Ultrastructural Studies of Extraocular Muscles in Ocular Motility Disorders

Berard-Badier, M; Pellissier, J. F.; Toga, M; Mouillac, N.; Berard, P V

doi:10.1007/978-3-642-81300-9_18

Cited by 10 publications

(13 citation statements)

References 17 publications

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“…Ultrastructural data on the innervation of the EOM of strabismic patients indicate that the motor nerve endings, mainly located in the body (venter) of the muscle, have normal features [12][13][14], Conversely, all the proprio ceptors located at the scleral myotendinous junction have been found to be altered, both in the presence and the absence of their nerve component [15]. Ultrastructural data on mus cle fibers in the EOM of strabismic patients are limited to the muscle body and have not allowed a conclusive interpretation to be drawn [12-14.16], since most of the EOM fea tures present in strabismic patients have also been found in normal subjects.…”

Section: Introductionmentioning

confidence: 99%

Extraocular Muscles in Congenital Strabismus: Muscle Fiber and Nerve Ending Ultrastructure according to Different Regions

et al. 1992

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The ultrastructure of the extraocular muscles of patients affected by congenital strabismus is not completely known, and the structures responsible of the pathogenesis of this condition are still to be determined. Specimens obtained from patients suffering from congenital strabismus were studied and compared with specimens obtained from patients enucleated for various pathologies and not affected by any disorder in the oculomotor system. The scleral myotendinous junction, where the occurrence of an altered proprioceptive innervation was already reported, was examined, and findings obtained were compared with those observed in the muscle body (venter), where motor innervation is prominent and usually described as normal. Only a small number of damaged muscle fibers was found everywhere. The damage consisted in alterations of both contractile structures and mitochondria and resulted in severer lesions in the scleral myotendinous junction rather than in the muscle body. The normal muscle fibers were innervated by motor nerve endings with normal features and by few altered proprioceptors. The less damaged muscle fibers were innervated by normal motor nerve endings and severely damaged proprioceptors. The most severely damaged muscle fibers did not receive any type of innervation. These data seem to imply that the most important functional alteration in strabismus regards the scleral myotendinous junction. It is the authors’ opinion that these findings might have a clinical importance in choosing the treatment to be pursued in patients with a squint.

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Section: Introductionmentioning

confidence: 99%

Extraocular Muscles in Congenital Strabismus: Muscle Fiber and Nerve Ending Ultrastructure according to Different Regions

et al. 1992

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“…8 Patients with ocular motility disorders manifest pathological changes in their extraocular muscles including atrophy, decreased volume and number of the muscle fiber, abnormal alignment, and collagen proliferation. [13][14][15] Ultrastructural changes observed under transmission electron microscopy include sarcomere destruction, unclear M and Z lines, abnormal accumulation of Figure 3 Western blots of myosin and actin. The adolescent group with intermittent exotropia showed significantly higher levels of myosin and actin in the medial recti than the adult group (*Po0.05).…”

Section: Discussionmentioning

confidence: 99%

Ultrastructure of medial rectus muscles in patients with intermittent exotropia

Yao

Wang

Ren

et al. 2015

Eye

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Purpose To study the ultrastructure of the medial rectus in patients with intermittent exotropia at different ages. Patients and methods The medial recti were harvested surgically from 20 patients with intermittent exotropia. Patients were divided into adolescent (ageo18 years, n = 10) and adult groups (age 418 years, n = 10). The normal control group included five patients without strabismus and undergoing eye enucleation. Hematoxylin and eosin staining and transmission electron microscopy were used to visualize the medial recti. Western blot was used to determine the levels of myosin and actin. Results Varying fiber thickness, atrophy, and misalignment of the medial recti were visualized under optical microscope in patients with exotropia. Electron microscopy revealed sarcomere destruction, myofilament disintegration, unclear dark and light bands, collagen proliferation, and fibrosis. The adolescent group manifested significantly higher levels of myosin and actin than the adult group (Po0.05). Conclusion Younger patients with intermittent exotropia show stronger contraction of the medial recti compared with older patients. Our findings suggest that childhood was the appropriate time for surgery as the benefit of the intervention was better than in adulthood.

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“…The lateral rectus muscle fibers showed normal ultrastructural fea tures [4][5][6], Degenerative changes of differ ent intensity were evident. Generally, the changes were similar to those found in the medial rectus muscle.…”

Section: Electron Microscopy Lateral Rectus Musclementioning

confidence: 99%

“…Most muscle fibers showed normal characteristics of human ex traocular muscles [4][5][6]. The fiber size var ied from 10 to 22 pm.…”

Section: Electron Microscopy Lateral Rectus Musclementioning

confidence: 99%

End-Stage Fibrosis of the Lateral Rectus Muscle in Myopia with Esotropia

Meyer

Ludatscher²,

Lichtig³

et al. 1990

Ophthalmic Res

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The fibrotic lateral rectus muscle and the medial rectus muscle of 4 patients with esotropia and myopia who underwent surgical correction were studied ultrastructurally. All patients revealed underactivity of the lateral rectus muscle. In 3 patients the underactive lateral rectus was completely fibrotic; in 1 patient there was 80% fibrosis, and the rest of the muscle showed different stages of degeneration. The fibrotic lateral recti were composed of collagen fibrils and remnants of degenerated organelles. The collagen fibrils of the lateral recti were of different sizes, and the mean diameter varied from 65 to 92 nm. On the other hand, the interstitial collagen fibrils of nonfibrotic medial rectus muscles of these patients and also of control muscles showed less variation in size, and the mean diameter was smaller as compared with the fibrotic lateral rectus. It is suggested that the collagen fibrils that compose the fibrotic lateral rectus muscle probably develop under conditions which differ from the normal development of collagen fibrils.

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Ultrastructural Studies of Extraocular Muscles in Ocular Motility Disorders

Cited by 10 publications

References 17 publications

Extraocular Muscles in Congenital Strabismus: Muscle Fiber and Nerve Ending Ultrastructure according to Different Regions

Extraocular Muscles in Congenital Strabismus: Muscle Fiber and Nerve Ending Ultrastructure according to Different Regions

Ultrastructure of medial rectus muscles in patients with intermittent exotropia

End-Stage Fibrosis of the Lateral Rectus Muscle in Myopia with Esotropia

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