Secondary Inferior Oblique Overaction Research Articles

Evaluation of change in objective cyclotorsion after various inferior oblique–weakening procedures

PurposeTo study the effect of four types of inferior oblique–weakening procedures on ocular torsion: inferior oblique recession (IOR), recession and antero-positioning (RAP), anterior transposition as practiced by Elliot and Nankin (EN), and anterior and nasal transposition (ANT). MethodsThe medical records of 72 consecutive patients >10 years of age undergoing inferior oblique weakening for primary or secondary inferior oblique overaction (IOOA) with or without horizontal rectus surgery were reviewed retrospectively. The 106 included eyes were assigned to one of the four groups according to the type of inferior oblique–weakening procedure. The severity of IOOA and the amount of V pattern guided the choice of procedure. IOOA, disk-fovea angle (DFA), and the amount of V pattern were recorded preoperatively. Measurements were repeated postoperatively at 1 week, 4 weeks, and 3 months. Change in the DFA was used to study the change in objective cyclotorsion in all four groups. ResultsA significant incyclotorsional shift was seen in all four groups at postoperative 3 months. The mean reduction in excyclotorsion 3 months postoperatively was 3.65° ± 4.84° for IOR, 5.31° ± 4.64° for RAP, 6.10° ± 3.89° for EN, and 16.62° ± 8.72° ANT; it was significantly higher in the ANT group compared with the other three groups. Reduction in DFA was also correlated with preoperative DFA overall, and for all procedures except IOR (P ≤ 0.005). ConclusionsAll four inferior oblique–weakening procedures reduced excyclotorsion; the largest reductions in our study were seen in cases treated using ANT of the inferior oblique.

Long-Term Efficacy of Inferior Oblique Myectomy Accompanied with Tenon’s Capsule Closure: Objective Analysis Using Nine-Gaze Photographs

Background: The aim is to evaluate the long-term efficacy of inferior oblique (IO) myectomy combined with Tenon's capsule closure to prevent muscle reattachment to the sclera. Methods: We retrospectively reviewed the medical records of 18 patients with primary and secondary IO overaction who underwent IO myectomy accompanied by Tenon's capsule closure. Patients were followed up for at least 1 year after the surgery. The main outcome measures included oblique muscle dysfunction, which was objectively graded through computerized analysis of nine-gaze photographs, and the amount of vertical deviation in the primary position using alternate prism cover testing. Results: After a mean follow up of 2.5 years, the grade of IO overaction decreased from +2.2 ± 1.0 to -0.8 ± 1.0 (p < 0.001). In patients with secondary IO overaction with superior oblique (SO) palsy, SO underaction improved from -2.2 ± 1.5 to -0.2 ± 1.8 (p = 0.006). Successful vertical deviation in the primary position of seven prism diopters or less was achieved in 83.3% of the patients. Underaction of the IO was observed in 11.1% of patients, whereas none of the patients showed antielevation syndrome. Conclusion: IO myectomy combined with Tenon's capsule closure might be safe and effective for the treatment of primary and secondary IO overaction in the long term.

Evaluation of the effect of unilateral and bilateral inferior oblique myectomy on fundus torsion in primary and secondary inferior oblique overaction.

This article evaluates the effects of unilateral and bilateral inferior oblique myectomy (IOM) on fundus torsion in primary and secondary inferior oblique overaction (IOOA). This study analyzed 230 OCT images of 53 eyes of 32 patients who had undergone IOM by a single surgeon in the last two years. The disc-foveal angle (DFA) was calculated by digitally measuring the angle between the horizontal line passing through the geometric center of the optic disc and the curved line connecting the fovea to the geometric center of the optic disc. DFA was classified into intorsion, normal torsion, and extortion. The DFA was measured from the OCT images before the operation in the first week, first month, third month, and sixth month. When all the patients in our study were evaluated together, IOM statistically reduced the mean DFA in the third month (p=0.00). The DFA was higher in the secondary IOOA group than in the primary IOOA group (p=0.24). Bilateral IOM statistically significantly reduced DFA in the third month (p=0.00) and decreased the DFA difference between the two eyes in the third month (p=0.583). Unilateral IOM increased the DFA, rather than decreasing it, in the first week in operated eyes (p=0594) and increased the DFA difference between the two eyes after surgery (p=0.477). When we evaluated the localization of the macula as an intorsion, normal intorsion, or extortion, the extortion decreased from 36 to nine in the third month after bilateral IOM, and intorsion was seen in only two. Unilateral surgery did not significantly change fundus torsion in primary IOOA, and it caused intorsion in 3 of 6 (50%) operated eyes in secondary IOOA. Although unilateral IOM provides a clinical improvement in secondary IOOA, it increases the difference in DFA between both eyes and causes intorsion in 50% of patients. Masked IOOA was detected in 3 of 11 (27.3%) patients who underwent unilateral IOM. When deciding on unilateral surgery, the possibility of increased DFA difference between both eyes, intorsion in the operated eye, and masked IOOA in the other eye should be considered.

