Parks 3-step test

Background: The Parks 3-step test is an important test in the diagnosis of a single cyclovertical muscle palsy. Purpose: This video is presented to provide a simplified and easy understanding of the Parks 3-step test for post-graduate residents. Synopsis: The video contains a description of the steps to perform a 3-step test, the results of the test in a case of superior oblique palsy, the conditions that mimic a positive 3-step test, and how to identify these mimicking conditions. Highlights: This is a simple demonstration of a classic clinical diagnostic procedure.

The Clinical Course of Superior Oblique Tuck Surgery in Patients with Unilateral Superior Oblique Palsy

PURPOSE: To evaluate the effects of surgery depending on the follow-up duration after superior oblique tuck was performed as the first surgery in unilateral superior oblique palsy patients. METHODS: Sixteen patients who were followed-up for a minimum of 3 months were retrospectively evaluated. The vertical deviation, abnormal head posture, superior oblique underaction, and inferior oblique overaction were evaluated before and at 3, 6, and 12 months after the surgery and at the last follow-up. The angle between the center of the optic disc and fovea (disc-fovea angle) was measured using fundus photography to investigate changes in ocular torsion. RESULTS: The mean follow-up period was 24.9 ± 21.9 months and the mean tuck was 11.4 ± 4.0 mm. Vertical deviation <7 prism diopters in the primary position was observed in 53.9% of patients at 3 months postoperatively, 50.0% at 6 months, 83.3% at 12 months, and 62.5% at the last follow-up (p = 0.55). Head posture was improved in 66.7% of patients at 3 months, 71.4% at 6 months, 50% at 12 months, and 80% at the last follow-up after surgery (p = 0.73). Ocular torsion was decreased in 37.5% of patients at 3 months postoperatively, 66.7% at 6 months, 75% at 12 months, and 80.0% at the last follow-up (p = 0.11). Superior oblique underaction was improved in 100%, 77.8%, 60%, and 75% of the patients and inferior oblique overaction was improved in 100%, 88.9%, 85.7%, and 81.3% of the patients at postoperative month 3, 6, and 12, and at the last follow-up, respectively. CONCLUSIONS: Superior oblique tuck resulted in the maintenance of an improved condition of patients at 3, 6, and 12 months postoperatively, and there was no significant difference in motor measurements between the follow-up periods.

Horizontal Effects of 10-mm Inferior Oblique Recession versus 14-mm Inferior Oblique Recession

PURPOSE: The aim of this study was to investigate the quantitative effect of inferior oblique (IO) 10- and 14-mm recession on postoperative horizontal deviation. METHODS: Patients (22 men and 18 women) who underwent IO recession were divided into two groups for comparison studies: group 1 (10-mm IO recession, 15 patients) and group 2 (14-mm IO recession, 25 patients). Preoperative and postoperative horizontal deviations were measured, and the resulting horizontal deviations from the 10- and 14-mm IO recession surgeries were compared. The effects of superior oblique underaction, IO overaction, and combined exodeviation on postoperative horizontal deviation were analyzed. RESULTS: Although group 1 did not show a significant horizontal deviation change after surgery (1.9 ± 4.5 prism diopters [PD], p = 0.452), group 2 had a meaningful horizontal change after 14-mm recession (2.2 ± 3.8 PD, p = 0.022). Both groups showed a significant esodrift in horizontal deviation (group 1, p = 0.017; group 2, p = 0.030) in patients with exodeviation over 8 PD. The mean change in horizontal deviation was 6.0 ± 5.4 PD for group 1 and 9.0 ± 5.0 PD for group 2. Although the amount of superior oblique underaction did not affect the extent of change in horizontal deviation, patients with severe IO overaction showed a significant change in horizontal deviation after 14-mm IO recession. CONCLUSIONS: Fourteen-millimeter IO recession could make a statistically significant change in horizontal deviation after surgery. In addition, esodrift should be considered after IO recession in patients with a preoperative exodeviation greater than 8 PD or severe IO overaction.

