Horizontal and vertical deviations after prism neutralization and diagnostic occlusion in intermittent exotropia

The long-term result of surgery in intermittent exotropia is often an undercorrection and relapse into tropia. This may be due to an underestimation of the horizontal angle and/or an undetected vertical component. The aim of the present study was to test which method, prism neutralization or diagnostic occlusion was best suited to attain the maximal angle of horizontal and vertical deviation. Twenty-two patients with intermittent exotropia but without initial vertical or incomitant components participated in the study. The horizontal deviation was neutralized with prisms for periods of 14 days on four different occasions with diagnostic occlusion three times for periods of one, three or ten days in between. Measurements of sensory functions and the amount of deviations were performed before and after the procedures. It was shown that the largest horizontal deviation was elicited by prism neutralization without previous occlusion and the largest vertical deviation by diagnostic occlusion for ten days. Conditions of initial divergence excess and lateral incomitances usually were restored by both procedures.     

Effects of surgery on the dominant eye in exodeviations

It has been suggested that operating the dominant eye is a more effective way of treatment for exodeviations than the conventional non-dominant eye surgery. We have tested this idea in groups of children and adults with intermittent and constant exotropia. In a first group of 30 patients where the non-dominant eye was operated on, we found that our initial technique resulted in an undercorrection averaging 11 prism diopters. Modification of the technique, by increasing the relative amount of surgery on the non-dominant eye in another group of 41 patients, improved the results significantly in adult patients, but not in children. Operations on the dominant eye in a third group of 26 patients were no more successful than non-dominant eye surgery with the initial technique. Thus, we did not obtain better results in operations on the dominant eye with our technique than we did with surgery on the non-dominant eye.     

间歇性外斜视患者知觉眼位和主观斜视角的比较

目的：通过和同视机主观斜视角比较,了解间歇性外斜视患者知觉眼位的情况和意义。方法：系列病例研究。对2017年2-8月在北京同仁医院的间歇性外斜视患者分别用同视机检测其主观斜视角和用基于计算机平台的视感知觉检查方法检测其知觉眼位,将同时具备以上2项检测结果的患者作为研究对象。对二者水平方向眼位进行线性相关分析;统计同视机主观斜视角在垂直方向眼位偏斜的检出率,对同视机主观斜视角未检出垂直偏斜者分析其垂直知觉眼位的分布情况;对水平和垂直知觉眼位进行线性相关和回归分析。结果：共有120例间歇性外斜视患者被纳入研究。在水平方向,主观斜视角为（-8.1±5.3）°,知觉眼位偏移值为（332±233）像素,同视机主观斜视角越向外偏移,水平方向的知觉眼位偏移越大（r=-0.383,P<0.001）。在垂直方向,3例（2.5%）同视机检测到眼位偏斜,117例未检测出垂直眼位偏斜者中有113例（94.2%）可检测出不同程度的知觉眼位偏差,为（22±29）像素,其中67.5%（81/120）≤26像素（垂直眼位偏斜在0.5°以内）,有82.5%（99/120）≤53像素（垂直眼位偏斜在1°以内）。120例患者垂直方向知觉眼位偏移为（24±32）像素,它与水平方向知觉眼位偏移呈线性相关关系（r=0.373,P<0.001）,线性回归方程为垂直知觉眼位偏移=6.403+0.052×水平知觉眼位偏移（F=19.093,P<0.001）。结论：同视机主观斜视角与知觉眼位偏移均能反映间歇性外斜视患者双眼分视状态下水平方向的眼位偏斜状态;知觉眼位检查在垂直方向的眼位偏斜检出率明显高于同视机;垂直方向的知觉眼位偏斜随着水平方向知觉眼位偏斜的增加而增大。     

