间接性视神经损伤血流动力学改变与预后相关性

目的:探讨间接性视神经损伤患者眼血流动力学变化规律与预后的相关性。方法:应用彩色多普勒血流成像(CDFI)技术检测102例患者视网膜中央动脉、睫状后动脉、眼动脉收缩峰值速度(PSV)、舒张末期流速(EDV)、时间平均最大血流速度(TAMX)、阻力指数(RI),并对视力与血流改变、血流改变与预后的关系进行观察。结果:患者102例中,95例患者眼动脉、睫状后动脉PSV明显增加(P<0.05),EDV明显减低(P<0.05)、TAMX减低(P<0.05)、RI显著增高(P<0.01);102例患者视网膜中央动脉血流参数无显著差异(P>0.05)。视力越差,血流改变越明显,预后越差。结论:间接性视神经损伤患者眼动脉、睫状后动脉呈高速高阻血流动力学改变、血流改变越明显预后越差。     

彩色多普勒在间接性视神经损伤中的应用

目的 探讨间接性视神经损伤眼血流动力学变化规律,评价其临床应用价值.方法 应用彩色多普勒血流成像(CDFI)技术检测36例(36眼)间接性视神经损伤与30例(30眼)健康志愿者视网膜中央动脉、睫状后动脉、眼动脉收缩峰值速度(PSV)、舒张末期流速(EDV)、时间平均最大血流速度(TAMX)以及阻力指数(RI).结果 与正常组比较,患者组眼动脉、睫状后动脉PSV明显增加(P<0.01、P<0.05),EDV明显减低(P<0.05、P<0.01)、TAMX减低(P<0.05)、RI显著增高(P<0.01);视网膜中央动脉血流参数差异无统计学意义(P>0.05).结论 间接性视神经损伤者眼动脉、睫状后动脉呈高速高阻血流动力学改变,提示视神经损伤者存在血供不良.     

甲状腺相关眼病行眼外肌后徙松解术的疗效观察

目的探讨甲状腺相关眼病（TAO）致限制性斜视患者眼外肌后徙松解术后,视力、眼压、视野、视网膜中央动脉血流速度的变化。方法选择2002年1月至2004年1月于北京协和医院眼科诊治的17例（20只眼）因TAO致限制性斜视行手术治疗的患者,其中1例行上直肌断腱术、1例行上直肌悬吊术、1例行右下直肌后徙联合左上直肌后徙术,余14例（17只眼）行下直肌后徙术。20只患眼手术前、后均检查视力、眼压、视野,测量视网膜中央动脉血流速度,并进行对照比较。结果术后5只眼视力提高≥2行,15只眼维持术前视力;术前、后眼压和视野平均缺损情况比较,差异有统计学意义（P〈0．01）;术前、后视网膜中央动脉血流参数比较：术后收缩期峰值血流速度（PSV）、舒张末期血流速度（EDV）增加及阻力指数（RI）降低（P〈0．05）。结论TAO致限制性斜视患者于静止期行眼外肌后徙松解术治疗,不仅可消除复视,使眼球运动好转,而且能提高裸眼视力、缓解眼压、改善视野和视网膜中央动脉血流速度。（中华眼科杂志,2005,41：772—776）     

彩色多普勒超声在视网膜中央动脉阻塞的应用

目的应用彩色多普勒血流显像(colordopplerflowimagingCDFI)及脉冲多普勒(pulsewavedopplerPW)检测视网膜中央动脉阻塞病变(centralretinalarteryocclusionCRAO)球后各动脉血流参数,研究其血流动力学变化特征。方法应用CDFI及PW检测50例(50只眼)临床诊断为CRAO患者的眼动脉(ophthalmicarteryOA)、视网膜中央动脉(centralretinalarteryCRA)、睫状后短动脉(shortposteriorciliaryarterySPCA)的收缩期峰值血流速度(peaksystolicvelocityPSV)、舒张末期血流速度(enddiastolicvelocityEDV)、时间平均最大血流速度(timeaveragedmaximumvelocityTAMX)、搏动指数(pulsatilityindexPI)及阻力指数(resistanceindexRI)并与25例(50只眼)正常对照组及18例(23只眼)、缺血性视神经病变(ischemicopticneuropathyION)相应眼部球后各动脉血流参数进行统计学比较。结果与对照组比较CRAO组CRA的PSV、EDV及TAMX明显降低(P<0.01),PI、RI明显升高(P<0.01),SPCA的PSV、EDV、TAMX轻度降低但差异不显著(P>0.05),PI、RI变化无显著差异(P>0.05)。结论CDFI及PW可以根据CRAO血管血流动力学特征改变为临床诊断及鉴别诊断提供准确依据。     