Surgical Management of Superior Oblique Muscle Palsy in Hypertropia 16 Prism Diopters or More

PURPOSE: Isolated inferior oblique weakening procedure is an effective treatment for patients with superior oblique muscle palsy who had up to 15 prism diopters (PD) of vertical deviation in the primary position, but 2-muscle surgery is needed for patients with larger deviations. Herein, we report the surgical results of simultaneous 2-extraocular muscle surgery for large primary position hypertropia 16 PD or more caused by superior oblique palsy. METHODS: This study was a retrospective review of the records of patients who presented with central gaze hypertropia 16 PD or more and underwent simultaneous 2-extraocular muscle surgery between January 2003 and June 2014 in Severance Hospital. The patients were divided into 3 groups: 43 patients who underwent inferior oblique (IO) myectomy and contralateral inferior rectus (IR) recession (Group 1), 10 patients who underwent IO myectomy and superior rectus (SR) recession (Group 2), and 8 patients who underwent SR recession and contralateral IR recession (Group 3). Criteria for success included correction of head posture and a primary position alignment within 5 PD of vertical deviation. RESULTS: Mean preoperative alignment at primary gaze was 25.5 ± 7.1 PD (range, 16-60 PD) compared to the postoperative value of -1.3 ± 6.8 PD (range, -20~25 PD) (p < 0.001). Surgery was successful in 49 (80%) patients. Nine (15%) patients were overcorrected and the other 3 (5%) patients were undercorrected. Success rate was the highest in subjects who underwent IO myectomy and contralateral IR recession. Among the 24 patients who did not receive combined horizontal muscle surgery, horizontal deviations decreased from 10.4 ± 2.7 PD to 1.5 ± 5.5 PD (p < 0.001) CONCLUSIONS: Two-muscle surgery can be effective in patients with large hypertropia 16 PD or more. Additionally, horizontal deviations are more likely to be resolved with vertical muscle surgery alone. However, IO myectomy combined with ipsilateral SR recession can cause overcorrection postoperatively, so surgical dose should be reduced when performing weakening procedure of two elevators in one eye.

Effect of strabismus surgery on torticollis caused by congenital superior oblique palsy in young children.

Purpose: To evaluate the outcome of strabismus surgery for congenital superior oblique palsy (SOP) in relation to correction of head tilt and hypertropia. The cohort of patients mainly involved very young children. This is the first study to use a standardized instrument to objectively measure torticollis before and after surgery. Materials and Methods: A non‑comparative interventional case series of 13 cases of congenital superior oblique palsy with head tilt, who underwent simultaneous superior oblique tuck and inferior oblique recession between Jan 2000 and Dec 2008, were studied. Results: The mean duration of SOP until surgery was 36.8 months. Of the 12 unilateral cases, 8 were right‑sided. Mean follow‑up period was 17 months (range 7‑36). The outcome was determined at the last follow‑up. Mean pre‑and post‑operative hypertropia (p.d.) in forced primary position was 19 ± 7 and 2 ± 6, respectively (P < 0.0001). The head tilt reduced from mean of 17 ± 9 to 2 ± 2 degrees (P < 0.0001). Success, defined as hypertropia <5 PD and head tilt less than 5 degrees, was achieved in 69% (9/13. C.I. 42‑88%) and 85% (11/13. C.I. 56‑96%), respectively. The success rate for achieving both criteria was 61.5% (C.I. 35‑88%). Five patients required additional surgery; usually a contralateral inferior rectus muscle recession, which was successful in all cases. One case developed asymptomatic Brown syndrome (7.69% ‑ C.I. 6.7‑22.2). Conclusions: Simultaneous superior oblique tuck and inferior oblique muscle recession can successfully treat selected cases of congenital superior oblique palsy. About one‑third required an additional procedure, which led to total normalization of the head position.

