Muscle Overaction Research Articles

The Incidence of Reoperation and Related Risk Factors Among Patients With Infantile Exotropia.

To determine the incidence and related risk factors of reoperation among patients with infantile exotropia who were operated on at Imam Hossein Medical Center, Tehran, Iran, from 2001 to 2015. In this study, 82 children (55 girls and 27 boys) with infantile exotropia were divided into two groups 3 months after their first operation: children with horizontal deviation of 10 prism diopters (PD) or less (n = 64; success group) and those with horizontal deviation greater than 10 PD (n = 18; failure group). Patients with deviation of 20 PD or greater were indicated for reoperation. Factors including age at the first operation, preoperative angle of deviation, inferior oblique muscle overaction, dissociated vertical deviation, and A- or V-pattern in relation to reoperation were studied. Sensory status of children older than 5 years was also evaluated using Worth 4-dot and Titmus tests. Reoperation was indicated in 18.3% (n = 15) of patients after 11.5 ± 19 months of follow-up. Preoperative angle of deviation (P < .001) and surgical approach (P = .017) were statistically different between the failure and success groups. The majority of patients (71%) achieved fusion and gross stereopsis (< 3,000 seconds of arc) after surgery. According to the results, 18.3% of patients with infantile exotropia, especially those with more preoperative exotropia, needed reoperation to achieve good alignment. Although the recession-resection method had better motor results, the authors could not recommend it as a first operation for all patients with infantile exotropia because it was only performed on patients with amblyopia. Gross stereopsis and binocular fusion were seen in the majority of patients. [J Pediatr Ophthalmol Strabismus. 2017;54(1):22-30.].

Posición primaria de la mirada en hiperfunción de oblicuos inferiores con y sin desviación vertical disociada

IntroductionWhen dissociated vertical deviation (DVD) is associated with vertical action muscles overaction, it is very important to define which part of the vertical deviation is due to the DVD and which one due to the overaction by itself, especially in the indication of surgical treatment (selection muscles and surgical technique to be used). The primary position (PP) may be different in inferior oblique muscle overaction when it's associated to DVD and it can be a clinical data which allows us to identify it. ObjectiveDemonstrate what is the PP in patients with inferior oblique muscle overaction with or without DVD. MethodsObservational, transversal and comparative study, it was included patients with inferior oblique muscle overaction with or without DVD of the strabismus service; a complete ophthalmological examination was performed. For statistical analysis Fisher's exact test was used. ResultsThere were in total 46 patients. 24 patients (52.17%) had DVD. The PP found in patients with overactive inferior oblique and DVD: double hypertropia in 14 (58.33%), hyper-hypotropia 8 (33.33%), and 2 patients in orto-position (8.33%). In patients with overactive inferior oblique without DVD, the PP was hyper-hypotropia found in 19 (86.36%) and 3 patients orto-position (13.64%). Findings statistically significant (p<0.05). ConclusionsIn patients with inferior oblique muscle overaction with DVD prevails double hypertropia in the PPM and in patients with inferior oblique muscle overaction without DVD prevails hyper-hypotropia, with a statistically significant difference.

Intermittent exotropia with a positive Bielschowsky head-tilt test.

To investigate the clinical features of patients with intermittent exotropia (IXT) with and without positive Bielschowsky head-tilt test (BHTT), but without superior oblique palsy. We retrospectively reviewed the charts of 118 patients with IXT. Patients were divided into two groups according to positive or negative BHTT. Associated risk factors for positive BHTT in patients with IXT were analysed. The changes in the BHTT result after surgery were also analysed. Fifty patients showed a positive BHTT, and 68 patients showed a negative BHTT. There were significant differences between the groups with regard to the elapsed time from the onset of IXT, the angle of distance exodeviation, inferior oblique muscle overaction, vertical deviation at the primary position, suppression and stereoacuity (all for p<0.05). Risk factors for a positive BHTT among patients with IXT were the elapsed period since the onset of IXT (OR, 1.034; 95% CI 1.008 to 1.061, p=0.011), angle of distance exodeviation (OR, 1.087; 95% CI 1.015 to 1.165, p=0.017) and near stereoacuity (OR, 1.006; 95% CI 1.001 to 1.011, p=0.029). Horizontal muscle surgery alone, without cyclovertical muscle surgery, resulted in a significant decrease in the number of patients with positive BHTT (p<0.01). A positive BHTT was seen in patients with IXT with larger angle exodeviations, longer elapsed time periods since the onset of IXT and worse stereoacuity. The positive BHTT could be eliminated using horizontal muscle surgery only, without complementary inferior oblique muscle weakening surgery.

