Resection and Transposition of the Inferior Oblique for Hypertropia due to the Inferior Rectus Loss

PURPOSE: To report a case of resection and transposition of the inferior oblique muscle combined with superior rectus recession as treatment for large-angle hypertropia due to unilateral loss of the inferior rectus muscle. CASE SUMMARY: A 39-year-old man presented with a complaint of left hypertropia and vertical diplopia caused by blunt trauma 20 years previously. Left hypertropia of 70 prism diopters (PD) and exotropia of 16 PD in the primary gaze were noted; ocular movements of the left eye showed overactive supraduction (+4) and underactive infraduction (−5). On surgical exploration, neither the inferior rectus muscle nor capsule were present at the insertion site. The patient was diagnosed with loss of the inferior rectus muscle, thus, 7 mm of the inferior oblique muscle was resected and transposed at the original insertion site of the inferior rectus muscle; the superior rectus muscle was then recessed by 4.5 mm. After the surgery, vertical alignment was straight in the primary position, infraduction limitation was changed from −5 preoperative to −2 postoperative, and supraduction was changed from +4 preoperative to −2 postoperative. CONCLUSIONS: Extensive resection and transposition of the inferior oblique muscle combined with recession of the superior rectus may help in obtaining a successful surgical outcome in patients with inferior rectus muscle loss with a large angle of vertical deviation.

Anterior transposition of inferior oblique muscle with unequal excision for segregated vertical strabismus with asymmetric inferior oblique hyperfunction / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore the application of anterior transposition of inferior oblique muscle with unequal excision in treatment of segregated vertical strabismus with asymmetric inferior oblique hyperfunction.<p>METHODS: A total of 22 patients(10 males and 12 females, 28 eyes in all)who underwent anterior transposition of the unequal excisional inferior oblique muscle for dissociated vertical deviation with asymmetric inferior oblique muscle overaction were studied retrospectively. The patients were admitted from June 2015 to June 2017,with mean age at 12.32±6.81 years old(ranging from 3 to 28 years old). The binocular vision, the curative effect of DVD, the curative effect of inferior oblique muscle overaction, eye position and compensatory head posture, complications were examined postoperatively, follow-up survey was conducted at 6 to 18mo, meanly at 10.05±3.87mo.<p>RESULTS: Recovery of binocular vision: 11 cases did not have binocular vision(50%); 6 cases recovered to the first level of binocular vision(27%); 3 cases recovered to the second level of binocular vision(14%); 2 cases recovered to the third level of binocular vision(9%). The curative effect of DVD shows: 17 cases with satisfaction(77%), 5 cases with improvement(23%), and 0 case with no avail. The curative effect of inferior oblique muscle overaction shows: 13 cases with cured(59%), 9 cases with improvement(41%), and 0 case with no avail. Postoperative eye position and compensatory head posture: 1)Horizontal eye position: 1 case of under correction after exotropia correction surgery, 1 case of under correction after esotropia correction surgery, 0 case of overcorrection, 20 cases of correction; 2)Vertical eye position: 13 cases show vertical strabism deviation less than 5△, 9 cases show vertical strabism deviation between 5△ to 10△ meanly at 5.55△±2.35△, vertical eye position without overcorrection; 3)Compensatory head posture: 6 cases were disappeared, 1 case was improved. Complications: Mild anti-elevation syndromeoccurred in 1 case, narrowed palpebral fissueoccurred in 1 case, and narrowed quantity less than 1mm.<p>CONCLUSION: In general, the curative effect of anterior transposition of the unequal excisional inferior oblique muscle for dissociated vertical deviation with asymmetric inferior oblique muscle overactionis satisfactory, standard preoperative examination, individualized surgical design and surgical techniques are necessary.

Transient Inferior Oblique Muscle Palsy Following Transconjunctival Lower Lid Blepharoplasty / 고신대학교의과대학학술지

Although the inferior oblique (IO) muscle is positioned considerably deep in the orbit, transconjunctival lower lid blepharoplasty may affect it and transient or permanent IO muscle palsy might result. Therefore diplopia should be explained before cosmetic blepharoplasty performed with transconjunctival approach.