Correction of Hypertropia Coexisting with Intermittent Exotropia

PURPOSE: To investigate the clinical features associated with hypertropia and report the surgical outcomes of hypertropia coexisting with exotropia. METHODS: We reviewed the medical records of 148 patients with intermittent exotropia coexisting with hypertropia over 4 PD who received exotropia surgery. The cases accompanied by apparent paralytic strabismus such as superior oblique palsy were excluded. Patients were divided into group I(clinically diagnosed hypertropia) and group II (non-specific hypertropia) and the clinical features of coexisting hypertropia and surgical outcomes were analyzed. RESULTS: Among the 148 patients, group Iconsisted of 38 patients (26%) and group II of 110 patients (74%). The average amount of preoperative hypertropia angle in primary gaze was 9.58 +/- 3.89 PD and 6.62 +/- 2.69 PD in group I and II, respectively. Group I included 12 patients with dissociated vertical deviation (DVD), 10 patients with unilateral inferior oblique overaction, 13 patients with asymmetric bilateral inferior oblique overaction and 3 patients with superior oblique overaction. Group II included 19 patients with comitant hypertropia (17%), head tilt positive pattern (simulated superior oblique palsy) was found in 84 patients (76.3%) and variable incomitance was observed. In group I, 29 patients received simultaneous horizontal muscle with hypertropia surgery. Postoperative hypertropia angle in group I was 1.41 +/- 2.93 PD and 4 cases were considered surgical failure. In group II, hypertropia was resolved with horizontal muscle surgery only and the amount of postoperative hypertropia was 0.45 +/- 1.60 PD. CONCLUSIONS: In this study, vertical deviations in intermittent exotropia with concomitant hypertropia related to obvious oblique muscle dysfunction or DVD were corrected effectively by oblique or vertical rectus muscle surgery. Nonspecific hypertropia can be resolved after horizontal muscle surgery alone, however, for precise differential diagnosis, careful examination for variable clinical features is necessary before determining surgery.

Clinical Features and Natural Course of Superior Oblique Palsy

PURPOSE: To evaluate the natural course of superior oblique palsy (SOP) with objective criteria, and to show the contemporary etiology and recovery rates among several factors. The clinical features of SOP were compared to previous studies. METHODS: A retrospective chart review of 80 patients diagnosed with SOP between January 1, 2006 and December 31, 2011 was performed. RESULTS: Clinical SOP features showed variation when compared to previous studies. Out of 80 patients, 71 were identified with unilateral isolated and 9 bilateral cases of SOP. Twenty cases were congenital and 60 cases were acquired SOPs. Acquired SOPs were affected most commonly by trauma (31%) and vascular disease (30%). Twenty-four out of 49 patients, who were followed up over 2 months after the first visit recovered, especially vascular origin cases, which was statistically significant (75%, p = 0.000). Patients with initial vertical deviation smaller than 5 Prism diopters (PD) experienced a more successful recovery than patients with an initial deviation larger than 5 PD. CONCLUSIONS: SOP has different recovery rates depending on the etiology. Accurate ocular examination and understanding of SOP etiology are necessary for successful treatment.

The Outcome of Graded Inferior Oblique Recession in the Congenital Unilateral Superior Oblique Palsy

PURPOSE: To examine changes in vertical deviation and improvement in head tilt after graded inferior oblique (IO) recession surgery in patients with congenital unilateral superior oblique palsy (SOP). Frequency of inferior oblique overaction (IOOA) or bilateral SOP in the contralateral eye after surgery was also investigated. METHODS: We retrospectively reviewed medical records of 65 patients who had undergone graded IO recession surgery in unilateral congenital SOP with at least 1 year of postoperative follow-up. Postoperative vertical deviation was classified as excellent (under 3 prism diopters, PD), good (4-7 PD) or poor (over 8 PD). The occurrence of IOOA was considered if more than 2 IOOAs were observed in the contralateral eye after surgery. RESULTS: Forty-five of the 65 patients (69%) obtained excellent results and 67.3% had improvement in head tilt after surgery. IOOA in the contralateral eye was not observed in any patients before surgery. Postoperative IOOA in the contralateral eye occurred in 9 patients (13.8%) and a diagnosis of masked bilateral SOP was made in 1 patient (1.5%). CONCLUSIONS: The graded IO recession procedures are considered to be an effective surgical method for the treatment of unilateral congenital SOP. However, IOOA or masked bilateral SOP occurring in the contralateral eye was observed in 15.3% of the patients undergoing surgery.