Inferior Oblique Anterior Transposition versus Myectomy for Inferior Oblique Overaction: Systematic Review and Meta Analysis.

The objective of this study was to compare the outcomes of inferior oblique anterior transposition (IOAT) versus inferior oblique myectomy (IOM) in patients with primary inferior oblique overaction (IOOA) or secondary IOOA to superior nerve palsy. A systematic review and meta-analysis were performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Guidelines and an electronic search was conducted to identify studies comparing IOAT versus IOM for IOOA. Residual inferior oblique function, reduction in hypertropia and post-operative complications were identified as primary outcomes. Secondary outcomes included superior oblique function, head tilt improvement, effect on the contralateral eye, operation time and macular changes. The analysis was based on fixed or random-effects modelling. Eleven studies enrolling 729 patients were identified. Inferior oblique function was not significantly different between both interventions, namely the elimination of IOOA (Odds Ratio[OR] = 0.97, P = 0.97), reduction in IOOA (Mean Difference[MD] = -0.06, P = 0.68), post-operative inferior oblique under-action (OR = 1.06, P = 0.83) and residual overaction (OR = 0.71, P = 0.15). Similarly, no significant difference was noted between both groups in reducing hypertropia. Regarding post-operative complications, no significant difference was observed, including the incidence of anti-elevation syndrome (P = 0.10). No significant difference was noted regarding superior oblique function, improvement in head tilt, effect on the contralateral eye and macular changes, although surgical time was shorter in the IOM group. In conclusion, IOAT and IOM are both effective surgical procedures in the management of IOOA as they produced comparable outcomes in the improvement in hypertropia, post-operative inferior oblique function and incidence of complications.

Differences in gene expression between the primary and secondary inferior oblique overaction.

BackgroundThis study sought to define different adaptive changes in the molecular levels of the overacting inferior oblique muscle in primary and secondary inferior oblique overaction.MethodsThe inferior oblique muscles of patients with congenital superior oblique palsy (SOP) and those of patients with congenital esotropia were collected during surgery. RNA-seq technology was performed to detect the differentially expressed genes (DEGs) between the two groups. A comprehensive analysis of the gene expression profiles was then conducted, including the identification of DEGs, a Gene Ontology (GO) analysis, and a gene set enrichment analysis (GSEA). Finally, a protein-protein interaction (PPI) network was constructed with Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape software.ResultsWe identified 221 DEGs, of which 104 were significantly upregulated and 117 were downregulated in the SOP group. Additionally, several isoforms of the myosin heavy chain (MyHC) gene were found to be significantly and differentially expressed in the SOP group, including 3 upregulated fast-twitch MyHC isoforms (i.e., MYH1, MYH4, and MYH13) and 1 downregulated slow-twitch MyHC isoform (i.e., MYH3). The GO analysis indicated that the upregulated DEGs were mainly enriched in the muscle system process and muscle contraction. The GSEA analysis revealed that the upregulated pathways of ribosome, proteasome, oxidative phosphorylation, fatty acid metabolism, viral myocarditis, and cardiac muscle contraction were enriched.ConclusionsOur findings provide insights into the different molecular changes of inferior oblique muscle overaction secondary to SOP and suggest the potential pathological mechanisms of inferior oblique overaction (IOOA) in SOP. The results suggest that upregulated fast-twitch MyHC isoforms and downregulated slow-twitch MyHC isoform in SOP may contribute to the increased force of its inferior oblique muscle.