糖尿病患者球后血管血流动力学变化分析

目的:观察糖尿病视网膜病变(diabetic retinopathy,DR)患者球后血管血流动力学的变化情况。方法:利用彩色多普勒超声诊断仪(color Doppler imagi-ning,CDI)测定61例(122眼)糖尿病视网膜病变患者球后血流状态,其中糖尿病无视网膜病变(NDR)48眼,糖尿病视网膜病变非增殖期(NPDR)40眼,糖尿病视网膜病变增殖期(PDR)34眼,并与正常人32例(64眼)进行对照。检测指标包括视网膜中央动脉、视网膜中央静脉、眼动脉血管的最大收缩期血流速度(PSV)、舒张末期血流速度(EDV)、搏动指数(PI)和阻力指数(RI)。结果:NDR组与正常对照组相比,视网膜中央动脉、视网膜中央静脉、眼动脉血管的最大收缩期血流速度(PSV)、舒张末期血流速度(EDV)、搏动指数(PI)和阻力指数(RI)无统计学差异,NPDR组、PDR组分别与正常对照组相比,视网膜中央动脉、视网膜中央静脉、眼动脉血管的最大收缩期血流速度(PSV)、舒张末期血流速度(EDV)、搏动指数(PI)和阻力指数(RI)均有变化,各检测指标比较有统计学意义(P<0.05)。NPDR组与PDR组之间比较,视网膜中央动脉、视网膜中央静脉、眼动脉血管的最大收缩期血流速度(PSV)、舒张末期血流速度(EDV)、搏动指数(PI)和阻力指数(RI)均有变化,各检测指标比较有统计学意义(P<0.05)。结论:CDI对DR患者球后血管血流动力学变化的检测有一定临床应用价值,对2型DM患者的治疗监测及预后评估有重要意义。     

彩色多普勒血流显像对中晚期青光眼的眼血流动力学研究

目的:观察中晚期青光眼患者的眼血流动力学变化、了解血管因素在中晚期青光眼患者视功能损害机制中的作用.方法:应用彩色多普勒检测20例(40只眼)正常人和21例(42只眼)中晚期青光眼的眼动脉、睫状后短动脉及视网膜中央动脉的血流参数.测定收缩期峰值速度(Peak Systolic Velocity,PSV),舒张末期速度(End Diast01ic Veloclty,EDV),计算其阻力指数(ResistiveIndex,RI).结果:青光眼组与正常组比较,青光眼组的眼动脉、视网膜中央动脉及睫状后短动脉的血流速度明显降低,阻力指数则明显增高,二者之间均有非常显著的差异(均P＜0.001).而慢性闭角青光眼及开角青光眼组无论在血流速度及阻力指数之间都无明显差异(P＞0.05).结论:中晚期青光眼患者因眼动脉、视网膜中央动脉及睫状后短动脉血流速度明显下降,引起局部血液循环障碍,青光眼的视功能损害与视神经的血供不足有密切联系.     

视网膜脱离患者球后血液动力学的研究

目的观测视网膜脱离(RD)患者的球后血流动力学。方法原发性视网膜脱离(RD)患者60例, 按部分性RD25只眼;完全性RD22只眼;完全性RD伴PVR-C级以上15只眼分为三组,共62只眼。对照组38例, 共58只眼。彩色多普勒超声指导下,采用脉冲多普勒超声检测眼动脉(OA)、视网膜中央动脉(CRA)、睫状后动脉 (PCA)收缩期(PSV)、舒张期(ESV)、平均血流速度(AV)及阻力指数(RI)、搏动指数(PI)。结果三组RD患者与对照组的OA血流速度无明显差异(P>0．05);CRA、PCA的PSV、EDV、AV血流速度均减低(P<0．01);PI、RI值无显著性差异(P>0．05);且随着RD病情的加重各血流指标减低的更为明显,但组间差异无显著性(P>0．05)。结论视网膜脱离患者的血流动力学变化直接影响到视网膜的微循环状态,这为视网膜脱离的病理机制研究及药物辅助治疗提供了有力依据。     