Contemplation of the Surgical Normogram of Lateral Rectus Recession for Exotropia Associated with Superior Oblique Palsy

PURPOSE: To suggest a surgical normogram for lateral rectus recession in exotropia associated with unilateral or bilateral superior oblique muscle palsy (SOP). METHODS: We retrospectively reviewed the charts of 71 patients with exotropia who were successfully corrected over one year. Each patient had undergone unilateral or bilateral rectus recession associated with uni- or bilateral inferior oblique (IO) 14 mm recession, using a modified surgical normogram for lateral rectus (LR) recession, which resulted in 1 to 2 mm of reduction of LR recession. We divided all patients into 2 groups, the 34 patients who had undergone LR recession with unilateral IO (UIO) recession group and the remaining 37 patients who had undergone LR recession with bilateral IO (BIO) recession group. Lateral incomitancy was defined when the exoangle was reduced by more than 20% compared to the primary gaze angle. The surgical effects (prism diopters [PD]/mm) of LR recession were compared between the two groups using the previous surgical normogram as a reference (Parks' normogram). RESULTS: The mean preoperative exodeviation was 20.4 PD in the UIO group and 26.4 PD in the BIO group. The recession amount of the lateral rectus muscle ranged from 4 to 8.5 mm in the UIO group and 5 to 9 mm in the BIO group. Lateral incomitancy was noted as 36.4% and 70.3% in both groups, respectively (p = 0.02). The effect of LR recession was 3.23 +/- 0.84 PD/mm in the UIO group and 2.98 +/- 0.62 PD/mm in the BIO group and there was no statistically significant difference between two the groups (p = 0.15). CONCLUSIONS: Reduction of the LR recession by about 1 to 2 mm was successful and safe to prevent overcorrection when using on IO weakening procedure, irrespective of the laterality of SOP.

Surgical Results of Modified Harada-Ito Operation for Excyclotorsion

PURPOSE: We evaluated the efficacy of the modified Harada-Ito operation for excyclotorsion in acquired superior oblique palsy patients after trauma. METHODS: This study represents a retrospective review of 10 eyes in 9 patients who were surgically treated for excyclotorsion. Cyclotorsion was measured with the double maddox-rod test and fundus photographies preoperatively and postoperatively. RESULTS: The median measured change in excyclotorsion before and after the surgery in the primary gaze was reduced from 15.67 +/- 6.00 to 4.78 +/- 3.42 according to fundus photographies and from 12.30 +/- 6.27 to 2.45 +/- 3.73 according to the double maddox-rod test. Subjective and objective changes in excyclotorsion werer not significantly different. CONCLUSIONS: The Modified Harada-Ito operation is an effective treatment for correcting excyclotorsion. Although not statistically significant, the amount of excyclotorsion on fundus photography is exaggerated. This point should be considered to achieve effective surgery.

Superior Rectus Muscle Recession for Residual Head Tilt after Inferior Oblique Muscle Weakening in Superior Oblique Palsy