Effect of modified inferior oblique anterior transposition on dissociated vertical strabismus patients with inferior oblique muscle hyperfunction / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the effect of anterior transposition of inferior oblique muscle on the treatment of dissociated vertical deviation(DVD)in children with inferior oblique overaction(IOOA)and unequal inferior oblique transposition of the treatment of IOOA with the eyes of the asymmetry of DVD efficacy, associated with the lower oblique hyperfunction DVD patients to provide more effective treatment. <p>METHODS: Eighty patients with hyperfunction who were treated in our hospital from January 2014 to December 2015 were randomly selected and treated with anterior transposition of inferior oblique muscle. Patients were followed up for 1 to 30mo. We compared the vertical incline at the original incline from far(5m), near(33cm)distance and IOOA degree before and after operations, and the correlation between the two. We also compared the vertical incline at the original incline from far(5m), near(33cm)distance and IOOA degree before and after operations in 30 eyes(20 patients)with bilateral asymmetry DVD and IOOA who received unequal inferior oblique transposition. The incidence of antielevation syndrome(AES)was observed after operations. <p>RESULTS: The mean prism diopters(PD)at 5m before operations was 19.5±0.15, the average PD after operations was 3.5±0.18, at 5m the original incline was 16±0.21PD. The mean PD at 33cm was 18.6±0.20 before operation, 4.5±0.26 after operations, and 14.1±0.16 at 33cm the original incline, the difference was statistically significant(<i>P</i><0.05). Preoperatively, inferior oblique muscle hyperfunction +2 and +3 was 50 eyes, + 1 was 20 eyes, and 12 eyes still showed inferior oblique muscle hyperfunction after operation, but the degree of hyperactivity was +1. There was a significant positive correlation between the degree of IOOA and the vertical inclination(33cm: <i>r</i>=0.554, <i>P</i><0.01; 5m: <i>r</i>=0.454, <i>P</i> <0.01). There were significant differences(<i>P</i><0.05)in the vertical incline in 20 patients(30 eyes)with bilateral asymmetry DVD and IOOA and the degree of IOOA was significantly lower. In contrast, 18 patients(24 eyes)underwent anterior transposition of the inferior oblique muscle had AES in different degrees, which had statistically significant difference(<i>P</i><0.05)compared with patients(30 eyes)with IOOA treated with unequal inferior oblique transposition. <p>CONCLUSION: Anterior transposition of the inferior oblique muscle has a good therapeutic effect on isolated vertical strabismus patients with inferior oblique hyperfunction. While the incidence of postoperative AES is low in patients received unequal inferior oblique muscle transposition.

A Valid Indication and the Effect of Bilateral Inferior Oblique Transposition on Recurrent or Consecutive Horizontal Deviation in Infantile Strabismus

PURPOSE: To evaluate the effects of bilateral inferior oblique transposition (BIOT) on horizontal deviation from primary position among patients with bilateral dissociated vertical deviation (DVD) associated with inferior oblique overaction (IOOA) in infantile strabismus. METHODS: Retrospective chart review was conducted among 19 patients with infantile strabismus. All patients had DVD and IOOA with consecutive or recurrent horizontal deviation and underwent modified BIOT surgery. Patients were divided into three subgroups: patients who underwent BIOT (BIOT group, n = 9) alone, BIOT with medial rectus recession or lateral rectus resection simultaneously (ET BIOT group, n = 6), or BIOT with lateral rectus recession or medial rectus resection simultaneously (XT BIOT group, n = 4). Postoperative angle of horizontal deviation (prism diopter, PD) and corrected magnitude of horizontal deviation (PD) at final visit after surgery were analyzed in each group. RESULTS: The mean age was 55.11 ± 21.05 months (range, 32 to 115). The mean follow-up period was 8.68 ± 2.87 months (range, 6 to 18). Preoperative horizontal deviation was 4.23 ± 5.99 PD (range, 0 to 16) in BIOT, −17.33 ± 6.76 PD (range, −30 to −10) in ET BIOT, and 17.50 ± 2.52 PD (range, 14 to 20) in XT BIOT. Esodeviation is represented by negative values. DVD and IOOA were reduced less than +1 in all patients. The corrected amount of horizontal deviation was 3.56 ± 5.18 PD (range, 0 to 16) in BIOT surgery alone and larger in XT BIOT (18.50 ± 3.41 PD) than in ET BIOT (12.33 ± 5.57 PD, p = 0.004). CONCLUSIONS: Minimal exodeviation was corrected by BIOT alone. In addition, secondary eso- or exodeviation at great magnitudes should be corrected with proper horizontal muscle surgery along with BIOT.

