discussion-presentation04

• Individuals younger than 40 yr of age are considerably more likely to exhibit orbital fat expansion in the absence of muscle enlargement, whereas patients over 70 yr are more prone to severe, fusiform muscle enlargement without significant changes in orbital adipose tissue volume.
• Proptosis, stems from this increase in orbital tissue volume within the unyielding confines of the bony orbit. Extraocular muscle dysfunction is caused, early in the disease, by swelling of the muscle bodies.
• In later stages the extraocular muscles may become fibrotic and atrophic as a result of chronic inflammation and compression of the muscle fibers.
• Chemosis and periorbital edema appear to be caused primarily by decreased venous and lymphatic drainage from the orbit secondary to compression of these channels.