Inferior oblique anterior transposition according to a different grading scale for hyperdeviation with inferior oblique overaction

ObjectifDéfinir une échelle de classement de la transposition antérieure de l'oblique inférieur (IOAT, pour inferior oblique anterior transposition) chez des patients présentant une hyperdéviation et une hyperaction de l'oblique inférieur (IOOA, pour inferior oblique overaction), selon des données issues de notre étude rétrospective antérieure. NatureÉtude de cohorte prospective. ParticipantsTrente-huit patients qui ont fait l'objet d'un classement de l'IOAT. MéthodesLes patients ont été répartis en 5 groupes en fonction de l'importance de l'hyperdéviation en position primaire (PPHD, pour primary position hyperdeviation). L'oblique inférieur a été transposé soit à 2 mm postérieur, à 1 mm postérieur, en parallèle, à 1 mm antérieur ou à 2 mm antérieur à l'insertion du droit inférieur, respectivement. La réussite de l'intervention chirurgicale se définissait comme suit : réussite complète (PPHD ≤ 3 dioptries prismatiques [DP]), réussite partielle (PPHD > 3 et ≤ 6 DP) et échec (PPHD > 6 DP). RésultatsLa correction moyenne de l'hyperdéviation par groupe après l'IOAT se chiffrait à 9,50 ± 0,9 DP (fourchette : 8–10 DP), à 12,43 ± 1,5 DP (fourchette : 11–14 DP), à 16,67 ± 1,4 DP (fourchette : 15–18 DP), à 19,57 ± 1,7 DP (fourchette : 16–21 DP) et à 22,57 ± 5,8 DP (fourchette : 14–30 DP), respectivement. L'intervention a été une réussite chez 34 patients (89,5 %), une réussite partielle chez 3 patients (7,9 %) et un échec chez 1 patient (2,6 %). Tous les patients de notre étude présentaient une IOOA unilatérale avant l'intervention; une IOOA est apparue dans l’œil controlatéral de 9 patients (23,7 %) pendant le suivi postopératoire. Une limitation de –2 du regard vers le haut est apparue chez 4 patients (57,1 %) du groupe 5, sans qu'il soit besoin de recourir à la chirurgie. ConclusionsIl est possible d'obtenir un taux élevé de réussite grâce à notre échelle de classement de l'IOAT en présence d'IOOA primaire et secondaire s'accompagnant d'une hyperdéviation en position primaire.

Histopathological features and satellite cell population characteristics in human inferior oblique muscle biopsies: clinicopathological correlation

To investigate the correlation between clinical characteristics and histopathological and immunohistochemical features of inferior oblique muscles in patients with primary and secondary inferior oblique overaction. Inferior oblique muscle specimens of patients who underwent inferior oblique-weakening procedures for primary or secondary inferior oblique overaction were recruited. Subjects were mainly divided into two groups, each of which was further divided into two subgroups: group 1 included patients with primary inferior oblique overaction (subgroups, infantile esotropia vs acquired V-pattern esotropia), and group 2 included patients with secondary inferior oblique overaction (subgroups, congenital vs acquired trochlear nerve palsy). Inferior oblique overaction was graded between 0-4. Histopathologic changes, such as angular fibers, endo- and perimysial fibrosis, and vacuolization were categorized from mild to severe. Immunohistochemical markers Pax7, NCAM, and MyoD1 were used to detect satellite cells, a unique stem cell population in muscles presumably responsible from myofiber regeneration and maintenance, and their activity. Results were reported as stained cells per cross-section ratio. A total of 51 patients were included: 36 in group 1 and 15 in group 2. Satellite cell distribution and activity was significantly higher in group 1 (P<0.001). The angular fiber count and the degree of perimysial fibrosis was higher in the secondary group (P<0.001 and P=0.01, resp.). There was no correlation between clinical amount of inferior oblique muscle overaction and immunohistochemical markers. The differences in immunohistochemical parameters supported with histopathological changes between different strabismus etiologies imply that satellite cell population behavior varies among strabismus types.