血管显微分离在眼外肌手术中应用的临床研究

目的斜视矫正手术有时需要在一只眼上同时离断3条或3条以上直肌,因而过多地损伤了睫状前动脉,导致眼前节缺血综合征的发生.本课题主要是探讨斜视矫正手术多条眼外肌一次完成的方法.方法本组手术均在局麻下进行,结膜下注射2%利多卡因,做肌止端结膜切口,暴露直肌,显微镜下将延直肌走行的睫状前动脉分离出来,离断肌肉时保留血管.手术量和术式与常规眼外肌手术相同.结果斜视矫正效果:治愈32例(88.89%),好转4例(11.11%).采用彩色多普勒测定虹膜大环术前术后血流流速,差异无显著性.结论应用血管分离术可实现多条眼外肌手术一次完成.眼外肌睫状前动脉血管显微分离术最大限度地降低眼前节缺血发生的可能.减少手术次数,既简化了斜视矫治过程又减轻了病人的痛苦.     

银杏叶片对慢性青光眼术后血流动力学影响

目的应用彩色多谱勒成像(CDI)技术,观测慢性青光眼术后眼压已正常者使用银杏叶片后血流动力学的变化.方法对50例(89眼)慢性青光眼抗青光眼术后眼压已正常患者使用银杏叶片和安慰剂3月,用彩色多谱勒超声检查仪测定其眼动脉,视网膜中央动脉和睫状后短动脉的收缩期峰值血流速度(PSV),舒张末期血流速度(EDV),阻力指数(RI)的变化.结果使用银杏叶片3月后,PSV,EDV明显增加,RI明显降低.结论在治疗青光眼降低眼压的同时,使用银杏叶片类的药物可为青光眼视功能的恢复提供新的治疗途径.     

青光眼小梁切除术前后眼部血流动力学变化的研究

目的:比较青光眼32眼小梁切除术前后的血流动力学变化。方法:利用彩色多普勒成像技术(CDI)分别检测正常对照组与青光眼组术前、术后2,12wk的眼部血流情况,包括眼动脉(OA)、睫状后短动脉(SPCA)和视网膜中央动脉(CRA)的收缩期峰值血流速度(PSV)、舒张末期血流速度(EDV)和阻力指数(RI)。结果:(1)青光眼组手术前后比较:青光眼组在小梁切除术后血流灌注明显好转,表现为PSV,EDV增高,RI下降;(2)青光眼术后组之间比较:PSV,EDV,RI有改变,但差异无统计学意义;(3)青光眼组术后与正常对照组比较:青光眼组在小梁切除术后眼压降至正常范围时OA,SPCA,CRA的PSV,EDV和RI仍不及正常人(P<0.05);(4)青光眼组术前与正常对照组比较:OA,SPCA,CRA均表现为PSV,EDV下降,RI增高(P<0.01)。结论:(1)青光眼患者与正常人相比较存在明显的血流灌注不足,小梁切除术可以有效的改善眼部血流灌注情况;(2)CDI可长期用于监测和评价青光眼小梁切除术的治疗效果。     

Hemodynamic changes after strabismus surgery

AIM: The aim of this study was to investigate the hemodynamic changes that may occur in the retrobulbar circulation after strabismus surgery, using color Doppler ultrasonography (CDI). METHODS. Fifteen healthy volunteers (control group, n=15) and sixteen patients diagnosed with strabismus were enrolled in the study. Either recession or resection was planned on one horizontal rectus muscle in the eyes of Group 1 (n=11) and on two horizontal rectus muscles in the eyes of Group 2 (n=10). CDI was performed to measure peak systolic velocity (V max ), end-diastolic velocity (V min ) and mean blood flow velocity (V mean ) in the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) in the control group and in Groups 1 and 2, both preoperatively and 2-7 days postoperatively. RESULTS. The postoperative resistivity indexes in Groups 1 and 2 were found to be different from those in the control group. Preoperative V max and postoperative V min and V mean values of the vessels in Group 2 were different from those in both Group 1 and the control group (p&lt;0.001). In both treatment groups, the differences between postoperative and preoperative measurements of the parameters in the OA, CRA and PCA demonstrated statistical significance (p&lt;0.001). CONCLUSION. After strabismus surgery on the horizontal recti, there are some alterations in the retrobulbar blood flow with a significant difference between pre- and postoperative blood flow velocities after single and double rectus surgery. The clinical significance of these results needs to be determined because CDI may be a useful tool in the investigation of hemodynamic alterations after anterior segment interventions that may cause anterior segment ischemia.     