外直肌超长量后徙术治疗大角度外斜视的疗效评价

背景 临床上矫正超过50Δ的大角度外斜视时往往需对3条或4条水平直肌进行手术,以避免因外直肌超长量后徙(＞7 mm)引起的眼球外转受限.但研究表明,超长量外直肌后徙可有效矫正大角度外斜视,且术后并不出现眼球明显外转受限.这个结果仍有待临床上进行验证. 目的 观察双眼外直肌超长量后徙或合并非主导眼内直肌缩短对大角度外斜视的矫正效果. 方法 采用系列病例观察法对2013年5月至2014年10月在天津市眼科医院行双眼外直肌超常量后徙术或合并非主导眼内直肌缩短术的间歇性或恒定性大角度外斜视患者51例的治疗效果进行分析,其中29例为间歇性外斜视,22例为恒定性外斜视.所有患者均接受术前及术后眼前节、眼底、眼球运动和双眼视功能检查,采用三棱镜加遮盖法测量斜视角大小.依据病史、眼球运动、知觉状态和斜视角度数对患者行个体化手术治疗,术中结合可调整缝线技术,行双眼外直肌超长量后徙术或合并非主导眼内直肌缩短术.术后随访时间均超过6个月,比较术眼术前和术后眼位变化、眼球运动情况以及双眼知觉功能.结果 行双眼外直肌超长量后徙术者33例,双眼外直肌超长量后徙术合并非主导眼内直肌缩短术者18例.术前患者视远(5 m)斜视度为-52Δ～-120Δ,平均(-70.57±16.46)Δ;视近(33 cm)斜视度为-55Δ～-130Δ,平均(-75.65±16.14)Δ.左眼外直肌后徙8～15 mm,平均(11.17±1.67)mm,右眼外直肌后徙9～15 mm,平均(11.28±1.62) rnm,非主导眼内直肌缩短3～6 mm.末次随访时患者视远斜视度为+4Δ ～-14Δ,平均(-3.45±4.20)Δ;视近斜视度为+4Δ～-14Δ,平均(-5.49±3.96)Δ,其中41例术后眼球正位,占80.4％,10例欠矫,未发现过矫者.32例患者术后立体视较术前改善,其中术前无立体视的27例中18例术后获得不同程度的立体视.无一例患者出现眼球运动障碍.结论 双眼外直肌超长量后徙术或合并非主导眼内直肌缩短术可有效治疗大角度外斜视,可减少需要手术的眼外肌数目,术后未发现眼球运动障碍.     

Surgical outcomes of intermittent exotropia associated with concomitant hypertropia including simulated superior oblique palsy after horizontal muscles surgery only

PURPOSE: To investigate the clinical features and obtain guideline of treatment in intermittent exotropia associated with hypertropia including simulated superior oblique palsy. METHODS: We retrospectively reviewed the charts of 93 patients of intermittent exotropia aligned with horizontal muscle surgery only, who showed hypertropia more than 2 PD in primary gaze before surgery and disappeared after surgery. They showed forveal extorsion and dysfunction of oblique muscles of 2+ or less and positive Bielschowsky head tilt test. The postoperative changes of deviation angle were analysed at postoperative 1 day, 6 months, and 1 year. RESULTS: Average amount of distant horizontal deviation in primary gaze was 32.3+/-9.58 (25-53) PD, hypertropia was 3.50+/-2.52 (2-14) PD. Average vertical deviation of ipsilateral (hypertropic eye) side was 8.8+/-4.63 PD and contralateral (hypotrophic eye) side was 4.0+/-4.77 PD in Bielschowsky head tilt test. Hypertropic eye was accorded with exotropic eye in 53.4%. After horizontal surgery, the amount of hypertropia was 1.2 PD at postoperative 1 day. On Bielschowsky head tilt test, hypertropia was almost eliminated showing 0.6 PD on the ipsilateral side and 0.2 PD on the contralateral eye at 1 month. This state was maintained up to postoperative 1 year. CONCLUSION: Small amount of hypertropia up to 14 PD in intermittent exotropia could be disappeared with horizontal muscle surgery only. However, careful examinations for head tilt history, fovea extorsion, oblique dysfunction, and Maddox rod test should be preceded to rule out true superior oblique palsy.     