Effect of operation time on the treatment of children with congenital internal strabismus

Objective To investigate the surgery opportunity choice of congenital esotropia. Methods A retrospective research was taken using the clinical data and the results of the treatment of 146 inpatients with congenital esotropia in our department from Mar 2012 to Mar 2015. The correction rate, lacking-correction rate, and over-correction rate were compared between early surgery group and late surgery group on time of 1 week after surgery and 6 months after surgery, respectively. Results In all the 146 patients, 88 (60.3%) had an esotropia deviation greater than or equal to 40 pupil distance (PD), 38 (26.0%) combined with amblyopia, 12 (8.2%) combined with nystagmus, 30 (20.5%) combined with inferior oblique muscle overaction, 6(4.1%) combined with dissociated vertical divergence (DVD). There was no significant difference between early surgery group and late surgery group on correction rate, lacking-correction rate, and over-correction rate on the time of 1 week after surgery and 6 months after surgery, respectively. Conclusions Congenital strabismus should take surgery at the early-stage, especially for those have large angles. It is better to be operated before 2-year old for a better formation and recovery of binocular visual function. Key words: Esotropia/SU

Inferior Oblique Botulinum Toxin Injection: A Postoperative Diplopia Test for Secondary Inferior Oblique Muscle Overaction.

To evaluate the utility of botulinum toxin injection into the inferior oblique muscle for secondary inferior oblique muscle overaction. A retrospective review of 18 patients and 23 injections performed over a 9-year period. Indications and deviations in primary position and contralateral gaze before and after injection were recorded. Functional outcomes and further management (conservative vs surgical) were observed. In 14 patients, chemodenervation resulted in a temporary improvement in symptoms. Eleven of these patients went on to have inferior oblique myectomy with resolution of their diplopia. Two patients preferred to receive regular injections of botulinum toxin as a treatment. Botulinum toxin chemodenervation of the inferior oblique muscle in cases of secondary inferior oblique muscle overaction is useful where one needs to establish a risk of overcorrection following planned inferior oblique muscle weakening. This is particularly true in cases where the primary position deviation may be small but symptoms of diplopia exist on contralateral side gaze, giving rise to a narrowed field of binocular single vision.

Deficiency of depression in adduction: clinical characteristics and surgical management of the “inverted Brown pattern”

To evaluate the clinical characteristics and surgical management of patients with an "inverted Brown pattern," which is defined clinically as a hypertropia with greatest deviation in down-and-in gaze of the higher eye, having the appearance of superior oblique muscle underaction but without significant inferior oblique muscle overaction. The medical records of patients with this misalignment pattern who had cyclovertical muscle surgery at our institution from 2003 through 2015 were retrospectively reviewed; medical records were analyzed for pre- and postoperative motility patterns, fundus torsion, intraoperative findings, and type of strabismus surgery. A total of 45 patients presenting with a hyperdeviation worse in down-and-in gaze of the higher eye were included in the study. Of these, 25 (56%) had previously had inferior oblique-weakening procedures. The remainder included those with untreated superior oblique paresis (22%), previous orbital trauma (18%), or other ocular surgery (4%). The mean preoperative hyperdeviation in straight-ahead gaze was 8.7(Δ), compared with 0.9(Δ) postoperatively. Surgical success, defined as the absence of diplopia in straight-ahead gaze and not requiring further cyclovertical surgery, was achieved in 78% of patients. The motility pattern referred to as the "inverted Brown pattern" can develop in patients with orbital trauma, as previously described, or in association with superior oblique muscle paresis, most commonly after prior surgery to weaken the inferior oblique muscle. Weakening or reweakening of the inferior oblique muscle appears to correct this misalignment pattern, despite the absence of significant inferior oblique overaction preoperatively.