Comparison of excyclotorsion following graded inferior oblique recession for primary versus secondary inferior oblique overaction.

To compare the changes in excyclotorsion after inferior oblique (IO) recession in patients with primary and secondary inferior oblique overaction (IOOA). We retrospectively analyzed the data obtained from patients with IOOA who underwent graded IO recession. The patients were followed up for at least 3mo after surgery. Fundus photographs were taken pre- and postoperatively, and the sum of the angles of torsion in both eyes was used to analyze changes in excyclotorsion. Patients were divided into two groups: those diagnosed with primary IOOA were enrolled in the 1'IOOA group, and those diagnosed with secondary IOOA caused by superior oblique palsy (SOP) were enrolled in the 2'IOOA group. Excyclotorsion before and after surgery were compared between the two groups. A total of 78 patients were enrolled in this study: 34 eyes in the 1'IOOA group and 44 eyes in the 2'IOOA group. In the 78 patients, torsional angle significantly decreased from 15.31°±7.40° to 12.11°±6.53° after IO recession (P<0.001). Mean preoperative torsional angle was larger in the 2'IOOA group than in the 1'IOOA group (P=0.03). In both groups, excyclotorsion significantly decreased after IO recession (P=0.001 and P<0.001, respectively); however, there was no significant difference in the amounts of changes in excyclotorsion between the two groups. Excyclotorsion is significantly larger in secondary IOOA than in primary IOOA, and a significant decrease in the torsional angle occurs after IO recession in both types of IOOA.

Inferior oblique retro-equatorial myopexy: An alternative weakening

Abstract Purpose To describe an alternative surgical approach to treat inferior oblique overaction, and report the first results of this technique. Materials and Methods A total of six consecutive eyes of six patients with primary or secondary inferior oblique overaction underwent inferior oblique retro-equatorial myopexy under general anaesthesia. The primary outcomes measured were the postoperative vertical deviation in the field of action of the inferior oblique muscle, and the intra- and postoperative surgical complications. Final results were evaluated at six-months after surgery Results The patient population consisted of three girls and three boys aged between three and seven years old. The mean preoperative inferior oblique overaction was 34° ± 4.6°, equivalent to 3+. Inferior oblique overaction was reduced in all patients with a mean reduction of 28° ± 1.98°, and the mean postoperative deviation was 6° ± 2.84°. Total success was achieved in four out of six eyes, and only one case remained under-corrected. No intra- or postoperative complications were reported. Conclusion Inferior oblique retro-equatorial myopexy is an alternative surgical approach for inferior oblique overaction. It is an efficient, safe, and reversible technique that could be used in cases of inferior oblique overaction between 2+ to 3+.

Miopexia retroecuatorial del músculo oblicuo inferior: un debilitamiento alternativo

PurposeTo describe an alternative surgical approach to treat inferior oblique overaction, and report the first results of this technique. Materials and methodsA total of 6 consecutive eyes of 6patients with primary or secondary inferior oblique overaction underwent inferior oblique retro-equatorial myopexy under general anaesthesia. The primary outcomes measured were the postoperative vertical deviation in the field of action of the inferior oblique muscle, and the intra- and postoperative surgical complications. Final results were evaluated at six-months after surgery. ResultsThe patient population consisted of 3girls and 3boys aged between 4 and 7years old. The mean preoperative inferior oblique overaction was 34°±4.6°, equivalent to 3+. Inferior oblique overaction was reduced in all patients with a mean reduction of 28°±1.98°, and the mean postoperative deviation was 6°±2.84°. Total success was achieved in four out of six eyes, and only one case remained under-corrected. No intra- or postoperative complications were reported. ConclusionInferior oblique retro-equatorial myopexy is an alternative surgical approach for inferior oblique overaction. It is an efficient, safe, and reversible technique that could be used in cases of inferior oblique overaction between 2+ to 3+.

Inferior Oblique Overaction: Anterior Transposition Versus Myectomy.