同视机法与基于计算机平台的知觉眼位检查法检测间歇性外斜视患者主观斜视角的对比观察

目的 对比分析同视机法与基于计算机平台的知觉眼位检查法检测间歇性外斜视患者的主观斜视角的差别。设计 前瞻性比较性病例系列。研究对象 间歇性外斜视患者355例。方法 用同视机检测患者的远距离主观斜视角,用基于计算机平台的知觉眼位检查方法检测间患者的中距离主观斜视角。主要指标 水平主观斜视角和垂直主观斜视角。结果 同视机检查水平主观斜视角平均值为（-8.85±5.39）°,垂直眼位偏斜平均值为（2.13±1.33）°;知觉眼位检查水平主观斜视角平均值为（287.41±220.80）像素（1°=53像素）,垂直眼位偏斜平均值为（25.06±33.95）像素。水平主观斜视角的检出率,知觉眼位检查（84.79%,301/355）高于同视机检查（63.10%,224/355）（χ2=51.115,P=0.000）;垂直眼位偏斜的检出率,知觉眼位检查（82.82%,294/355）高于同视机检查（6.44%,23/355）（χ2=267.033,P=0.000）。同视机检查23例存在垂直眼位偏斜的患者,其水平主观斜视角为（-10.48±3.19）°,其垂直主观斜视角为（2.13±1.33）°,两者之间不呈线性相关（r=-0.211,P=0.335）。知觉眼位检查294例存在垂直眼位偏斜的患者,其水平主观斜视角为（291.05±220.43）像素,垂直主观斜视角为（25.06±33.95）像素,两者之间呈线性相关（r=0.406,P=0.000）。206例患者两种方法同时检测出了水平主观斜视角,同视机检查为（-8.84±5.31）°,知觉眼位检查为（296.14±222.19）像素,两者之间呈线性相关（r=-0.301,P=0.000）。22例用两种方法同时检测出垂直眼位偏斜,同视机检查为（2.09±1.34）°,知觉眼位检查为（42.95±40.88）像素,两者之间不具有线性相关关系（r=0.119,P=0.598）。结论 在间歇性外斜视患者中,同视机法与知觉眼位主观斜视角检查法均能反映患者双眼分视状态下水平方向的眼位偏斜状态;知觉眼位检查法在垂直方向的眼位偏斜检出率明显高于同视机法;垂直方向的知觉眼位偏斜随着水平方向知觉眼位偏斜的增加而增大。知觉眼位检查法是一种更灵敏精确地反映间歇性外斜视患者眼位偏斜状态的检查方法。（眼科, 2020, 29： 133-137）     

Predictors of postoperative binocularity in adult strabismus

We evaluated postoperative binocularity in a retrospective study of 111 adult strabismus patients in order to identify the factors which influence the success of surgery for horizontal concomitant strabismus in adults. Selection criteria included minimum age of 15 years at time of surgery, and preoperative fusion impairment with both the Bagolini lens test and synoptophore. Logistic regression analysis was used to correlate patient factors and postoperative binocularity. We found that 52 (65%) of 80 patients with exotropia and 23 (74.2%) of 31 patients with esotropia achieved post operative fusion. Significant predictive factors in exotropia were absence of previous surgery; visual acuity of the deviating eye >0.5; an increase in the spherical equivalent of the deviating eye, and normal retinal correspondence. Significant predictive factors in esotropia were fusion during prism adaptation, absence of infantile esotropia, and an increase in vertical deviation. The majority of adults with exotropia or esotropia can achieve binocularity after surgery for horizontal concomitant strabismus.     

