Enlargement of extraocular muscles The stimulated fibroblasts produce glycosaminoglycans (GAGs)which cause the muscle to swell Muscle size may increase by up Swollen muscles to 8 times The swollen muscles occupy orbital space and can compress Compression the optic nerve ofoptic nerve These swollen muscles can at apex oforbit cause a forward propulsion of the globe (proptosis)so that the eyelids do not cover well and Swollen muscle(medialrectus) eyes dry out,causing exposure keratopathyEnlargement of extraocular muscles • The stimulated fibroblasts produce glycosaminoglycans (GAGs) which cause the muscle to swell • Muscle size may increase by up to 8 times • The swollen muscles occupy orbital space and can compress the optic nerve • These swollen muscles can cause a forward propulsion of the globe (proptosis) so that the eyelids do not cover well and eyes dry out, causing exposure keratopathy Swollen muscles Compression of optic nerve at apex of orbit Swollen muscle (medial rectus)