Alt Oblik Kas Hiperfonksiyonu Tedavisinde Alt Oblik Kas Geriletmesi ve Miyektomi Yöntemlerinin Karşılaştırılması

Amaç: Primer ve sekonder alt oblik kas hiperfonksiyonu (AOHF) düzeltilmesinde kullanılan alt oblik kas geriletmesi ve miyektomi yöntemlerinin sonuçlarının karşılaştırılmasıdır. Gereç ve Yöntemler: Ocak 2007-Aralık 2014 tarihleri arasında farklı derecelerde AOHF nedeniyle alt oblik kas zayıflatma cerrahisi uygulanan 74 hastanın 120 gözü bu retrospektif çalışmaya dâhil edildi. Hastaların demografik özellikleri, uygulanan cerrahi türü, cerrahi öncesi ve sonrası AOHF derecesi, eşlik eden horizontal kayma ve komplikasyonlar kaydedildi. Hastaların takip süresi medyan değeri 22 ay idi. Cerrahi sonrası AOHF'nin tamamen ortadan kalkmasında standart başarı kriterinin +1 düzeyinde olması ise sınırlı başarı kriteri olarak belirlendi. Bulgular: Hastaların medyan yaşı 7,0 yıl (1,0-32,0), medyan takip süresi 22,0 ay (1,0-81,0) idi. Kırk dokuz (%62,6) hastada primer AOHF, 25 (%33,8) hastada ise sekonder AOHF mevcuttu. Altmış üç (%52,5) göze alt oblik kas miyektomisi, 57 (%47,5) göze alt oblik kas geriletmesi yapıldı. Standart başarı oranları miyektomi için %82,5, geriletme için %82,4 idi. Miyektomi yapılan gözlerin %12,7'sinde, geriletme yapılan gözlerin %10,5'inde sınırlı başarıya ulaşıldı. Hastaların cerrahi öncesi ve sonrası AOHF düzeylerindeki fark yönünden miyektomi ve geriletme yöntemleri arasında anlamlı fark saptanmadı (p=0,163). Cerrahi sonrası toplam 14 (sekiz göze miyektomi, altı göze geriletme yapılmış) gözde nüks ve 2 (ikisine de miyektomi yapılmış) gözde adezyon sendromu geliştiği gözlendi. Başka bir komplikasyon izlenmedi. Sonuç: Primer ve sekonder AOHF tedavisinde uygulanan alt oblik kas miyektomi ve geriletme yöntemleri etkili ve güvenilir yöntemlerdir. Her iki yöntem de benzer başarı oranlarına sahiptir. Tekrar cerrahi ihtiyacı olan hastalarda geriletme yönteminin avantajı kasa daha kolay ulaşılmasını sağlamasıdır.

Comment on ′Outcomes of asymmetric primary inferior oblique muscle overaction managed by bilateral myectomy and tucking of proximal muscle end: A cohort study′

Comment on ′Outcomes of asymmetric primary inferior oblique muscle overaction managed by bilateral myectomy and tucking of proximal muscle end: A cohort study′

Extraocular Muscles Tension, Tonus, and Proprioception in Infantile Strabismus: Role of the Oculomotor System in the Pathogenesis of Infantile Strabismus-Review of the Literature.

The role played by the extraocular muscles (EOMs) in the etiology of concomitant infantile strabismus is still debated and it has not yet definitively established if the sensory anomalies in concomitant strabismus are a consequence or a primary cause of the deviation. The commonest theory supposes that most strabismus results from abnormal innervation of the EOMs, but the cause of this dysfunction and its origin, whether central or peripheral, are still unknown. The interaction between sensory factors and innervational factors, that is, esotonus, accommodation, convergence, divergence, and vestibular reflexes in visually immature infants with family predisposition, is suspected to create conditions that prevent binocular alignment from stabilizing and strengthening. Some role in the onset of fixation instability and infantile strabismus could be played by the feedback control of eye movements and by dysfunction of eye muscle proprioception during the critical period of development of the visual sensory system. A possible role in the onset, maintenance, or worsening of the deviation of abnormalities of muscle force which have their clinical equivalent in eye muscle overaction and underaction has been investigated under either isometric or isotonic conditions, and in essence no significant anomalies of muscle force have been found in concomitant strabismus.

Is Inferior Oblique Overaction Associated With Astigmatism?

