Objectives: To assess the degree of correction in SUPERIOR OBLIQUE OVER ACTION in A pattern strabismus, atypical Brown's syndrome, and monocular elevation deficiency syndrome by the graduated SUPERIOR OBLIQUE recession.Methods: This interventional case series comprised 10 patients (12 eyes) with an indication for SUPERIOR OBLIQUE weakening. According to the grade of muscle OVER ACTION, forced duction test result, A-pattern and in torsion, and via a SUPERIOR temporal approach the SUPERIOR OBLIQUE tendon was transposed 10-12 mm posterior to the limbos and 1-4 mm medial to the insertion of the SUPERIOR rectos. The patients were followed up for at least 6 weeks post operation. Results: Ten patients aged 6-22 years (6 females and 4 males) underwent the operation. The A-pattern was corrected 94%. The OVER ACTION, vertical deviation and the forced duction test were reduced by less than half in cases of atypical Brown's and monocular elevation deficiency syndromes. The improvement was significant in the 2 cases of DVD with an OVERacting SUPERIOR OBLIQUE. Conclusion: The graduated recession of the SUPERIOR OBLIQUE is an appropriate procedure for weakening the muscle and is adjustable to the grade of muscle OVER ACTION, A-pattern and in torsion.

Purpose: To compare the efficacy of inferior OBLIQUE myectomy and anterior transposition for correcting Inferior OBLIQUE OVER ACTION (IOOA) and DVD.Methods: This retrospective study was carried out on patients with IOOA who had either myectomy or anterior transposition of the inferior OBLIQUE muscle from 2010 to 2015. The authors compared pre-operative and post-operative inferior OBLIQUE muscle function grading (-4 to+4) as the main outcome measure; vertical and horizontal deviation, dissociated vertical deviation (DVD), and A V-pattern between the two surgical groups as secondary outcomes.Results: 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=0.56). After adjustment for the pre-operative DVD, there was no statistically significant difference between the two groups post-operatively. The pre-operative 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.Conclusion: 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.

Purpose: To report the familial occurrence of congenital SUPERIOR OBLIQUE palsy. Methods: Eight patients from 3 families (A, B, C) with congenital SUPERIOR OBLIQUE palsy were studied. One patient of each family came to the clinic due to ocular deviation and head tilt. Considering the history of similar disease in the family, all available family members had thorough eye examinations. Congenital SUPERIOR OBLIQUE palsy was diagnosed according to “alternate prism cOVER” and “Bielschowsky head tilt” test results and presence of symptoms since childhood and no incidence of blows to the head. Results: In family “A”, the father and his two children had congenital SUPERIOR OBLIQUE palsy on the left side. One of the father’s sisters also had a history of tilting her head to the right, but was not available for examination. In family “B”, three patients of 2 consecutive generations suffered from unilateral congenital SUPERIOR OBLIQUE palsy. The grandfather and another man from this family also had a history of tilting the head, but were not available for examination. In family “C”, the mother and her daughter had congenital SUPERIOR OBLIQUE palsy on the left side. Four of these patients were operated on by the authors. None of them showed signs of marked laxity or absence of SUPERIOR OBLIQUE tendon. In families “A” and “B”, the transmission of the disease by autosomal dominant was seen. Conclusions: It is necessary to consider genetic transfer in any patient suffering from congenital SUPERIOR OBLIQUE palsy and therefore family members need to be examined.  

Purpose: Report of simultaneous 10 and SO weakening procedure in treatment of DVD with SO OVERACTION.Method: 2 patients with DVD and SUPERIOR OBLIQUE OVERACTION (SOOA) underwent recession and posterior transposition of SO muscle and anteriorization of 10 muscles in the involved eye. They have been followed for 6 months after operation.Results: The first patient with 1/10 visual acuity in the right eye and extra foveal fixation, 35PD R HT in Primary Position (PP), +3 SOOA in involved eye after operation, deviation decreased to 5PDR HT in PP and +1 SOOA but -2 Inferior OBLIQUE UnderACTION (IOUA) has been found in that eye.In the second patient with 7/10 visual acuity in right eye, 7PDR HT in PP and +2 R SOOA in the involved eye have neither HT in PP nor SOOA after operation.Conclusion: Simultaneous IO and SO weakening procedure can be suitable for DVD and SO.OA treatment but we suggest in eyes with poor vision, SO graded recession must be more than graded IO recession to prevent IOUA.