PURPOSE: Residual head tilt has been reported in patients with superior oblique muscle palsy (SOP) after surgery to weaken the inferior oblique (IO) muscle. The treatments for these patients have not received appropriate attention. In this study, we evaluated the superior rectus (SR) muscle recession as a surgical treatment. METHODS: The medical records of 12 patients with SOP were retrospectively reviewed. Each of these patients had unilateral SR muscle recession for residual head tilt after IO muscle weakening due to SOP. The residual torticollis was classified into three groups on the basis of severity: mild, moderate, or severe. Both IO muscle overaction and vertical deviation, features of SOP, were evaluated in all patients. The severity of the preoperative and postoperative torticollis and vertical deviation were compared using a paired t-test and Fisher's exact test. RESULTS: The torticollis improved in nine of 12 (75%) patients after SR muscle recession. The difference between the preoperative and postoperative severity of torticollis was statistically significant (p = 0.0008). After surgery, the mean vertical deviation was significantly reduced from 12.4 prism diopters to 1.3 prism diopters (p = 0.0003). CONCLUSIONS: Unilateral SR muscle recession is an effective method to correct residual head tilt after IO muscle weakening in patients with SOP. This surgical procedure is believed to decrease head tilt by reducing the vertical deviation and thereby the compensatory head tilt.

Clinical Characteristics of Abnormal Postures of the Head and Neck Caused by Unilateral Superior Oblique Palsy

OBJECTIVE: To present the clinical characteristics of abnormal posture of the head and neck (APHN) caused by unilateral superior oblique palsy (USOP) for differential diagnosis of childhood APHN. METHOD: The medical charts of children who came to Department of Physical Medicine and Rehabilitation, Ajou University Medical Center from 2003 to 2008 for APHN were reviewed with special reference to ocular causes of APHN. Children who showed a positive Bielschowsky's head tilt test were strongly suspected to have USOP. In-depth ophthalmic evaluations were done after 6 months of age to identify USOP for those children. The clinical characteristics of children with USOP were compared with those of children with congenital muscular torticollis. RESULTS: Sixteen children were diagnosed with APHN related to ocular causes. Seven children out of 16 (43.8%) had APHN secondary to USOP, which was the most common ocular cause of APHN. The initial clinical presentation of 7 children with USOP was contralateral laterocollis toward the shoulder on the non-USOP side at a mean age of 15.57+/-12.55 months; USOP was diagnosed at a mean age of 19.07+/-11.29 months. APHN was aggravated by staring at objects, and craniofacial asymmetry was not evident at this age compared to children with congenital muscular torticollis. CONCLUSION: The clinical characteristics of USOP were presented, which showed laterocollis toward the shoulder of non-USOP. Differential diagnosis of APHN is critical for proper management for APHN and high index of suspicion for USOP by non-ophthalmologic physicians could make earlier diagnosis of USOP possible.

Postoperative binocular visual function in 28 patients with congenital superior oblique palsy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the postoperative changes of binocular visual function in patients with congenital superior oblique palsy.METHODS: Eye position and binocular visual function were examined in 28 patients with congenital superior oblique palsy pre- and post-operatively. The results were statistically analyzed.RESULTS: The normal eye position rate after operation was 89.3%. There were 9 patients who gained simultaneous perception after operation, while 13 patients gained fusion as many as that gained stereoacuity. There was statistically significant difference between postoperative and preoperative eyes (P<0.05). Near stereoacuity was improved after operation. Patients who had better visual acuity and low strabismus degrees as well as fusion had a better recovery.CONCLUSION: The operation could improve the eye position and rebuild the binocular visual function of the congenital superior oblique palsy. The recovery of binocular visual function was related to visual acuity and strabismus degrees of the patients and whether they had fusion function.

Comparison of Inferior Oblique Myectomy, Recession, and Anterior Transposition in Unilateral Congenital Superior Oblique Palsy