Comparison of Astigmatism Induced by Combined Inferior Oblique Anterior Transposition Procedure and Lateral Rectus Recession Alone

PURPOSE: The purpose of this study is to compare the magnitude and axis of astigmatism induced by a combined inferior oblique (IO) anterior transposition procedure with lateral rectus (LR) recession versus LR recession alone. METHODS: Forty-six patients were retrospectively analyzed. The subjects were divided into two groups: those having concurrent inferior oblique muscle overaction (IOOA) and intermittent exotropia (group 1, 20 patients) and those having only intermittent exotropia as a control (group 2, 26 patients). Group 1 underwent combined anterior transposition of IO with LR recession and group 2 underwent LR recession alone. Induced astigmatism was defined as the difference between preoperative and postoperative astigmatism using double-angle vector analysis. Cylinder power, axis of induced astigmatism, and spherical equivalent were analyzed at 1 week, 1 month, and 3 months after surgery. RESULTS: Larger changes in the axis of induced astigmatism were observed in group 1, with 4.5° incyclotorsion, than in group 2 at 1 week after surgery (axis, 84.5° vs. 91°; p < 0.001). However, there was no statistically significant inter-group difference thereafter. Relaxation and rapid regression in the incyclotorsion of induced astigmatism were observed over-time. Spherical equivalent significantly decreased postoperatively at 1 month in both groups, indicating a myopic shift (p = 0.011 for group 1 and p = 0.019 for group 2) but did not show significant differences at 3 months after surgery (p = 0.107 for group 1 and p = 0.760 for group 2). CONCLUSIONS: Combined IO anterior transposition procedures caused an increased change in the axis of induced astigmatism, including temporary incyclotorsion, during the first week after surgery. However, this significant difference was not maintained thereafter. Thus, combined IO surgery with LR recession does not seem to produce a sustained astigmatic change, which can be a potential risk factor of postoperative amblyopia or diplopia compared with LR recession alone.

Muscular expression of myogenin in V-pattern exotropia with inferior oblique overaction patients / 国际眼科杂志(Guoji Yanke Zazhi)

Abstract?AlM: To study the number of myogenin - positive activated satellite cells in the inferior oblique muscles and the medial muscles of V- pattern exotropia with inferior oblique overaction, to further explore the possible etiological factors of V-pattern exotropia with inferior oblique overaction.? METHODS: The inferior oblique muscles and the medial muscles were cut from V - pattern exotropia patients with inferior oblique overaction during strabismus operation treated as the strabismus group. Cross sections were stained immunohistochemically for the presence of activated satellite cells, as identified by myogenin immunoreactivity. The inferior oblique muscles and the medial muscles were obtained from the corneal transplant donors ( six eyes of six cases) , which treated as the control group.? RESULTS: The frequency of myogenin - positive satellite cells of the inferior oblique muscles was (22. 7± 7.03)% and (4. 2±0. 75)% in the strabismus group and the control group. Significant differences existed in the expression of myogenin in two groups (P<0. 05). Again, the frequency of myogenin-positive satellite cells of the medial muscles was (2. 2±0. 75)% and (4. 5±1. 05)% in the strabismus group and the control group. Significant differences also existed in the expression of myogenin in two groups (P<0. 05).?CONCLUSlON: lt is first report that myogenin-positive satellite cells presents in extraocular muscles of V -pattern exotropia with inferior oblique overaction. The current results suggest that myogenin is one of possible etiological factors of V-pattern exotropia with inferior oblique overaction.

Contralateral Inferior Oblique Muscle Overaction after Unilateral Inferior Oblique Weakening Procedures

PURPOSE: To investigate the effect of unilateral inferior oblique weakening procedures on contralateral inferior oblique muscle functions and factors that may have an effect on contralateral inferior oblique muscle overaction (IOOA). METHODS: A retrospective chart review was conducted of medical records of 40 patients who underwent unilateral inferior oblique (IO) muscle weakening procedures from 2007 to 2011 and were observed during a follow-up period of more than 6 months. These patients were composed of primary IOOA (4 patients), secondary IOOA due to superior oblique muscle (SO) palsy (21 patients), secondary IOOA due to inferior rectus muscle palsy (1 patient), and dissociated vertical deviation (DVD) accompanied with IOOA (14 patients). Factors that may have an effect on contralateral IOOA after undergoing the operation were assessed. RESULTS: There were 7 patients (17.5%) who had over +2 IOOA after operation. IOOA on contralateral eye was increased from average of +0.00 to average of +0.66 +/- 0.14 in 6 months after operation (p < 0.01). There were no statistically significant differences between preoperative factors and functional changes in contralateral IO muscle. CONCLUSIONS: There were no statistical factors that may have an effect on contralateral IOOA but the possibility of masked SO palsy before performing unilateral IO weakening procedures should be considered. In patients who have unilateral DVD associated with IOOA or small hypertropia, the contralateral IOOA can be more definite after operation; thus caution should be taken before operation.

