Enophthalmus

ENOPHTHALMUS, the recession of the eyeball into the orbital cavity, is observed in diseases of the nervous system, as well as in local diseases of the orbit. Among the divisions of the nervous system, enophthalmus is caused mainly by diseases of the sympathetic system: primarily, lesions of the spinal cord in the region of D_I–C_VIII, where the ciliospinal center of the sympathetic system and the anterior roots of these segments are located; then, lesions of the cervical section of the sympathetic trunk and the superior cervical ganglion due to some process (aneurysm of the carotid artery, tumors, enlarged packet of lymph nodes, etc.); various processes at the base of the brain can also involve the sympathetic fibers extending from the carotid plexus, and diseases of the Gasserian ganglion and the upper branch of the trigeminal nerve can involve the sympathetic fibers heading toward the orbital region, along with the branches of the first division of the trigeminal nerve. Furthermore, various processes in the orbit itself, leading to the formation of scars (intraorbital hemorrhages), and severe general diseases accompanied by emaciation can cause enophthalmus; finally, enophthalmus can be congenital. The pathogenesis of enophthalmus in diseases of the sympathetic system is explained as follows: the eye is maintained in the orbital cavity in a normal position by Müller's muscle, which lies in the posterior angle of the orbit and receives innervation from the sympathetic system, and therefore, a lesion of this system is reflected in the muscle tone; it weakens, and the eye, losing its support, recedes; this fact has been verified experimentally in animals—removal of the superior cervical ganglion caused enophthalmus. Some authors deny this significance of Müller's muscle but do not offer their own explanations. Clinically, a more or less clearly expressed recession of the eyeball into the orbital cavity is observed, for the most part unilateral (it is bilateral only in wasting diseases), along with narrowing of the palpebral fissure and constriction of the pupil with its normal reaction (see figure); very often, vasomotor and secretory disorders of the corresponding half of the face are observed simultaneously, which is explained by the proximity of the centers. Diagnosis comes down to the localization of the process, in which accompanying symptoms can help. Prognosis and therapy depend on the etiological factor. Bibliography—see bibliography for the article Exophthalmus.