Electron microscopic study of Duane's syndrome,endocrine ophthalmopathy and other myopathies with strabismus

The lateral and the medial rectus muscles from children with special forms of strabismus are described ultrastructurally. In Duane's retraction syndrome, the lateral rectus muscle was composed of mature and immature collagen fibrils and no nerve structures could be identified in the whole bulk of tissue. the medial rectus was partly fibrotic and partly composed of muscle fibers showing various stages of degeneration. Nerve axons were seen adiacent to the muscle cells. In endocrine ophthalmopathy and rod myopathy, the muscle fibers showed myofibrillar degeneration and abnormalities of the Z-band and also an increase in the amount of the interstitial collagen tissue. It is concluded that the absence of nerve structures in the area of the totally fibrotic lateral rectus muscle supports the view that Duane's syndrome is related to a neurogenic abnormality.