The Effect of Inferior Oblique Muscle Transposition in Primary and Secondary Inferior Oblique Muscle Overaction

PURPOSE: To evaluate and compare the effect of transposition of inferior oblique muscle in patients with primary inferior oblique muscle overaction and secondary due to superior oblique muscle palsy. METHODS: The present study included 41 patients (53 eyes), who appeared to have primary or secondary inferior oblique muscle overaction due to superior oblique muscle palsy and received transposition of inferior oblique muscle with at least 3 months of follow-up. Patients were retrospectively analyzed to compare the effect of correction and its prognosis. Inferior oblique muscle overaction was graded as +1 to +4 according to the severity. Successful surgery was defined as postoperative inferior oblique muscle overaction from 0 to +1 and failure as above +2. Hypertropia in primary gaze was also recorded to evaluate the effect of correction. RESULTS: Twenty-six (35 eyes) and 15 (18 eyes) patients with primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy, respectively, received transposition of inferior oblique muscle. Patients with primary inferior oblique muscle overaction showed correction of 2.1 +/- 0.9 with preoperative inferior oblique muscle overaction of 2.0 +/- 0.7. Patients with secondary inferior oblique muscle overaction showed a correction of 2.3 +/- 0.9 with preoperative value of 2.3 +/- 0.8. Each 3.2 +/- 4.1 prism diopters (PD) and 6.5 +/- 5.3 PD of hypertropia at primary gaze showed correction of 3.0 +/- 7.4 PD and 6.3 +/- 5.1 PD, respectively, in each group. CONCLUSIONS: Primary and secondary inferior oblique muscle overaction due to superior oblique muscle palsy showed no difference in correction of overaction and hypertropia after transposition of inferior oblique muscle. Except for presence of inferior oblique muscle underaction, the correction appears effective with good prognosis.

Evaluation of macular thickness change after inferior oblique muscle recession surgery.

Purpose: This study aimed to evaluate the changes in macular thickness following inferior oblique muscle recession surgery. Materials and Methods: Thirty‑eight eyes from 21 patients undergoing ocular muscle surgery were included. Patients were grouped into three groups based on the type of surgical intervention: Group I (n = 12), inferior oblique recession surgery alone; Group II (n = 12), inferior oblique plus horizontal muscle surgery; Group III (n = 14), horizontal muscle surgery alone. Each eye was scanned using the optical coherence tomography (OCT) device preoperatively and on the first postoperative day to measure macular thickness. Results: Following surgery, a significant increase in foveal thickness occurred in Group I (P < 0.05) and Group II (P < 0.01). In addition, a statistically significant difference was observed between the groups with regard to the increase in foveal thickness (P = 0.016), with significantly lower changes in Group III. Conclusion: Our findings suggested that inferior oblique muscle recession surgery is associated with an increase in macular thickness.

Contralateral Inferior Oblique Overaction after Inferior Oblique Recession in Unilateral Moderate Primary Inferior Oblique Overaction

PURPOSE: To investigate the incidence rate of inferior oblique muscle overaction (IOOA) in the contralateral eye and the effect of inferior oblique (IO) muscle recession of the contralateral eye in the patients who received IO muscle recession for unilateral moderate (+2 or +3) primary IOOA. METHODS: Medical records of 88 patients with unilateral primary IOOA who underwent unilateral IO muscle recession were retrospectively reviewed and observed during a follow-up period of more than 1 year. Graded recession of the IO muscle was performed according to the degree of IOOA. If postoperative IOOA was below +1, the surgery was considered successful. If IOOA in the contralateral eye was more than +2 after surgery, the IOOA was considered to have occurred. RESULTS: In cases where IOOA was +2 and +3 before the surgery, the success rate was 98.2% and 100%, respectively, showing an overall success rate of 98.8%. The incidence of contralateral IOOA after recession of the unilateral IO muscle was 24.1% in the +2 group and 16.6% in the +3 group with an overall incidence rate of 21.6% and when the IO muscle recession of the contralateral eye was performed, the success rate was 100%. CONCLUSIONS: The incidence of contralateral IOOA was 21.6% after the unilateral IO muscle recession in moderate unilateral primary IOOA. A satisfactory outcome was obtained through an additional IO muscle recession in the contralateral eye.