Conversion of intermittent exotropia types subsequent to part-time occlusion therapy and its sustainability

Purpose To evaluate the effects of part-time occlusion therapy on types of intermittent exotropia and sustainability of converted types.Methods Forty-four and 26 children with basic-type and convergence-insufficiency-type intermittent exotropia, respectively, were evaluated in this study. Upon initial examination, we obtained both distant and near deviating angles using prism cover tests, after correcting for refractive errors. We conducted occlusion of the nondeviating eye for 3 months at 3 h/day and assessed the changes in types of intermittent exotropia. We also observed the changes of deviating angles and sustainability of types after 3 months of cessation of part-time occlusion in patients who did not undergo surgery.Results Preocclusion deviating angles (mean ± SD) were determined to be 27.1±7.46 prism diopters (PD) on distant measurements and 30.6±7.92 PD on near measurements. After 3 months of occlusion, the deviating angles were 25.9±9.10 PD on distant measurements and 21.4±11.00 PD on near measurements, corresponding to a significant reduction (p=0.005 and p<0.001, respectively). Fourteen patients (32%) suffering from basic type of intermittent exotropia converted to the pseudodivergence excess type. In patients suffering from the basic type who exhibited no changes in type, 9 patients (20%) exhibited reductions on both near and distant angle measurements. Among the convergence insufficiency type of patients, 18 (69%) converted to basic type and 2 patients (7%) converted to the pseudodivergence excess type. In the 15 patients who did not undergo surgery, the converted types were maintained in 6 patients, though the other 9 patients showed regression to the prepatching types after cessation of patching for 3 months.Conclusion Part-time occlusion therapy resulted in the conversion of the basic and convergence insufficiency types to pseudodivergence excess and basic types in more than half of the intermittent exotropes. Future studies on correlation between type conversion and surgical outcome would be necessary.     

Bilateral Occlusion Reduces the Ocular Deviation in Intermittent Exotropia

PurposeThe most common form of strabismus, intermittent exotropia, is thought to become manifest when the drive to fuse is overcome by excessive divergent muscle tone. This principle is tested by examining the alignment of the eyes in the absence of vision. We compare the ocular deviation in patients with intermittent exotropia under conditions of monocular versus binocular occlusion.MethodsThis prospective study of a patient cohort referred to our laboratory enrolled 18 patients with typical findings of well-controlled intermittent exotropia. Eye positions were recorded with video eye trackers while patients looked at a fixation spot at a distance of 57 cm. One eye was occluded, and the resulting ocular deviation was measured. Both eyes were then occluded, and the ocular deviation was re-measured.ResultsThe majority of patients (11/18) had a smaller deviation when both eyes were covered. Occlusion of one eye resulted in a mean exotropia of 13.5° ± 4.7°. Occlusion of both eyes reduced the mean exotropia to 6.0° ± 6.5° (paired t-test, P < 0.001), corresponding to a 56% reduction in the ocular deviation. This reduction persisted during prolonged bilateral occlusion but reversed as soon as vision was restored.ConclusionsBilateral occlusion reveals a fixation-free state of alignment that is different from orthotropia and usually less than the exotropia that occurs spontaneously during binocular viewing. This finding demonstrates that the deviation angle in patients with intermittent exotropia is actively mediated by visual feedback, which the fixating eye is capable of providing alone.     

A topographical survey of the insertions of horizontal recti in strabismus

The distance to the limbus and breadth of the insertions of the horizontal recti were measured in 857 strabismic patients during operation. The average distance and breadth of MR were 4.99 mm and 10.02 mm, and those of the LR were 6.48 mm and 9.47 mm respectively. The insertion of MR in esotropia (4.87 mm) was nearer to the limbus than that in exotropia (5.39 mm) (P less than 0.01). The insertion of LR in esotropia (6.66 mm) was further from the limbus than that in exotropia (6.43 mm) (P less than 0.01). The relationships between the horizontal recti insertion and the degree of deviation and the refraction of the deviating eye were discussed. It was inferred that the position of the insertion could play a role in the etiology of strabismus.     