The effect of strabismus surgery on retrobulbar hemodynamics.

PURPOSE: To investigate the potential alterations of ocular hemodynamics after strabismus surgery using color Doppler ultrasonography. MATERIALS AND METHODS: Twenty eyes of 18 patients and the left eyes of 20 healthy age- and sex-matched volunteers were evaluated. Patients were divided into two groups according to the number of operated muscles. Group 1 included seven patients with surgery on one rectus muscle; group 2 included 13 patients with surgery on two rectus muscles. Nine patients underwent adjustable suture eye muscle surgery. The ophthalmic artery, central retinal artery, short posterior ciliary artery, long posterior ciliary artery, and central retinal veins of both groups were examined. With spectral analysis, peak systolic velocity, end-diastolic velocity, resistivity, and pulsatility indices were calculated. RESULTS: There was no difference in the Doppler ultrasonography parameters between the group with surgery on one-horizontal rectus muscle and the group with surgery on two-horizontal rectus muscles. The adjustable suture procedure did not affect retrobulbar hemodynamics. There was no difference between the preoperative and postoperative Doppler examinations. CONCLUSIONS: In contrast with some recent studies, our results suggest that the strabismus surgery involving one- or two-horizontal rectus muscles does not have a measurable effect on retrobulbar blood flow.     

Investigation of hemodynamic changes after strabismus surgery using color Doppler imaging.

PURPOSE: To investigate hemodynamic changes after strabismus surgery using color Doppler imaging (CDI). METHOD: Group 1 patients (n = 13) underwent surgery on a single horizontal rectus muscle, and group 2 (n = 13) underwent surgery on both horizontal rectus muscles. Subjects with no systemic or ophthalmologic disorders were selected as controls (n = 16). In group 1 and group 2, CDI of the ophthalmic artery (OA), the central retinal artery (CRA), and the nasal and temporal posterior ciliary arteries (PCAs) was performed before surgical correction and on postoperative days 1 and 7. For each vessel, peak systolic (V(max)), end diastolic (V(min)), and mean (V(mean)) blood flow velocities were measured, in addition to the resistivity index (RI) and pulsatility index (PI). RESULTS: V(max) in the OA on postoperative day 1 was higher in group 2 than in group 1 (P =.004). V(min) in the OA on postoperative day 1 was significantly higher in group 2 than in the controls (P =.001) and group 1 (P =.001). For group 2, comparison of the OA preoperative findings to the findings on postoperative day 1 showed that V(min) (P =.003) and V(mean) (P =.02) increased significantly, and the RI (P =.01) and PI (P =.006) decreased significantly. These significant differences were not observed on day 7 (P >.05). CONCLUSION: Surgery on both horizontal rectus muscles in an eye causes hemodynamic changes in the OA in the early postoperative period.     

斜视患者水平直肌离断后眼前房炎症反应的变化

目的：探讨人眼内外直肌分别或同时离断后是否可引起眼前房炎症反应以及影响程度。 方法：回顾性分析水平斜视需行内外直肌手术的患者52例60眼,分为两组,A组30眼为单眼一条水平直肌切断,B组30眼为单眼内外直肌同时切断。每只术眼均在术前及术后第1d行FM-600型激光蛋白细胞检测仪（LFCM）检查,测定前房炎症反应程度。收集被测眼房水闪辉值,每组手术前后数据进行统计学分析。 结果:术前及术后第1d LFCM检测结果显示A组手术前后前房炎症反应变化无统计学意义(P>0.05),B组手术前后前房炎症反应变化有统计学意义(P<0.05),B组术后第1d的房水闪辉值的均值仍在正常范围内。 结论:一条水平直肌切断后并不引起眼前房炎症反应;两条水平直肌同时离断损伤了相应的睫状前动脉,使之供应区域的虹膜睫状体发生缺血而导致功能异常,引起了眼前房轻度的炎症反应;两条水平直肌同时离断后由于有侧支循环的代偿,并不引起严重的眼前节缺血综合征。     