To compare the efficacy of inferior oblique myectomy and anterior transposition for correcting inferior oblique overaction (IOOA). This retrospective study was conducted on 56 patients with IOOA who had either myectomy or anterior transposition of the inferior oblique muscle from 2010 to 2015. The authors compared preoperative and postoperative inferior oblique muscle function grading (-4 to +4) as the main outcome measure and vertical and horizontal deviation, dissociated vertical deviation (DVD), and A- and V-pattern between the two surgical groups as secondary outcomes. A total of 99 eyes of 56 patients with a mean age of 5.9 ± 6.5 years were included (47 eyes in the myectomy group and 52 eyes in the anterior transposition group). There were no differences in preoperative best corrected visual acuity, amblyopia, spherical equivalent, and primary versus secondary IOOA between the two groups. Both surgical procedures were effective in reducing IOOA and satisfactory results were similar between the two groups: 61.7% and 67.3% in the myectomy and anterior transposition groups, respectively (P = .56). After adjustment for the preoperative DVD, there was no statistically significant difference between the two groups postoperatively. The preoperative hypertropia was 6 to 14 and 6 to 18 prism diopters (PD) in the myectomy and anterior transposition groups, respectively. After surgery, no patient had a vertical deviation greater than 5 PD. Both the inferior oblique myectomy and anterior transposition procedures are effective in reducing IOOA with similar satisfactory results. DVD and hypertropia were also corrected similarly by these two surgical procedures. [J Pediatr Ophthalmol Strabismus. 2017;54(4):232-237.].

Equatorial Scleral Anchor for the Weakening of the Inferior Oblique Muscle

Objective: The study was conducted to evaluate the mid-term effectiveness of a new surgical approach in the reduction of overaction of the inferior oblique muscle. Methods: A new surgical treatment was developed consisting of suturing the muscle to the sclera at the Gobin’s point with tendon sparing by way of a micro-incision to reduce any tissue damage during the surgical procedure and to enhance the healing process. The treatment was evaluated postoperatively in a group of 150 patients with primary or secondary inferior oblique overaction. Results: All patients experienced a complete resolution of the elevation in adduction, no residual vertical imbalance, lateral incomitance was improved. Conclusion: The outcome of the new equatorial scleral anchor surgical treatment has been generally accepted as favourable in our study, also if compared with the results yielded by the most frequently used anterior transposition of the inferior oblique muscle. The new surgical treatment appears to be a relatively a less invasive, safe, reversible technique, including the potential to perform the procedure with an adjustable suture.

Inferior oblique muscle weakening: is it possible to quantify its effects on horizontal deviations?

Objective. To evaluate and quantify the effect of inferior oblique muscle weakening on horizontal deviations. Methods. The medical files of patients who had undergone an inferior oblique weakening as a single procedure were all reviewed. The main measures were the type of inferior oblique overaction (IOOA), pre- and postoperative amount of IOOA, and horizontal deviations in primary position. Results. The study was conducted with 66 patients (30 males, 36 females). The median age was 11 years (1–49). Of the 66 patients, 30 (45.5%) had primary and 36 (54.5%) had secondary IOOA. The most common procedure was inferior oblique anteriorization in 32 patients (48.5%). The mean postoperative horizontal and vertical deviations and the amount of IOOA were decreased postoperatively (p = 0.001 for all). The median amount of correction of horizontal near and distance deviations was 4Δ (0–20). The preoperative amount of IOOA, the presence of fourth nerve palsy, and the type of the weakening procedure had no significant effect on the amount of correction of horizontal deviations. Conclusion. The inferior oblique weakening procedures have secondary effects and warrant reduction of horizontal deviations in varying degrees. This should be borne in mind in planning a simultaneous horizontal muscle surgery and setting the surgical amount.