Effects of unilateral lateral rectus recession according to the tendon width in intermittent exotropia

PURPOSE: To verify the effect of unilateral lateral rectus recession for each millimeter according to the tendon width in intermittent exotropia. METHODS: A total of 37 patients (37 eyes) of 7 to 11 years of age with basic-type intermittent exotropia and a deviation of 16-25 Prism Diopters (PD) were included in this study. Under general anaesthesia, the tendon width of the lateral rectus of the deviating eye near insertion was measured with calipers, prior to dissection of the muscle tendon from the sclera. Patients underwent 6.5-10 mm unilateral lateral rectus recession. The effect of lateral recession for each millimeter was the absolute value of the angle of preoperative deviation plus postoperative deviation on the second day divided by the total amount of recession. RESULTS: Mean tendon width of the lateral rectus of a deviating eye was 8.3 mm (range: 6.5-9.5). The mean effect per millimeter of unilateral rectus recession in those 37 patient was 2.98+/-0.42 PD (range: 2.4-4.1). The effect of recession was larger in cases in which the tendon width of the lateral rectus was narrower (P=0.000, r=0.72). CONCLUSION: The tendon width of the lateral rectus muscle can be a useful indicator to estimate the effect of lateral rectus recession in intermittent exotropia.     

Binocular function of intermittent exotropia before and after surgery

PURPOSE: We examined the binocular function of intermittent exotropia before and after surgery, and studied the effect of the surgery and the factor that might be involved in its result. MATERIALS AND METHODS: 402 intermittent exotropic patients, who underwent their first surgical correction for the strabismus at Teikyo University Hospital, were examined for retinal correspondence and stereo acuity before and after surgery. RESULTS: 367 patients (91.3%) had already had good stereo acuity before surgery when their eyes were straight. Regarding retinal correspondence, though 192 patients (47.8%) were abnormal (dual) before surgery, 301 patients (74.9%) were normal after surgery. The eye deviation of 101 patients who could not get normal retinal correspondence after surgery was significantly larger than normal (p < 0.001), and 77.2% of them had also vertical strabismus which was mainly composed of dissociated vertical deviation. CONCLUSION: Normal binocular function could be recovered by surgical treatment in most intermittent exotropic patients. When patients could not get normal retinal correspondence after surgery, we supposed that dissociated vertical deviation might exert an important effect upon their binocular function.     

Binocular Function of Intermittent Exotropia Before and After Surgery

Purpose: We examined the binocular function of intermittent exotropia before and after surgery, and studied the effect of the surgery and the factor that might be involved in its result.Materials and Methods: 402 intermittent exotropic patients, who underwent their first surgical correction for the strabismus at Teikyo University Hospital, were examined for retinal correspondence and stereo acuity before and after surgery.Results: 367 patients (91.3%) had already had good stereo acuity before surgery when their eyes were straight. Regarding retinal correspondence, though 192 patients (47.8%) were abnormal (dual) before surgery, 301 patients (74.9%) were normal after surgery. The eye deviation of 101 patients who could not get normal retinal correspondence after surgery was significantly larger than normal (P <.001), and 77.2% of them had also vertical strabismus which was mainly composed of dissociated vertical deviation.Conclusion: Normal binocular function could be recovered by surgical treatment in most intermittent exotropic patients. When patients could not get normal retinal correspondence after surgery, we supposed that dissociated vertical deviation might exert an important effect upon their binocular function.     