Evaluation of anterior transposition of the inferior oblique muscle with and without resection in the treatment of dissociated vertical deviation / 中国医师进修杂志

Objective To assess the clinical effect of anterior transposition of the inferior oblique muscle (ATTO) with and without resection in the treatment of dissociated vertical deviation (DVD). Methods Thirty-six patients ( 59 eyes ) with DVD were divided into the standard group ( 30 eyes) and the resection group (29 eyes) by random digits table undertaking ATIO with and without a 7-mm resection. The vertical deviation degree in primary position and the eyeball motility were recorded and evaluated. Results The vertical deviation degree in primary position were 0△-10△ (3.5 △± 2.7△) after 3 months operation in the standard group,while 0△-12△ (3.3△±3.6△) in the resection group. There were no significant differences between two groups (P＞ 0.05). In the standard group, 2 cases revealed +2 inferior oblique muscle overaction (IOOA), 7 cases revealed +1 and 21 cases revealed 0 after 3 months operation. In the resection group, 1 case revealed +2 IOOA, 4 cases revealed +1 and 24 cases revealed 0 after 3 months operation. There were no significant differences between two groups(P＞ 0.05 ). The presence or absence of IOOA did not influence the result of ATIO for either group. Conclusions ATIO is an effective treatment for DVD and can be used to treat DVD in patients without IOOA. A 7-mm resection with the standard ATIO has no advantage to improve the surgery outcome.

Secondary Superior Oblique Overaction after Inferior Oblique Muscle Myectomy in a Patient Misdiagnosed with Inferior Oblique Muscle Overaction

PURPOSE: To report a case of superior oblique muscle tenotomy in a patient with suspected bilateral inferior oblique muscle overaction. The patient showed secondary superior oblique muscle overaction and inferior oblique muscle underaction after inferior oblique muscle myectomy. CASE SUMMARY: The patient showed V-pattern exotropia with suspected bilateral inferior oblique muscle overaction. After bilateral lateral rectus muscle recession with bilateral inferior oblique muscle myectomy, the patient showed secondary esotropia and inferior oblique underaction. After the surgery, progressive secondary superior oblique muscle overaction continued and finally, a superior oblique muscle tenotomy was performed. After the superior oblique muscle tenotomy, the superior oblique muscle overaction was corrected but the inferior oblique muscle underaction continued. CONCLUSIONS: After an inferior oblique muscle myectomy, secondary superior oblique muscle overaction can develop. Thus, caution should be taken in diagnosing inferior oblique muscle overaction in patients who show minimally inferior oblique muscle overaction as well as the surgical methods chosen.

A Case of Congenital Absence of the Superior Oblique Muscle Treated With Anterior and Nasal Transposition of the Inferior Oblique Muscle

PURPOSE: To report a patient with absence of the superior oblique (SO) muscle of the left eye, who showed improvement after anterior and nasal transposition of the inferior oblique muscle for left hyperdeviation and right head tilt. CASE SUMMARY: A two-year-old boy presented with hypertropia of the left eye and right head tilt. Alternate prism-cover test in the primary position demonstrated 18 prism diopters (PD) of left hypertropia, which increased to 35 PD in the left head tilt position. A version test demonstrated overaction of the left inferior oblique muscle and underaction of the left superior oblique muscle. As an orbit CT scan showed absence of the SO muscle, the patient was diagnosed with congenital absence of SO and left anterior and nasal transposition of the inferior oblique muscle was performed. Three weeks after surgery, the patient presented with orthotropia at distant and near. The version test revealed normal oblique muscles. There was no vertical deviation shown on the Bielschowsky head tilt test. The abnormal head posturing was no longer observed. CONCLUSIONS: The authorsreport a patient manifesting abnormal head posture and hypertropia, diagnosed with absence of SO muscle, which was successfully corrected using anterior and nasal transposition of the inferior oblique muscle.