The Effect of Inferior Oblique Muscle Z Myotomy in Patients with Inferior Oblique Overaction

To investigate the surgical outcomes of inferior oblique muscle Z myotomy in patients with inferior oblique overaction (IOOA). A prospective study was performed in 21 patients (primary IOOA in 13 patients, secondary IOOA in 8 patients) who underwent inferior oblique muscle Z myotomy. Patients with IOOA under the degree of +2 were included. Seventy percent of Z myotomies were performed at 6 mm along the physiological path after identifying the inferior oblique muscle through an inferotemporal fornix incision. A comparison was made before the operation and 3 months postoperatively on the degree of IOOA, vertical deviation, and cyclotorsion. Simultaneous horizontal rectus surgery was performed with inferior oblique muscle Z myotomy because all patients had combined horizontal deviation. The mean degrees of preoperative and postoperative IOOA were +1.9 ± 0.32 and +0.7 ± 0.67 in the primary IOOA group and +1.83 ± 0.41 and +0.17 ± 0.41 in the secondary IOOA group. Six of 7 patients in the primary IOOA group showed V-pattern strabismus, which was improved in all cases after the operation. In the secondary IOOA group, changes of preoperative and postoperative hypertropia and cyclodeviation were from 7.75 ± 6.64 prism diopters and 8.6 ± 2.31° to 1.2 ± 3.35 prism diopters and 4.7 ± 2.02°, respectively. Inadvertent complete myotomy occurred in 1 patient due to excessive traction by an assistant during the procedure. Inferior oblique muscle Z myotomy was an effective surgical procedure in patients with primary and secondary IOOA under the degree of +2.

Myectomy versus anterior transposition for inferior oblique overaction

Inferior oblique overaction can be either secondary (as a sequela of ipsilateral superior oblique palsy) or primary (commonly associated with horizontal strabismus). Superior oblique underaction often coexists with both primary and secondary inferior oblique overaction. This retrospective case series compares the efficacy of inferior oblique myectomy versus anterior transposition in improving inferior oblique overaction and superior oblique underaction in eyes with either primary or secondary inferior oblique overaction. One hundred twenty eyes of 81 patients were included in this retrospective case series, of which 20 had anterior transposition of the inferior oblique and 100 eyes underwent myectomy. Inferior oblique myectomy was compared with inferior oblique anterior transposition in improving inferior oblique overaction and superior oblique underaction in each diagnostic subgroup. Postoperative outcome was qualitatively and quantitatively assessed. Fisher's exact test was used to compare the outcomes. The quantitative improvement of function in terms of inferior oblique overaction and superior oblique underaction was analyzed by regression analysis. When postoperative inferior oblique overaction was considered, there was no statistically significant difference between myectomy and anterior transposition in both primary and secondary inferior oblique overaction. Myectomy was superior to anterior transposition in improving superior oblique underaction in both primary inferior oblique overaction (OR = 0.14; 95% CI, 0.015-1.45; p = 0.056) and secondary inferior oblique overaction (OR = 0; 95% CI, 0-0.027; p < 0.001). The quantitative improvement of function showed a significant difference between procedures for superior oblique underaction (t-test; p = 0.005; 95% CI, 0.25-1.3) but not inferior oblique overaction (t-test; p = 0.8; 95% CI, -0.67-0.54). This study demonstrates both inferior oblique myectomy and inferior oblique anterior transposition to be effective in correcting primary and secondary inferior oblique overaction. Myectomy is more effective in improving superior oblique underaction associated with both primary and secondary inferior oblique overaction. On this basis, we feel that inferior oblique myectomy has some advantage over anterior transposition in treating combined inferior oblique overaction and superior oblique underaction and can be considered the procedure of choice.

Calcium Uptake and Release through Sarcoplasmic Reticulum in the Inferior Oblique Muscles of Patients with Inferior Oblique Overaction

We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p<0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA.

Inferior oblique surgery. Experience at the Mayo Clinic from 1960 to 1981.

Three hundred thirty-seven patients underwent inferior oblique disinsertions at the Mayo Clinic Rochester, Minn, from 1960 to 1981. Versions and hyperdeviations in the primary position were recorded preoperatively and postoperatively. The criteria of a successful result were (1) correction of diplopia, (2) correction of hyperdeviation in the field of action of the inferior oblique, and (3) correction of versions in adduction. Clinical failure was reflected in persistence of hyperdeviation in primary gaze and persistence of overaction of the inferior oblique muscle in adduction. A successful result was found in 88% of primary inferior oblique disinsertions. For secondary inferior oblique overaction, a successful result was found in 72% of patients. We have found that inferior oblique disinsertion is a safe, fast, reliable, and effective weakening procedure with good results.