间歇性外斜视的调节灵活度和调节反应

目的：比较间歇性外斜视和正常眼位人群之间,间歇性外斜视注视眼和非注视眼之间的调节灵活度和调节反应。方法：病例对照研究。选取2016年10月至2017年1月在温州医科大学附属眼视光医院门诊就诊的35例间歇性外斜视患者作为间歇性外斜视组,另选取24例正位眼或外隐斜斜视度≤6 △ 的门诊患者作为对照组。采用±2.00 D的反转拍和开放视野式自动验光仪分别测量受试者在单眼和双眼注视近距视标时的调节灵活度和调节反应。采用t检验对数据进行分析。结果：间歇性外斜视组的双眼调节灵活度为（8.8±4.1）cpm,显著低于对照组[（10.9±3.1）cpm],两者差异有统计学意义（t=-2.165,P=0.035）。间歇性外斜视组的非注视眼调节灵活度显著低于注视眼（t=4.657,P<0.001）。双眼注视40 cm处视标时,间歇性外斜视组的注视眼调节反应高于对照组的主导眼（t=-2.163,P=0.035）。双眼注视状态下,间歇性外斜视组注视眼的调节反应为（1.89±0.30）D,高于其在单眼注视状态下的调节反应[ （1.64±0.34）D],两者差异有统计学意义（t=3.801,P=0.001）。结论：间歇性外斜视患者的双眼调节灵活度低于对照人群,其注视眼和非注视眼的调节灵活度和调节反应均不一致,且双眼注视时调节反应高于单眼注视状态。     

对水平斜视合并小度数垂直斜视患者术后垂直眼位变化的探讨

目的：探讨水平斜视合并小度数垂直斜视患者术后垂直眼位的变化。方法回顾性分析本院2013年6月至2014年6月收治的48例（68只眼）术前水平斜视合并小度数垂直斜视患者的临床资料,其中内斜视22例（32只眼）,外斜视26例（36只眼）,患者均行缩短及水平后徒手术,未行垂直肌及水平肌垂直移位手术。术后对患者随访6～12个月,观察垂直眼位的变化。结果内斜视患者术前平均垂直斜视角为（7．10±2．12）°,术后平均垂直斜视角为（3．45±1．24）°,垂直斜视角减少量为（3．82±1．04）°,手术前后垂直斜角比较有统计学意义（ P ＜0.05）。外斜视患者术前平均垂直斜视角为（7．05±2．09）°,术后平均垂直斜视角为（2．52±1．22）°,垂直斜视角减少量为（4．52±1．12）°,手术前后垂直斜角比较有统计学意义（ P ＜0.05）。内外斜视患者术后垂直斜角减少量与术前垂直斜角大小均呈正相关（ P ＜0.05）。内、外斜视患者术前黄斑中心凹与视盘几何中心相对角度（ FDA）手术前后比较均无统计学差异（ P ＞0.05）。结论水平斜视合并小度数垂直斜视患者行水平肌手术治疗后能改善垂直眼位,且改善效果与患者术前垂直斜视角呈正相关。     

Changes in Exodeviation after the Monocular Occlusion Test in Adult Patients with Intermittent Exotropia and Its Association with the Level of Control

PurposeWe investigated the changes in ocular deviation after the monocular occlusion test in adults with intermittent exotropia and evaluated its association with the level of control.MethodsWe retrospectively enrolled adults (aged ≥18 years) with intermittent exotropia who visited our clinic between September 2015 and May 2019. Patients with basic intermittent exotropia with a distant deviation within 10 prism diopters (PD) of the near deviation were included. The largest ocular deviations obtained before and after 1 hour of monocular occlusion were compared. The level of control was measured using the LACTOSE (Look and Cover, then Ten seconds of Observation Scale for Exotropia) control scoring system.ResultsForty-six consecutive adult patients (28 males, 18 females; mean age, 34.3 years) were enrolled. The mean ocular deviation was 36.3 PD (range, 18 to 5 PD) at distant fixation and 38.5 PD (range, 18 to 80 PD) at near fixation, which increased significantly to 38.5 PD (p = 0.043) and 41.1 PD (p = 0.011), respectively, after monocular occlusion. The mean ocular deviation increased ≥5 PD in 14 (30.4%) and 15 (32.6%) patients at distant and near fixation, respectively. The level of control was measured in 30 patients. A higher degree of near control was significantly associated with an increase of ≥5 PD in near fixation after the test (p = 0.009 for a near control score ≤2).ConclusionsThe monocular occlusion test may help to determine the largest ocular deviation in adults with intermittent exotropia. Approximately one-third of patients exhibited an increase in ocular deviation ≥5 PD. Patients exhibiting good control were more likely to manifest an increase in the ocular deviation.     

