The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis

Introduction: Vertical strabismus, commonly caused by the overaction of the inferior oblique (IO) muscle, is a frequent oculomotor disorder. It affects one-third of all patients with strabismus, with 70% of these cases coexisting with esotropia. Currently, there is no universally accepted method fo...

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Main Authors: Masoud Khorrami-Nejad, Huda Karim, Wisam Hatem, Mustafa Abdullah, Ali Gheibi, Mohammad Ghasemi Boromand
Format: Article
Language:English
Published: Tehran University of Medical Sciences 2024-11-01
Series:Journal of Modern Rehabilitation
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Online Access:https://jmr.tums.ac.ir/index.php/jmr/article/view/884
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author Masoud Khorrami-Nejad
Huda Karim
Wisam Hatem
Mustafa Abdullah
Ali Gheibi
Mohammad Ghasemi Boromand
author_facet Masoud Khorrami-Nejad
Huda Karim
Wisam Hatem
Mustafa Abdullah
Ali Gheibi
Mohammad Ghasemi Boromand
author_sort Masoud Khorrami-Nejad
collection DOAJ
description Introduction: Vertical strabismus, commonly caused by the overaction of the inferior oblique (IO) muscle, is a frequent oculomotor disorder. It affects one-third of all patients with strabismus, with 70% of these cases coexisting with esotropia. Currently, there is no universally accepted method for quantifying the magnitude of IO overaction (IOOA), as existing classifications are subjective and may not be entirely appropriate. Standardization of IOOA classification is crucial to better understand its severity, develop effective treatment strategies, and predict surgical outcomes. The mechanism of action of the IO muscle is complex and varies with the globe's position during contraction. Beyond horizontal and vertical movements, the IO muscle also contributes to torsional eye movements, impacting the diagnosis and treatment of vertical strabismus and cyclotropia. Materials and Methods: The biomechanical properties of the IO muscle and its triple-action characteristics (horizontal, vertical and torsional movements) were analyzed. A review of current diagnostic practices was conducted, emphasizing the need for comprehensive clinical examinations to identify the signs and symptoms of IOOA and determine its severity. Results: Disorders of the IO muscle often result in vertical strabismus and cyclotropia, complicating strabismus treatment. The variability of the IO muscle's mechanism of action highlights the inadequacy of subjective classification systems. Incorporating the triple-action characteristics of the IO muscle into diagnostic evaluations enables a more accurate understanding of IOOA and its clinical manifestations. Conclusion: Standardizing the classification of IOOA is essential for accurately assessing its severity, guiding treatment strategies, and predicting surgical outcomes. Comprehensive diagnostic examinations that consider the triple-action nature of the IO muscle are necessary to improve the management and treatment of patients with IOOA.
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spelling doaj-art-7e65eb378fc84d14bfde11800e4815c52025-02-09T09:07:32ZengTehran University of Medical SciencesJournal of Modern Rehabilitation2538-385X2538-38682024-11-0119110.18502/jmr.v19i1.17505The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and DiagnosisMasoud Khorrami-Nejad0Huda Karim1Wisam Hatem2Mustafa Abdullah3Ali Gheibi4Mohammad Ghasemi Boromand5Translational Ophthalmology Research Center, Farabi Hospital, Tehran University of Medical Sciences, Tehran, Iran.Department of Optometry, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.Department of Optometry, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.Department of Optometry, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.Student Research Committee. Department of Optometry, Faculty of Rehabilitation, Shahid Beheshti University of Medical Sciences. Tehran. Iran.Department of Optometry, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Introduction: Vertical strabismus, commonly caused by the overaction of the inferior oblique (IO) muscle, is a frequent oculomotor disorder. It affects one-third of all patients with strabismus, with 70% of these cases coexisting with esotropia. Currently, there is no universally accepted method for quantifying the magnitude of IO overaction (IOOA), as existing classifications are subjective and may not be entirely appropriate. Standardization of IOOA classification is crucial to better understand its severity, develop effective treatment strategies, and predict surgical outcomes. The mechanism of action of the IO muscle is complex and varies with the globe's position during contraction. Beyond horizontal and vertical movements, the IO muscle also contributes to torsional eye movements, impacting the diagnosis and treatment of vertical strabismus and cyclotropia. Materials and Methods: The biomechanical properties of the IO muscle and its triple-action characteristics (horizontal, vertical and torsional movements) were analyzed. A review of current diagnostic practices was conducted, emphasizing the need for comprehensive clinical examinations to identify the signs and symptoms of IOOA and determine its severity. Results: Disorders of the IO muscle often result in vertical strabismus and cyclotropia, complicating strabismus treatment. The variability of the IO muscle's mechanism of action highlights the inadequacy of subjective classification systems. Incorporating the triple-action characteristics of the IO muscle into diagnostic evaluations enables a more accurate understanding of IOOA and its clinical manifestations. Conclusion: Standardizing the classification of IOOA is essential for accurately assessing its severity, guiding treatment strategies, and predicting surgical outcomes. Comprehensive diagnostic examinations that consider the triple-action nature of the IO muscle are necessary to improve the management and treatment of patients with IOOA. https://jmr.tums.ac.ir/index.php/jmr/article/view/884Vertical strabismusInferior oblique overactionStrabismusOverelevation
spellingShingle Masoud Khorrami-Nejad
Huda Karim
Wisam Hatem
Mustafa Abdullah
Ali Gheibi
Mohammad Ghasemi Boromand
The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
Journal of Modern Rehabilitation
Vertical strabismus
Inferior oblique overaction
Strabismus
Overelevation
title The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
title_full The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
title_fullStr The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
title_full_unstemmed The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
title_short The Overaction of the Inferior Oblique Muscle and Associated Vertical Strabismus: Prevalence, Etiology and Diagnosis
title_sort overaction of the inferior oblique muscle and associated vertical strabismus prevalence etiology and diagnosis
topic Vertical strabismus
Inferior oblique overaction
Strabismus
Overelevation
url https://jmr.tums.ac.ir/index.php/jmr/article/view/884
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