An Anatomic Study of the Infraorbital Fat Compartments in Adult Cadavers

PURPOSE: This study investigated the anatomy of infraorbital fat and the relationship between surrounding structures and infraorbital fat. METHODS: Forty-one orbits from adult Korean cadavers were dissected. Among them 20 orbits were male and 21 orbits were female. The cadavers were perfused and embalmed in formalin solution. The skin and orbicularis oculi muscle were dissected to expose the arrangement and compartments of infraorbital fat. A punctal probe was used to find a deeper fat compartment lying under the another compartment. The width of each compartment and the distances from the inferior orbital rim and from the lower lid margin to the topmost point of each compartment were measured using a digital caliper. The distance from the top of the medial compartment and lower lid margin to the first appearance of the inferior oblique muscle, located between the medial and the central fat compartments, were measured, respectively. RESULTS: The width of the medial compartment was 11.49+/-2.54 mm, the central compartment was 21.78+/-5.69 mm, and the lateral compartment was 17.94+/-4.99 mm. The distance from the inferior orbital rim to the medial compartment was 8.13+/-2.72 mm, to the central compartment was 9.91+/-3.44 mm, to the lateral compartment was 9.58+/-3.76 mm. The distance from the lower lid margin to the medial compartment was 5.55+/-1.22 mm, to the central compartment was 7.09+/-3.22 mm, and to the lateral compartment was 5.41+/-3.07 mm. The distance from the inferior oblique muscle to the medial compartment was 9.09+/-2.63 mm, and to the lower lid margin was 13.60+/-2.27 mm. CONCLUSIONS: Our study evaluates the normal anatomy of the infraorbital fat compartments in Korean patients and suggests a useful index for lower blepharoplasty and lower orbital surgery.

The Effect of Inferior Oblique Muscle Surgery in Congenital Superior Oblique Palsy

PURPOSE: To compare the postoperative results of inferior oblique muscle operation in congenital superior oblique palsy (CSOP) according to the preoperative vertical deviation. METHODS: This study reviewed medical records of 26 patients who were diagnosed as CSOP with the largest vertical deviation at adducted position and incomitant vertical strabismus from May 2003 to April 2004 at hospital. The patients were divided into two groups, the group 1 (18 patients) shows less than 20 prism diopter (PD) vertical deviation at the primary position, the group 2 (10 patients) shows no less than 20 PD vertical deviation at the primary position preoperatively. We performed operation of the inferior oblique muscle (IOM) for both group. We evaluated the surgical effect at the primary position and both lateral gaze after 3 months. and performed reoperation as needed. RESULTS: Mean correction amount of vertical deviation at primary position of two groups were 11.6+/-2.7 PD in the group 1 and 7.4+/-3.5 PD in the group 2. Postoperative vertical deviation was decreased compared to preoperative value and it was statistically significant. But there were statistically significant differences in the corrected amount after inferior oblique muscle operation between two groups at all gazes. Surgical result of group 1 was successful (100%), but in group 2, all failed (100%) and needed reoperation. CONCLUSIONS: This study showed that corrected amount with IOM operation was smaller in CSOP with no less than 20 PD vertical deviation at primary position and incomitant vertical strabismus. It may be taken into consideration when operation for rectus and oblique musle were performed simultaneously in CSOP.

Characteristics and Outcome in Horizontal Strabismus Combined with Unilateral Superior Oblique Palsy

PURPOSE: To review the clinical characteristics and treatment outcomes in horizontal strabismus combined with unilateral superior oblique palsy (SOP). METHODS: A retrospective review of medical records was conducted in 21 patients with unilateral SOP treated between January 2001 and December 2005. Patients had more than 6 months of follow-up at the Department of Ophthalmology, Wonju College of Medicine. RESULTS: Among 21 patients (11 male, 10 female) with unilateral SOP, 57.1% of patients had horizontal strabismus. The mean vertical deviation was 12.56+/-3.81 (8~24) PD. All patients with horizontal strabismus had exotropia and the mean deviation was 10.57+/-4.58 (6~20) PD. A standard 10mm inferior oblique (IO) recession was performed uniformly at the paretic eye in all patients. In 7 of the patients (58.3%, exotropia greater than or equal to 10PD), horizontal rectus muscle recession was performed simultaneously. In these 7 cases, vertical and horizontal deviation less than or equal to 4PD was achieved (one patient with 10PD remaining hypertropia excluded). In 5 cases with exodeviation less than 10PD, isolated IO recession without horizontal rectus recession on the ipsilateral side achieved orthophoria in the primary position. In 9 cases of isolated SOP, all patients showed orthophoria in the primary position. CONCLUSIONS: This study demonstrates horizontal strabismus is combined with unilateral SOP in a high percentage of patients. Additionally, in all cases, all the incidents of horizontal deviation was involved exotropia. A standard 10 mm recession of the IO in combination with horizontal rectus recession is an effective surgical technique. It has an especially high success rate in patients with unilateral SOP (< or =14PD vertical deviation) with exodeviation greater than 10PD. In patients with exodeviation less than 10PD, an isolated IO recession is sufficiently effective.