The value of the occlusion test in decompensating exophorias and intermittent exotropias

The importance of the occlusion test is analysed in patients who were operated for a decompensating exophoria or an intermittent exotropia. Of particular interest before and after the occlusion test was the number of the following variables: the distant angle, the near angle, the difference between these two (the so-called distant angle-near angle difference), and the angle at right respective left gaze. All patients included in this study had been examined at least three times preoperatively. The occlusion test was performed in all patients by occluding one eye on three consecutive days. A total of 36 patients with decompensating exophoria and 33 patients with intermittent exotropia were included in this retrospective clinical trial. Only the near angles of the patients with the decompensating exophorias demonstrated a statistically significant increase. All the other angles did not show a significant change. In contrast to what might have been expected, the difference between the distant angle and the near angle increased in the exophoria group. This was not the case in patients with intermittent exotropia. Thus the occlusion test cannot generally be recommended as an obligatory part of the preoperative diagnostics in patients with exophoria or intermittent exotropia. In selected cases it may however be worthwhile to decide on the exact extent of the operation planned.     

Effects of diagnostic occlusion on ocular alignment in normal subjects

Diagnostic occlusion is used in strabismus to examine the changes in the angle of squint after a period of disrupted fusion. The aim of the present study was to investigate the effect of diagnostic occlusion on ocular alignment in normal subjects without strabismus and other ocular motility related symptoms. Diagnostic occlusion of the non-dominant eye was applied to ten subjects for three days. In all cases a small horizontal deviation was seen in the primary position and in three cases also a small vertical deviation was noted. Diagnostic occlusion for seven days was applied in nine persons. Changes in alignment of approximately the same size as after three days of occlusion were seen. In both groups incomitances of ocular alignment were noted that indicate small muscle imbalances particularly in the oblique muscles of normal subjects that are easily compensated by normal motor fusion.     

The value of the occlusion test in decompensating exophorias and intermittent exotropias

The importance of the occlusion test is analysed in patients who were operated for a decompensating exophoria or an intermittent exotropia. Of particular interest before and after the occlusion test was the number of the following variables: the distant angle, the near angle, the difference between these two (the so-called distant angle-near angle difference), and the angle at right respective left gaze.

All patients included in this study had been examined at least three times preoperatively. The occlusion test was performed in all patients by occluding one eye on three consecutive days. A total of 36 patients with decompensating exophoria and 33 patients with intermittent exotropia were included in this retrospective clinical trial.

Only the near angles of the patients with the decompensating exophorias demonstrated a statistically significant increase. All the other angles did not show a significant change. In contrast to what might have been expected, the difference between the distant angle and the near angle increased in the exophoria group. This was not the case in patients with intermittent exotropia.

Thus the occlusion test cannot generally be recommended as an obligatory part of the preoperative diagnostics in patients with exophoria or intermittent exotropia. In selected cases it may however be worthwhile to decide on the exact extent of the operation planned.     

计算机辅助儿童斜视客观检查方法在先天性外斜视早期手术中的应用

【摘要】目的探讨利用计算机辅助方法对先天性外斜视进行早期诊断与治疗的可行性。方法利用计算机辅助斜视客观检查方法，对18例先天性外斜视患者进行了早期的定性与定量诊断，并对所有患者进行了手术治疗，分析其疗效。结果单纯先天性外斜视者14例，合并分离性垂直偏斜（dissociated vertical deviation，DVD）者4例，其中同时合并DVD与上斜肌麻痹者1例。经过早期手术，18例患者中17例获得了眼轴的正位。结论先天性外斜视合并DVD多见。其手术方式，水平斜视者采用双眼外直肌后退，合并DVD者采用上直肌后退。计算机辅助的客观斜视定量检查方法有助于先天性外斜视的早期诊断与早期手术。