To study the relationship between inferior oblique muscle overaction and astigmatism, and to explore any change in astigmatism after surgery. This was a retrospective chart review of patients undergoing strabismus surgery. Demographic data collected included age, diagnosis, preoperative refraction, presence of inferior oblique overaction, surgery performed, and postoperative refraction. Patients were divided into three groups: those having only horizontal strabismus without inferior oblique overaction (no inferior oblique group) as a control group, those having bilateral inferior oblique overaction (bilateral inferior oblique group), and those having unilateral inferior oblique overaction (unilateral inferior oblique group). Right eyes of the bilateral inferior oblique and no inferior oblique groups were chosen for analysis, whereas the eye with inferior oblique overaction was included in the unilateral cases. Refractions were converted to power vector coordinates for comparison. Statistical analysis was performed to compare the power vectors among groups using the no inferior oblique group as controls and to explore any postoperative change in astigmatism. One hundred eighteen patients undergoing strabismus surgery were included (60 males and 58 females; mean age: 11.31 ± 10.59 years). Patients were divided into three groups: those having only horizontal strabismus without inferior oblique overaction (no inferior oblique group; 60 patients) as controls, those having bilateral inferior oblique overaction (bilateral inferior oblique group; 41 patients), and those having unilateral inferior oblique overaction (unilateral inferior oblique group; 17 patients). Preoperatively, there were no differences in astigmatism when comparing eyes with and without inferior oblique overaction. Postoperatively, both the no inferior oblique group and the bilateral inferior oblique group equally showed an increase in with-the-rule cylinder power (P = .02 and .01, respectively). Inferior oblique muscle overaction did not result in an increased prevalence of astigmatism along the axis of the overacting muscle.

Z-myotomy of the inferior oblique for small incomitant hypertropias.

Small hypertropic deviations due to inferior oblique muscle overaction may cause symptomatic diplopia and frustration because incomitant deviations render prism correction unsatisfactory. The several most common surgical options for inferior oblique weakening risk overcorrection of these smaller deviations. In this study we report the results of a "Z-myotomy" of the inferior oblique muscle to correct small incomitant hypertropias due to mildly overacting inferior oblique muscle. The medical records of patients who underwent inferior oblique Z-myotomy at a single center from 2000 to 2005 were retrospectively reviewed. All patients had a mildly overacting inferior oblique (≤+2) and demonstrated fusion. All patients were diplopic, which was the indication for surgery. Pre- and postoperative deviation was measured and ocular motility was assessed. A total of 38 patients were included. Of these, 24 underwent unilateral inferior oblique Z-myotomy; 5, bilateral Z-myotomy; 5, simultaneous contralateral inferior rectus recession; and 4, simultaneous contralateral inferior oblique recession. In most cases the postoperative measurements demonstrated an almost complete "collapse" of the strabismus pattern. On average, a Z-myotomy procedure required 5-7 minutes to perform. There were no intraoperative complications or deviation overcorrections. The inferior oblique Z-myotomy is a straightforward, quick, sutureless procedure. It can serve as an effective alternative weakening procedure for normalization of ductions in cases of minimally overacting inferior oblique muscle with small incomitant hypertropias. The risk for symptomatic overcorrection is very small.

Relationship of inferior oblique overaction to macular and subfoveal choroidal thickness

To evaluate the macular and subfoveal choroidal thickness of eyes with inferior oblique muscle overaction (IOOA) using enhanced depth imaging spectral domain optical coherence tomography (EDI SD-OCT). The measurements of macular and subfoveal choroidal thickness obtained by EDI SD-OCT of patients with IOOA (24 patients) were compared with those of age- and sex-matched controls (25 subjects). There were no morphological abnormalities of the macula in patients with IOOA or in control subjects. There were no statistically significant differences in macular and subfoveal choroidal thickness between the eyes with IOOA and the eyes of the control subjects (P > 0.05). When the patients with IOOA were assigned to two distinct groups according to the degree of IOOA, the macular thickness did not differ between groups (P = 0.66), whereas subfoveal choroidal thickness measures were significantly lower in eyes with severe IOOA compared to eyes of the controls (P = 0.01). IOOA has no effect on the morphology and the thickness of the macula. Severe IOOA seems to be related to thinning of subfoveal choroid due to possible external mechanical effect.

Outcomes of Asymmetric Primary Inferior Oblique Muscle Overaction Managed by Bilateral Myectomy and Tucking of Proximal Muscle End: A Cohort Study.