Purpose: To evaluate the effect of Botulinum toxin-A (BTA) injection into the inferior OBLIQUE (IO) muscle in releaving the symptoms of SUPERIOR OBLIQUE (SO) palsy.Methods: The study was conducted on patients who were referred for acquired SO palsy with less than 2 years of duration. About 10-20 unit of BTA was injected into the belly of the inferior OBLIQUE muscle through the inferotemporal quadrant of the involved eye without opening the conjunctiva.Results: Eighteen eyes from 16 patients were injected. Mean age was 33.7 years and mean duration of paresis was 6 months. Trauma was the cause of paresis in 81.2%. Six months after the injection, mean deviation decreased from 6.4D to 1.9D; mean IO OVER-activity decreased from +1.7 to +0.6; mean SO upper-activity decreased from -1.5 to -0.4; mean subjective torsion decreased from 9.30 to 0.40; and mean head tilt decreased from 8.40 to 1.10.Conclusion: Botulinum toxin-A injection into the IO muscle can decrease the symptoms of patients with SO palsy and cause faster rehabilitation of these patients before stabilization of signs for final decision.

Purpose: We describe clinical and radiologic findings and surgical outcome of an orbital dermoid cyst located in the SUPERIOR OBLIQUE muscle tendon. This unusual location for dermoid tumors has not been reported previously.Case report: A 15-year-old girl referred to us with an orbital mass in superonasal quadrant of the left orbit reportedly to be present from birth. Computed tomography revealed a cystic mass in the superonasal quadrant of the left orbit. Surgical excision through an incision at the medial of the upper lid crease showed two well-circumscribed masses surrounded by SUPERIOR OBLIQUE muscle tendon. Results of histopathologic evaluation showed a dermoid cyst. Postoperatively, the patient did well with no change in her clinical finding.Conclusion: The findings in this patient demonstrate an unusual presentation for dermoid cysts; such pathologies could be included in the differential diagnosis of an enlarged extraocular muscle (EOM).

Purpose: To report a case of concurrent congenital SUPERIOR OBLIQUE palsy and Axenfeld Rieger syndrome.Patient and findings: A 28-year-old man was referred for head tilt since early childhood. On physical examination, there was right hypertropia that increased with gaze to left and head tilt to right. Examination of the anterior segment showed prominent and anteriorly displaced Schwalbe's ring to which multiple peripheral iris strands adhered. Corectopia was present in the right eye. The diagnosis was congenital right SUPERIOR OBLIQUE palsy and Axenfeld Rieger syndrome. Conclusion: Since neural crest cells eventually differentiate to produce tendons and sheaths of extra ocular muscles and Axenfeld Rieger syndrome is due to abnormalities of these cells in the embryonic period, the hypothesis that one common factor may have induced both entities in the patient is strongly suggested.

Flow discharge OVER an OBLIQUE weir is greater than that OVER a straight or plain weir for the same water head due to its extra length with respect to the channel width or fully extended plain weir. In this study, a new theoretical approach is used for the hydraulics of OBLIQUE weirs. The main objective is to investigate the effect of different hydraulic and geometric properties of the flow and the weir on the flow deflection angle and discharge coefficients for free and submerged flow OVER OBLIQUE weirs. This approach is based on energy, momentum and continuity equations. For improving the performance of this kind of weir, one approach is to increase the flow deflection until it is perpendicular to the OBLIQUE weir for maximum use of the weir length. The submerged guide vanes have also been used and investigated theoretically. The data for calibration of the models are taken from Borghei et al. (2003). It is shown that by employing guide vanes, for some cases, the discharge coefficient can be increased up to 33%. Finally, new relations were developed for practical purposes.