直肌内血管显微分离术方法的实验研究

目的探讨眼直肌内睫状前动脉(ACAs)显微分离术的方法和技巧及应用此方法在一眼同时行4条直肌手术的安全可行性.方法对健康成年杂种犬10只16只眼行直肌内睫状前血管显微分离术.其中8只眼行直肌联结术(Jensen术式),8只眼行肌肉转位术(Hummelsheim术式),术后观察眼前段反应三个月.结果垂直肌的血管较水平肌粗,易分离.ACAs在直肌内的数目存在变异.每例手术均成功分离并保留了大多数ACAs,两种术式术后均未发现眼前节缺血(ASI).结论直肌内血管显微分离术是一种安全可行的显微手术方法,可使累及多条直肌的复杂斜视手术一次完成,避免或减少了ASI的风险.     

Investigation of hemodynamic changes in the ophthalmic artery using color Doppler imaging after strabismus surgery

PURPOSE: We investigated hemodynamic changes in the ophthalmic artery (OA) using color Doppler imaging (CDI) after two horizontal rectus muscles surgery. METHODS: Eyes of the surgical group (n=18) underwent surgery on two horizontal rectus muscles, and the control group was the contralateral eyes. CDI of the OA was performed before operation and on postoperative days (POD) 1, 7 and 30. Peak systolic (Vmax), end diastolic (Vmin), and mean (Vmean) blood flow velocities were measured, and resistivity index (RI) and pulsatility index (PI) were calculated. RESULTS: Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower in the surgical group than in the control group on POD 1 (p<0.05). In the surgical group, Vmax, Vmin and Vmean were significantly higher, and RI and PI were significantly lower, on POD 1 than those measured on other days (p<0.05). CONCLUSIONS: We showed that surgery on the two horizontal rectus muscles increased OA blood flow during the early postoperative period.     

Effect of a modified rectus tuck on anterior ciliary artery perfusion

Strabismus surgery results in the permanent interruption of anterior ciliary blood flow, predisposing the eye to anterior segment ischemia (ASI). A primate model was used to assess the effectiveness of a new muscle-scleral tuck for preserving anterior ciliary artery circulation. The model consisted of removing 3 rectus muscles from both eyes of 2 rhesus monkeys, then performing a tuck on the inferior rectus (IR) right eye while leaving the left IR as a control. Four weeks later, a modified tuck was performed on the virgin left IR. Fluorescein iris angiograms of both eyes were obtained, and preoperative angiograms at 5-15 sec. showed normal 360 degrees perfusion. Postoperative follow-up angiograms showed segmental superior temporal filling defects and preservation of perfusion in the distribution of the IR. Comparison of fellow eyes tucked vs control IR showed no difference in the filling pattern in both monkeys. Comparison of the same eye before and after tuck also showed essentially the same filling pattern in all 4 eyes with preservation of inferior circulation. Our conclusion is that the modified tuck preserves the anterior ciliary blood flow and may be useful as a muscle-strengthening procedure in patients predisposed to developing ASI.     

Color Doppler imaging of the ocular ischemic syndrome.

PURPOSE: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. METHODS: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in study group eyes and in an age-matched control population. RESULTS: We demonstrated markedly reduced ocular ischemic syndrome central retinal and posterior ciliary artery peak systolic velocities compared with control group eyes. Central retinal and posterior ciliary artery vascular resistance (pulsatility index) was greater in ocular ischemic eyes versus control group eyes. Reversal of ophthalmic artery blood flow was detected in 12 of 16 ocular ischemic syndrome eyes. Study group eyes with poor vision had no detectable posterior ciliary arterial blood flow. CONCLUSION: Color Doppler imaging quantitates hemodynamic characteristics of the retrobulbar circulation in the ocular ischemic syndrome. There is markedly reduced peak systolic velocity and increased vascular resistance in ocular end arteries such as the central retinal and posterior ciliary arteries. Ophthalmic artery reversal of flow seems to represent collateral blood flow to lower resistance vascular beds. Posterior ciliary artery hypoperfusion may correlate with poor vision in the ocular ischemic syndrome.     