Background:We present the outcomes of bilateral myectomy and tucking of the proximal end of the muscle for the treatment of asymmetric primary inferior oblique (IO) overaction.Methods:This was a one-armed prospective cohort study. An ophthalmologist and orthoptist evaluated cases of primary IO muscle overaction presenting between January 2010 and December 2013. All eyes underwent bilateral myectomy and tucking of the proximal end of the IO muscle. Data were collected on ocular motility, the angle of deviation, postoperative complications, and status of hypertropia at 6 months postoperatively. The 95% confidence intervals (CI) were calculated. The statistical significance was indicated by P < 0.05.Results:The patient cohort was comprised of 51 patients with primary IO muscle overaction. Preoperatively, all eyes had +2 or greater overaction of the IO muscle except one patient with +1 and +3 overaction in the right and left eyes, respectively. At 6 months postoperatively, the reduction in the angle of deviation for distance and near was 32.6 prism diopters (PD) ([95% CI 30.3–34.9], P < 0.001) and 32.6 PD ([95% CI: 29.8–35.3], P < 0.001), respectively. There was no significant difference in the postoperative variation of the reduction in the angle of deviation based on gender, right or left eye, and type of horizontal strabismus. There were no cases of “A” or “V” patterns, clinically a significant IO underaction or “adherence syndrome” postoperatively.Conclusion:Bilateral myectomy and tucking of the proximal end of the muscle is likely an effective method of treating asymmetric primary IO muscle 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. J Korean Ophthalmol Soc 2015;56(3):413-419

New surgical intervention for the weakening of the inferior oblique muscle: equatorial scleral anchor.

To evaluate the efficacy of a new surgical technique in reducing inferior oblique muscle overaction. Anterior transposition and myectomy of the inferior oblique muscle represent the gold-standard treatment in dissociated vertical deviation, including cases in which a simultaneous inferior oblique muscle overaction is also present. A new surgical procedure that consists of suturing the muscle to the sclera at the Gobin point with tendon sparing using a micro-incision to minimize the related tissue trauma and induce a faster recovery was developed. Two of 8 patients with essential infant esotropia had a complete resolution of the elevation in adduction with no residual vertical imbalance. All patients experienced an improvement in lateral incomitance. The new "equatorial scleral anchor" surgical procedure gives a similarly good outcome when compared with the classic inferior oblique anterior transposition technique, with the advantages being simple, safe, reversible, and modular in terms of suturing.

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. J Korean Ophthalmol Soc 2015;56(9):1424-1431

An Objective Photographic Analysis of Ocular Oblique Muscle Dysfunction

To develop a new objective method for measuring ocular oblique muscle dysfunction. Prospective, observational study. Twelve healthy volunteers and 27 patients with oblique muscle overaction or underaction in at least 1 eye were included. The corneal contour in 9-gaze photographs was transcribed into an ellipse. A newly developed simulating program depicted the corneal contour as the eyes moved, and graded oblique muscle dysfunction by analyzing the angular difference between the 2 eyes. An angular difference of 5 degrees was defined as 1 unit of overaction or underaction. To verify the accuracy of the method, a masked observer compared the photographic analysis with goniometric readings in the model eye and magnetic search coil recordings in healthy volunteers. The diagnostic accuracy of the photographic analysis was compared with the clinical gradings of patients with oblique muscle overaction or underaction. There was no statistical difference between photographic analysis and goniometric readings of the model eye. Bland-Altman plots showed that there was no overall tendency for the photographic analysis to differ from the scleral search coil values, and the difference fell mostly within ±7 degrees. There was a good correlation between the photographic analysis and the clinical grading of oblique muscle dysfunction (R(2)= 0.618; P< .001). The sensitivity and specificity for detecting oblique muscle overaction were 90.2% and 88.1%, respectively, whereas those for detecting underaction were 81.5% and 80.2%, respectively. A newly developed photographic analysis could provide an objective and accurate means of evaluating ocular oblique muscle dysfunction.

