resection with or without advancement in treating postoperative consecutive exotropia. METHODS: We performed a retrospective review on 31 patients with consecutive exotropia who were treated with unilateral lateral rectus muscle recession and medial rectus muscle resection (17 patients) or unilateral lateral rectus muscle recession and medial rectus muscle partial resection combined with advancement (14 patients). All patients had exotropia with a less than 10 prism diopters (PD) distance near-disparity. The characteristics studied before surgery included type of esotropia surgery, detection of amblyopia, presence of an "A" or "V" pattern, dissociated vertical deviation, limitation of adduction, deviation angle measurement, and forced duction testing. Ocular alignment and status of adduction postoperatively at the last follow-up were recorded. RESULTS: Nineteen patients (61.3%) had amblyopia, 17 patients (54.8%) had limitation of adduction, 8 patients (25.8%) had dissociated vertical deviation, and 5 patients (16.1%) had an "A" or "V" pattern. The mean preoperative exodeviation was 47.3 PD. Overall 21 (67.7%) of 31 patients achieved a successful postoperative result (alignment within 10 PD of orthophoria). There was no significant difference in successful alignment in patients treated with unilateral medial rectus muscle resection compared with those treated with unilateral medial rectus muscle partial resection combined with advancement. There was no influence of amblyopia on the result. Twelve (70.6%) of the 17 patients with limited adduction preoperatively showed normalization of adduction postoperatively. CONCLUSIONS: Unilateral lateral rectus muscle recession and medial rectus muscle resection with or without advancement is an effective alternative for treating postoperative consecutive exotropia.     

Y-splitting medial rectus muscle and recession in treatment for convergence excess esotropia

AIM: To evaluate the surgical outcome of medial rectus (MR) recession with Y-splitting procedure in treatment of esotropia with convergence excess. METHODS: Medical records were retrospectively reviewed for those patients who underwent surgical treatment for their convergence excess esotropia (CEET) between January 2018 and December 2020. Refractive error was examined by the equipment of the VS100 (Welch Allyn). The surgical approach was bilateral MR recession with Y-splitting. The amount of recession was calculated according to the deviation angle at distance. Ocular movement and ocular alignment at distance and near were evaluated pre- and post-operatively. Binocular sensory status was evaluated by the Bagolini striated glasses at near and distance, and by stereoacuity assessment at near using the Titmus test. RESULTS: Six patients with CEET were included in this study. Four of them were hyperopia and two of them were myopia. A mean of eso-deviation angle at distance had been changed from 27.3±13.02 prism diopters (PD) preoperatively to 1.83±1.60 PD postoperatively (P<0.05), while a mean of eso-deviation angle at near had been changed from 50.00±20.74 PD preoperatively to 6.83±0.98 PD postoperatively (P<0.05). Patients had obtained binocular vision postoperatively. CONCLUSION: The surgical approach of Y-splitting MR and recession is effective in treatment of CEET.     

Surgical results of patients with A-pattern horizontal strabismus.

PURPOSE: To investigate the surgical results of patients having horizontal strabismus with A-pattern associated with superior oblique overaction (SOOA). METHODS: Twenty patients with horizontal strabismus (12 exotropia [XT] and 8 esotropia [ET] with no previous strabismus surgery) with SOOA-associated A-pattern were analyzed retrospectively. Motor success was defined as a horizontal deviation of 8 prism diopters (PD) or less, 6 PD or less of vertical deviation in all gazes, and no greater than 8 PD of A-pattern. Stereoacuity was measured using the Titmus test (Stereo Optical, Chicago, IL). RESULTS: Sixty percent of patients had successful results at the final examination. No significant difference was found between the XT and ET patients in preoperative and postoperative horizontal deviations in the primary position, A-pattern collapse, or success rate (P >.05). Four patients had an induced postoperative vertical deviation. Among eight patients without stereoacuity preoperatively, four showed an average of 910 seconds of arc (40 to 3000 seconds of arc) after surgery. CONCLUSION: Simultaneous surgery on the horizontal and SO muscles in patients with horizontal strabismus with SOOA-associated A-pattern can achieve a relatively high surgical success rate and restore binocular function.     

单侧内直肌截除术治疗儿童残余性和复发性外斜视的疗效观察

目的：探讨单侧内直肌截除术治疗儿童残余性和复发性外斜视的有效性及安全性,评价其在不同外斜视类型及不同初次手术方式应用的差异性。

方法：回顾性病例系列研究。收集2009-01/2013-02在山东大学附属山东省立医院行单侧内直肌截除术治疗的残余性和复发性外斜视连续性病例48例48眼,观察术后第1d, 6wk以及末次随访(术后6～32mo)时患儿眼位、眼位非共同性、融合功能及立体视锐度情况。

结果：术后第1d手术正位率为83%(40/48),欠矫率为4%(2/48),过矫率为13%(6/48); 术后第6wk手术正位率为81%(39/48),欠矫率为13%(6/48),过矫率为6%(3/48); 末次随访时正位率为75%(36/48),欠矫率为25%(12/48),无1例过矫。不同初次手术方式和不同外斜视类型患儿末次随访时手术正位率的差异均无统计学意义(P=0.168、0.50)。术后所有病例均未出现眼球运动非共同性和眼球外转受限。

结论：单侧内直肌截除术是治疗儿童残余性和复发性外斜视的安全有效术式,其在不同外斜视类型及不同初次手术方式应用的疗效无差异。     

Surgical outcomes of symmetric and asymmetric surgery for intermittent exotropia with postoperative large early overcorrection

Purpose

To compare surgical outcomes between bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession-medial rectus resection (RR) for intermittent exotropia with overcorrection of 20 prism diopter (PD) or more on postoperative day 1.