Anterior ciliary sclerotomy for treatment of presbyopia: a prospective controlled study

PURPOSE: To examine the safety and efficacy of anterior ciliary sclerotomy to restore accommodation in the presbyopic eye. DESIGN: Prospective nonrandomized comparative single-center clinical trial. PARTICIPANTS: Nine presbyopic subjects with no prior ocular surgery except corneal refractive procedures were enrolled. METHODS: One eye from each subject was chosen, in consultation with the patient, to undergo anterior ciliary sclerotomy. The contralateral eye of each subject served as a control. Examinations were performed preoperatively, and at 1 day, 1 week, 1 month, and 6 months after surgery. MAIN OUTCOME MEASURES: (1) Accommodative amplitude, measured by two methods, (2) Jaeger reading vision at 14 inches wearing best distance correction, (3) manifest refraction, (4) assessment of operative complications. RESULTS: For the nine study eyes, there was no statistically significant change between the average accommodative amplitude at the preoperative visit (1.11 diopter [D]) and the 1-month postoperative visit (1.19 D, P = 0.55) nor at the 6-month postoperative visit (1.31 D, P = 0.21) in the study eyes. There was no significant difference between the study and control eyes' change in accommodative amplitude at 6 months (P = 0.43). Logarithm of the minimum angle of resolution equivalent of Jaeger reading vision in the study eyes at 14 inches wearing best distance correction showed no statistically significant change from the preoperative visit (0.53 [20/70]) at the 1-month postoperative visit (0.41 [20/50], P = 0.07) or at the 6-month postoperative visit (0.48 [20/60], P = 0.22). There was no significant change in manifest refraction spherical equivalent in the study eyes at 1 and 6 months postoperatively. One eye experienced a perforation of the anterior chamber during surgery. A second eye experienced mild postoperative anterior segment ischemia manifested by sectoral iris akinesis. CONCLUSIONS: Anterior ciliary sclerotomy does not restore accommodation in presbyopic eyes and can cause significant complications.     

Partial rectus muscle-augmented transpositions in abduction deficiency.

PURPOSE: Lateral posterior fixation sutures increase the effect of full rectus extraocular muscle transpositions. Partial rectus muscle transposition may be indicated to minimize the risk of anterior ischemia when multiple rectus muscles require surgery to achieve ocular alignment. PURPOSE: To report a modification of full vertical rectus muscle transposition with lateral posterior fixation sutures for use in patients at risk for anterior segment ischemia. METHODS: Ten cases of unilateral split rectus muscle transposition augmented with lateral posterior fixation sutures were analyzed. Five patients had Duane's syndrome with esotropia in primary position, and five patients had sixth-nerve palsy. RESULTS: Seven patients had a history of ipsilateral rectus muscle surgery, and three patients underwent simultaneous surgery on ipsilateral horizontal rectus muscles. In Duane's syndrome patients, the preoperative angle of deviation at distance was 15.8 +/- 5.8 prism diopters (PD) (range, 10 to 25) compared with 3.2 +/- 4.4 PD (range, 0 to 8) postoperatively (P =.005). In patients with sixth-nerve palsy, the preoperative angle of deviation at distance was 45.2 +/- 23.9 PD (range, 16 to 80) compared with -5 +/- 14.1 PD (range, -30 to 5) postoperatively (P =.004). Postoperative binocular single visual fields enlarged in seven of seven patients. CONCLUSION: Partial rectus muscle-augmented transposition allows surgery on multiple ipsilateral rectus muscles in (1) Duane's syndrome patients with esotropia, marked cocontraction, and/or limitation to both horizontal rotations and in (2) sixth-nerve palsy patients with ipsilateral medial rectus tightness. Augmented partial rectus muscle transpositions improve ocular alignment and may enlarge binocular single fields in patients with persistent deviations despite previous muscle surgery.