Quantitative Assessment of Inferior Oblique Muscle Overaction Using Photographs of the Cardinal Positions of Gaze

To report a novel method for measuring the degree of inferior oblique muscle overaction and to investigate the correlation with other factors. Cross-sectional diagnostic study. One hundred and forty-two eyes (120 patients) were enrolled in this study. Subjects underwent a full orthoptic examination and photographs were obtained in the cardinal positions of gaze. The images were processed using Photoshop and analyzed using the ImageJ program to measure the degree of inferior oblique muscle overaction. Reproducibility or interobserver variability was assessed by Bland-Altman plots and by calculation of the intraclass correlation coefficient (ICC). The correlation between the degree of inferior oblique muscle overaction and the associated factors was estimated with linear regression analysis. The mean angle of inferior oblique muscle overaction was 17.8 ± 10.1 degrees (range, 1.8-54.1 degrees). The 95% limit of agreement of interobserver variability for the degree of inferior oblique muscle overaction was ±1.76 degrees, and ICC was 0.98. The angle of inferior oblique muscle overaction showed significant correlation with the clinical grading scale (R = 0.549, P < .001) and with hypertropia in the adducted position (R = 0.300, P = .001). The mean angles of inferior oblique muscle overaction classified into grades 1, 2, 3, and 4 according to the clinical grading scale were 10.5 ± 9.1 degrees, 16.8 ± 7.8 degrees, 24.3 ± 8.8 degrees, and 40.0 ± 12.2 degrees, respectively (P < .001). We describe a new method for measuring the degree of inferior oblique muscle overaction using photographs of the cardinal positions. It has the potential to be a diagnostic tool that measures inferior oblique muscle overaction with minimal observer dependency.

Inferior oblique muscle anteriorization in congenital superior oblique palsy.

Inferior oblique muscle overaction of variable amounts is usually present with congenital superior oblique palsy. Inferior oblique muscle anteriorization has been described as a suitable surgical procedure in this entity. The aim of this study was to investigate the effect of inferior oblique muscle anteriorization in patients with congenital superior oblique palsy on vertical, torsional and horizontal alignment. The study was designed as an institutional retrospective cohort study. 45 patients with congenital superior oblique palsy (15 female, 30 male; mean age 36 years ± 19.2 SD, ranging from 6 to 75 years) underwent inferior oblique muscle anteriorization between 2000 and 2010. Preoperative amounts of vertical, torsional and horizontal deviation (using Harms tangent screen), measurements of Bielschowsky head tilt phenomenon as well as stereopsis (Lang test) were compared with findings three months and one year postoperatively. Preoperative vertical deviation in primary position measured 10.1° (mean; range 0-19). Three months postoperatively vertical deviation was significantly reduced (p<0.001) to 4° (mean; range 0-20). After one year vertical deviation measured 3.5° (mean; range 0-15). The values three months postoperatively did not significantly differ from those one year postoperatively (p=0.46). Inferior oblique muscle anteriorization leads to a significant and sustained improvement of ocular alignment in patients with congenital superior oblique palsy of various degrees of severity. Thus the procedure is recommendable as a first line treatment in this clinical situation.

Surgical treatments in inferior oblique muscle overaction.

Purpose:To compare the outcomes of surgical procedures in the treatment of inferior oblique muscle overaction (IOOA) as a common disorder of ocular motility.Methods:This retrospective study was performed on patients with primary and secondary IOOA who underwent three surgical treatment procedures including disinsertion, myectomy and anterior transposition, between 2001 and 2011. Type of strabismus, ocular alignment, presence of pre-and post-operative dissociated vertical deviation (DVD), pre- and post-operative degree of IOOA were obtained using specified checklist.Results:A total of 122 eyes of 74 patients with mean age of 13 ± 11.7 (range, 1-51) years were included in this study. Disinsertion was performed on 12 eyes (9.8%), myectomy in 91 eyes (74.6%) and anterior transposition in 19 (15.6%). Preoperative V-pattern and DVD existed in 67 and 17 eyes; after surgery they remained in only 10 and 8 eyes, respectively. The success rate (IOOA <+1), in disinsertion, myectomy and anterior transposition groups were 91.7%, 97.8%, and 89.5%, respectively and these measures did not change after 6 months. Overall, 53.3% (n = 65) and 38.5% (n = 47) of eyes had preoperative esotropia and exotropia. Preoperative hypertropia and hypotropia were observed in 16.4% (n = 20) and 3.3% (n = 4) of eyes, respectively. After surgery there were no cases of additional strabismus. However, residual hypertropia was seen in 9 eyes, while preoperative hypotropia increased in one patient who underwent anterior transposition surgery. Esotropia and exotropia were not observed in any surgical treatment groups postoperatively.Conclusion:We conclude that all these three procedures are effective for treatment of primary or secondary IOOA with minimum side-effects.