PURPOSE: To compare the clinical outcomes of myectomy, recession, and anterior transposition (AT) of the inferior oblique muscle in congenital unilateral superior oblique palsy. METHODS: A total of 40 patients who were followed for longer than three months postoperatively and, who underwent inferior oblique myectomy, recession, or AT were evaluated retrospectively. RESULTS: We compared the result of inferior oblique myectomy, recession, and AT in congenital unilateral superior oblique palsy. The decreased amounts of inferior oblique overaction (IOOA) were 2.24+/-0.67, 2.00+/-0.76, 3.00+/-1.15 for myectomy, recession, and AT, respectively. Improvement of superior oblique underaction was 0.80+/-0.66, 0.86+/-0.83, 1.00+/-0.58, and the changes in hyperdeviation were 10.96PD, 8.25PD, 14.86PD for myectomy, recession, and AT, respectively. There were no significant differences among the surgical methods. The proportion of patients who showed IOOA in the contralateral eye after operation were 20.0% in myectomy, 25.0% in recession, and 57.1% in AT. CONCLUSIONS: The efficacies of myectomy, recession, and AT of inferior oblique muscle in the congenital unilateral superior oblique palsies showed no significant differences among methods. The AT group tended to show a larger effect than did the other methods, along with a high development percentage of contralateral eye IOOA. Based on these results, AT of the IO shoud be selectively chosen in more severe cases.

Differential Diagnosis and Management of Abnormal Posture of the Head and Neck

Abnormal posture of the head and neck can happen to anybody from neonates to adults, which requires appropriate interventions according to etiologies. Congenital muscular torticollis is the most common cause of abnormal posture of the head and neck in infancy, where early intervention as soon as possible is critical for better therapeutic outcome. Childhood laterocollis is heterogeneous condition, which needs etiological diagnosis for the proper management. Cervical dystonia is the most common form of focal dystonia and an overview on clinical presentations and therapeutic options including chemodenervation with botulinum toxin injection was provided. Abnormal posture of the head and neck of acute onset could be a sign of serious conditions and needs differential diagnosis.

The Clinical Characteristics of Superior Oblique Palsy Associated With Intermittent Exotropia

PURPOSE: The goal of this study was to determine the clinical characteristics of patients with intermittent exotropia (IXT) associated with hypertropia. METHODS: This study recruited 268 hospital patients with IXT associated with hypertropia. After taking history, measuring the angle of deviation, conducting an ocular motor examination, performing a Bielschowsky head tilt test and taking a fundus photograph, the clinical characteristics of 23 patients diagnosed with superior oblique palsy (SOP) were investigated. RESULTS: Twenty-three patients (8.6%) of the 268 subjects with IXT associated with hypertropia were diagnosed with SOP. The average angle of exodeviation was 17.1+/-3.8PD and the angle of hypertropia at primary position was 12.9+/-5.9PD. Excyclotorsion of an eyeball was observed in 19 patients (82.6%), the Bielschowsky head tilt test was positive in all patients, and head tilt or face turn was found in 12 (52.2%) patients. All subjects had inferior oblique overaction, and 20 (86.9%) had superior oblique underaction. Operations to weaken the inferior oblique muscle of the paralytic eye and for horizontal muscles were conducted at the same time. The angle of exodeviation and the angle of hypertropia were, on average, 1.8+/-3.6PD and 2.4+/-2.2PD, respectively, 6 months after the operation. CONCLUSIONS: When patients with intermittent exotropia have hypertropia, the possibility of SOP should be considered. SOP can be detected by determining a history of head tilt and conducting a Bielschowsky head tilt test. Surgical treatment for SOP is advised.

The Effect of Minimal Amount Inferior Oblique Recession in Superior Oblique Palsy

PURPOSE: To investigate the effect of vertical deviation change, head tilt and diplopia relief, we performed a minimal amount of inferior oblique recession regardless of the vertical deviation angle and the degree of inferior oblique overaction (IOOA) in superior oblique palsy patients. METHODS: We retrospectively analyzed 20 cases of unilateral congenital or acquired superior oblique palsy, which were treated with inferior oblique muscle recession from May 2005, to August 2007. We compared vertical deviation change, head tilt and diplopia relief following surgery. Improvement of head tilt was determined by patient satisfaction measurements. The inferior oblique muscle was attached 4 mm posterior and 2 mm temporal to the lateral border of the inferior rectus muscle insertion in all patients. RESULTS: The average angle of vertical deviation prior to surgery was 12.4 prism diopters (PD), and the total average correction in the angle of vertical deviation after surgery was 9.6PD. After surgery, head tilt improved in 13 of 16 eyes(81%), and of the four remaining eyes, vertical diplopia was absent. CONCLUSIONS: Although vertical deviation remained after surgery, if patients have enough vertical fusional amplitude, they should be able to overcome the diplopia and the head tilt. Judging from the indication of inferior oblique recession in diplopia and cosmetic problem in superior oblique palsy, a minimal amount of inferior oblique recession is thought to be an effective treatment of unilateral superioroblique palsy with no significant IOOA.

