Extraocular muscles (EOMs) are the most molecularly heterogeneous and physiologically diverse mammalian striated muscles. They express the entire array of striated muscle myosins, including a specialized myosin heavy chain MYH13, which is restricted to extraocular and laryngeal muscles. EOMs also exhibit a breadth of contractile activity, from superfast saccades to slow tracking and convergence...

The sarcomere is the major structural and functional unit of striated muscle. Approximately 65 different proteins have been associated with the sarcomere, and their exact composition defines the speed, endurance, and biology of each individual muscle. Past analyses relied heavily on electrophoretic and immunohistochemical techniques, which only allow the analysis of a small fraction of proteins...

PURPOSE To describe the clinical features of a Caucasian female patient with a history of treated gastrointestinal Whipple's disease (WD) who developed new-onset diplopia, with a description of the histopathological features of the extraocular muscle biopsies. METHODS A previously fit 38-year-old Caucasian female presented with acute-onset diplopia after being on a sustained medication regime...

Recent anatomical studies of extraocular muscles (EOM) demonstrate the stability of muscle paths. This is due to the fact that each rectus EOM passes through a pulley consisting of an encircling ring or sleeve of collagen. In this paper, the EOMs are modeled using the Hill type musculotendon complex and the effect of extraocular pulleys are studied. The model proposed by Martin and Schovanec in...

INTRODUCTION Injury is a known cause of monocular blindness. Ocular trauma may affect lacrimal canaliculi and the extraocular muscle. We report this case as it includes injury to lid, lacrimal canaliculi and inferior rectus. CASE DESCRIPTION A 25-year-old male presented with an injury caused by a sharp object that resulted in a conjunctival tear, lid tear involving the lacrimal canal, and rup...

It has long been known that the striated muscle fibres of which the extraocular muscles are composed differ in many respects from skeletal muscle in general. Their relatively small size, rich innervation, their small motor units and the presence of a proportion of fibres with multiple endplates are special characteristics which are recounted in most modern texts of ophthalmology. There are thre...

PURPOSE Embryonic eyelid closure is a well-documented morphogenetic episode in mammalian eye development. Detection of eyelid closure defect in humans is a major challenge because eyelid closure and reopen occur entirely in utero. As a consequence, congenital eye defects that are associated with failure of embryonic eyelid closure remain unknown. To fill the gap, we developed a mouse model of d...

The extraocular muscles of dystrophic mouse strain Re-129 dy/dy were studied in combined phase and electron microscopy. Changes in fiber morphology were found which are similar to those described in dystrophic human and mouse peripheral musculature, i.e., changes in fiber diameter, alteratiotxs in the cellular organelles, including mitochondria, sarcoplasmic reticulum, nuclei, sarcolemma, and l...

PURPOSE PITX2 gene dose plays a central role in Axenfeld-Rieger syndrome. The purpose of this study was to test the hypothesis that the effects of Pitx2 gene dose on eye development can be molecularly dissected in available Pitx2 mutant mice. METHODS A panel of mice with Pitx2 gene dose ranging from wild-type (+/+) to none (-/-) was generated. Eye morphogenesis was assessed in animals with ea...

PURPOSE To characterize the relationship between inflammation and swelling of extraocular muscles in thyroid-associated ophthalmopathy before and after methylprednisolone pulse therapy. METHODS The signal intensities and volumes of the superior rectus (SR), inferior rectus (IR), lateral rectus (LR), medial rectus (MR), and superior oblique (SO) muscles were measured with magnetic resonance im...