Antielevation Syndrome after Unilateral Anteriorization of the Inferior Oblique Muscle

PURPOSE: To report antielevation syndrome with restriction of elevation on abduction in the operated eye and overaction (OA) of the inferior oblique muscle (IO) of the contralateral eye after unilateral IO anteriorization (AT). METHODS: Medical records were reviewed retrospectively in 8 of 24 patients who underwent unilateral IOAT. Four patients were referred from other hospitals after the same surgery. RESULTS: Four patients had infantile esotropes. The rest showed accommodative esotropia, superior oblique palsy, exotropia, and consecutive exotropia. The mean amount of hyperdeviation was 16.3 PD (10~30). The mean restriction of elevation on abduction in the operated eye was -1.6 (-1~-4) and IOOA of the contralateral eye was +2.7 (+2~+3). IOAT of nonoperated eyes in 4 patients, IO weakening procedure of anteriorized eyes in 2 patients, and IO myectomy on an eye with IOAT in 1 patient were performed. Ocular motility was improved after surgery in all patients. CONCLUSIONS: Unilateral IOAT may result in antielevation syndrome. Therefore bilateral IOAT is recommended to balance antielevation in both eyes. A meticulous caution is needed when performing unilateral IOAT.

The Effect of Graded Recession and Anteriorization on Unilateral Superior Oblique Palsy

PURPOSE: We wanted to examine the effect of graded recession and anteriorization of the inferior oblique muscle on patients suffering from unilateral superior oblique palsy. METHODS: Inferior oblique muscle graded recession and anteriorization were performed on twenty-two patients (22 eyes) with unilateral superior oblique palsy. The recession and anteriorization were matched to the degree of inferior oblique overaction and hypertropia. The inferior oblique muscle was attached 4 mm posterior to the temporal border of the inferior rectus muscle in six eyes, 3 mm posterior in five eyes, 2 mm posterior in five eyes, 1 mm posterior in five eyes, and parallel to the temporal border in one eye. RESULTS: The average angle of vertical deviation prior to surgery was 11.3+/-3.9 prism diopters (PD). The total average correction in the angle of vertical deviation after surgery was 10.8+/-3.8 PD. In the parallel group, the average reduction was 14 PD. After surgery, normal inferior oblique muscle action was seen in eighteen of twenty-two eyes (81.8%). CONCLUSIONS: Graded recession and anteriorization of the inferior oblique muscle is thought to be an effective surgical method to treat unilateral superior oblique palsy of less than 15 PD.

The Effect of Inferior Oblique Weakening Procedures on the Correction of Ocular Torsion

PURPOSE: To examine changes in ocular torsion after the weakening procedure for the inferior oblique muscle in patients with overaction of inferior oblique muscle (IOOA). METHODS: Twenty-eight eyes that had undergone the graded IO anteriorization combined with recession were evaluated. Twelve eyes from 11 patients had IOOA due to superior oblique muscle palsy (SOP) and 16 eyes from 9 patients had primary IOOA. Fundus photograph was taken to examine changes in torsional deviation before and after surgery. RESULTS: The average torsional deviation decreased from +17.5 +/- 7.3 degrees before surgery to +6.4 +/- 5.8 degrees after surgery, with the amount of correction being 11.1 degrees. It was corrected by 12.6, from +19.1 +/- 7.7 degrees to +6.5 +/- 4.8 degrees, in patients with SOP, and by 10 degrees, from +16.3 +/- 6.9 degrees to +6.3 +/- 6.6 degrees, in patients with IOOA (p<0.05). CONCLUSIONS: About 11o excyclotorsional correction was observed in patients with IOOA after IO anteriorization combined with recession.