Methods

A retrospective chart review identified 319 patients who underwent either BLR or RR for primary surgical treatment of intermittent exotropia between July 2008 and June 2011. The patients with basic type intermittent exotropia and overcorrection of 20 PD or more, at either near or distance, on postoperative day 1 and had more than 6 months of follow-up were included. Patients with simultaneous vertical and/or oblique muscle surgery and those with paralytic or restrictive strabismus were excluded. The pre- and post-operative deviation, visual acuity, and near stereoacuity were analyzed.

Results

Twenty-four patients were included. The mean postoperative day 1 alignment was 21.5 ± 6.2 PD esotropia at distance, and 13.8 ± 8.0 PD at near. Fourteen patients underwent BLR and 10 underwent RR. Three patients were wearing the base out prism below 15 PD at the last follow-up. The mean duration from the surgery to esotropia below 10 PD was 2.9 ± 1.1 weeks and 8.0 ± 7.1 weeks in the BLR and RR groups, respectively (p = 0.030). All three recurrent patients underwent RR. None of the patients completely lost stereoacuity, postoperatively.

Conclusions

In basic type intermittent exotropia with overcorrection of 20 PD or more on postoperative day 1, the overcorrection resolved faster and recurrence rates were lower in BLR group than in the RR group. Consecutive esotropia over 15 PD did not occur in both groups.     

Botulinum toxin augmented bilateral lateral rectus recession versus three muscles surgery in large-angle intermittent exotropia

AIM: To report the surgical outcomes of correcting large angle intermittent exotropia in adult patients by bilateral lateral rectus muscle recession with intraoperative use of botulinum toxin and to compare the results with those of bilateral lateral rectus muscle recession and unilateral medial rectus resection. METHODS: The medical records of patients who underwent surgical correction of large angle intermittent exotropia [exotropia >50 prism dioptre (PD)] were retrospectively reviewed. Two groups of patients were identified; Group I (21 patients) had bilateral lateral recti recession augmented with intraoperative botulinum toxin A (BTA) injection into the recessed muscles and group II (30 patients) were treated by bilateral lateral recti recession with unilateral medial rectus muscle resection. Preoperative data were extracted for age, gender, refraction, type of exotropia, angle of stereopsis and angle of deviation. The main outcome measures were the postoperative angle of deviation and stereoacuity angle by Titmus test measured at the end of one year of postoperative follow up. RESULTS: By the end of the first postoperative year, 10 patients in group I (47.6%) and 20 patients in group II (66.7%) achieved esotropia/esophoria <5 PD or exotropia/exophoria <10 PD. The difference in surgical success rate was not statistically significant (P=0.1) but there was a statistically significant higher rate of undercorrection in group I (P=0.03). On the other hand, 3 patients in group I (14.3%) and 5 patients in group II (16.7%) had improved stereopsis; this difference in the sensory outcome was not statistically significant (P=0.8). In the BTA augmented surgery group, good stereoacuity and smaller preoperative angle of deviation were associated with significantly higher surgical success rate (P=0.004, 0.01 respectively). CONCLUSION: BTA augmented bilateral lateral recti recession is associated with higher rate of undercorrection as compared to bilateral lateral recti recession with unilateral medial rectus resection in the correction of large angle intermittent exotropia. The surgical success rate in BTA augmented surgery group is observed to be higher in patients with preoperative smaller angle of deviation and in patients with good stereoacuity.     

两种术式治疗基本型间歇性外斜视的比较

目的 比较双眼外直肌后徙术与单眼一退一截术治疗基本型间歇性外斜视的手术疗效.方法 对行双眼外直肌后徙(A组)和单眼一退一截(B组)手术治疗的49例基本型间歇性外斜视病例进行了回顾性分析.A组26例,B组23例.采用三棱镜加交替遮盖法测定患者戴镜注视6m和33cm调节性视标的第一眼位斜视度,根据看远斜视度手术,所有手术均由同一医生完成.术后平均随访(13.8±9.4)月,疗效评价标准以眼位≤±8Δ为正位.结果 A组眼位正位率为53.8%,B组眼位正位率为82.6%,A、B两组眼位正位率的差异具有统计学意义(x2=4.59 P=0.032),B组眼位正位率高于A组.结论 基本型间歇性外斜视应首选单眼一退一截手术.     

Timely surgery in intermittent and constant exotropia for superior sensory outcome

PURPOSE: To determine whether time of strabismus surgery for patients with acquired intermittent exotropia and constant exotropia influences postoperative sensory outcome. METHODS: In a retrospective, cross-sectional study, 76 patients with acquired intermittent or constant exotropia and motor realignment were evaluated for postoperative sensory status. Age at surgery, duration of exotropia, and presence of intermittent or constant exotropia were correlated with postoperative sensory status. The 23 male and 53 female patients had an average age of 9.3 years at the time of surgery and a mean follow-up of 5.9 years. RESULTS: Patients had a significantly greater chance of having postoperative stereoacuity better than 60 seconds of arc (bifixation) if they were surgically aligned before 7 years of age (P <.01) or before 5 years of strabismus duration (P <.05), or with intermittent as compared with constant exotropia (P <.001). Patients with postoperative bifixation had earlier surgical intervention (P <.025) and shorter duration of exotropia (P <.025) than those with postoperative monofixation. CONCLUSIONS: Patients with intermittent or constant exotropia may achieve superior sensory outcome with motor realignment before age 7, before 5 years of strabismus duration, or while the deviation is intermittent.