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.

Ocular Torsion in Unilateral Superior Oblique Palsy

PURPOSE: We evaluated the concordance of laterality of the paretic eye and the torsional eye in unilateral superior oblique palsy showing an inferior oblique overaction. METHODS: Thirty-nine patients diagnosed as having a unilateral superior oblique palsy were evaluated for visual acuity, refractive manifestation, ocular movement, prism cover test, and fundus photograph. Of these patients, 32 derived from congenital causes and 7 acquired the condition from trauma. An ocular movement exam was performed to check an inferior oblique overaction, and a fundus photograph was used to measure the ocular torsional amount. Inferior oblique myectomy or recession was performed along with horizontal strabismus surgery. RESULTS: Objective extorsion was presented in paretic eyes of 29 patients (74.4%) and nonparetic eyes of 10 patients (25.6%). The congenital superior oblique palsy patients were divided into two groups by the concordance of laterality of paretic eyes and torsional eyes. In the concordance group of 22 patients, the torsional amount was decreased from +17.69 degrees to +7.98 degrees and inferior oblique overaction from +2.27 degrees to +0.25 degrees after an inferior oblique muscle weakening procedure. In the discordance group of 10 patients, torsional amount was decreased from +16.97 degrees to +8.73 degrees and inferior oblique overaction from +2.50 degrees to +0.21 degrees postoperatively. In acquired oblique palsy patients, all patients showed the concordance of laterality, and the torsional amount was decreased from +16.76 degrees to +8.80 degrees and inferior oblique overaction from +2.5 degrees to +0.21 degrees after inferior oblique weakening procedure. CONCLUSIONS: We found that the paretic eye and the torsional eye may not coincide in congenital superior oblique palsy but always coincide in acquired oblique palsy after trauma. After an inferior oblique muscle weakening procedure, ocular torsional amount of paretic or sound eye is decreased in every case.

The Relationship of Hypertropia, Inferior Oblique Overaction and Extorsion in Congenital Superior Oblique Palsy

PURPOSE: To evaluate the correlation among hypertropia, inferior oblique overaction (IOOA), and extorsion. METHODS: Thirty-one patients with congenital unilateral superior oblique palsy were evaluated. Visual acuity tests, refraction tests, ocular movement tests, prism cover tests, and fundus photography were performed. The correlations of vertical deviation, IOOA, and extorsion were analyzed. The operation method involved weakening the inferior oblique muscle, and then a comparison was made between measurements 1 month preoperative and 1 month postoperative for vertical deviation, inferior oblique overaction, and extorsion. RESULTS: On average, preoperative hypertropia was 8.84+/-6.88 prism diopters (PD), IOOA was 2.20+/-0.69, and extorsion was 18.06+/-5.83 degrees. The Pearson's correlation of IOOA and extorsion, hypertropia and IOOA, and extorsion and hypertropia were r=0.620, r=0.327, and r=0.126, respectively. Postoperative hypertropia, IOOA, and extorsion were reduced to 1.42+/-3.11PD, 0.42+/-1.11, and 8.63+/-5.09, respectively. CONCLUSIONS: Both extorsion and hypertropia showed significant positive correlations with IOOA, whereas hypertropia and extorsion revealed somewhat weaker positive correlations in congenital monocular superior oblique palsy. In addition, the amount of hypertropia was reduced, and extorsion and IOOA improved after recession of the inferior oblique muscle.