Dysthyroid optic neuropathy without extraocular muscle involvement.

We present three atypical cases of dysthyroid optic neuropathy. The unique feature was progressive visual field loss with normal-sized or minimally enlarged extraocular muscles. Other atypical findings included optic nerves that appeared to be linearly on stretch with only moderate proptosis, good ocular motility, and only mildly reduced central visual acuity and color vision despite severe field loss. These cases responded rapidly to decompressive surgery after failing high-dose corticosteroid therapy. While marked enlargement of the extraocular muscles with apical optic nerve compression has been documented to cause dysthyroid optic neuropathy, another etiology such as short optic nerves on stretch appears to be at work in these atypical cases. Although extraocular muscle enlargement is the most important diagnostic feature and indicator of the severity of Graves' ophthalmology, our atypical cases demonstrate that this sign alone is an inadequate basis for diagnosis and visual prognosis.

Hemifacial spasm. Results of unilateral myectomy.

Hemifacial spasm (HFS) is a disorder characterized by unilateral involuntary spasm of the muscles innervated by the facial nerve (cranial nerve VII). The etiology is often a redundant or ectatic artery in the cerebellopontine angle that compresses the facial nerve. Neurosurgical decompression with implantation of a sponge between the ectatic artery and the facial nerve produces good results, but has a high complication rate and a poor patient acceptance rate. Various modes of peripheral neurectomy have also been advocated, but the recurrence rate is high and the preexisting functional and cosmetic eyelid deformities are exacerbated. The results of unilateral periorbital myectomy in 21 HFS patients are presented. Follow-up ranging from 1 to 7 years was available on 16 patients. Excellent or good results were obtained in 94% of these cases, and postoperative complications were minor. Transient lymphedema and forehead anesthesia are the most common complications. An unforseen benefit of periorbital myectomy surgery is the improvement or relief of lower facial contractions that occurred in 75% of patients. The authors believe the myectomy procedure is a safe, effective, predictable therapy for those HFS patients unwilling to risk a neurosurgical operation, and allows simultaneous reconstruction of associated eyelid and eyebrow deformities.

Congenital orbital teratoma: a review and report of two cases.

Congenital orbital teratomas are rare tumors derived from more than one germinal cell layer. These tumors may arise within the orbit, or may originate intracranially and extend into the orbit. Recent advances in ultrasonography have made in utero diagnosis possible. We present the case reports of a primary orbital teratoma and an intracranial teratoma with secondary orbital involvement. The clinical features, histopathologic findings, treatment, and pathogenesis of orbital teratomas are discussed.

Orbital hydatid cyst.

A six-year-old Bantu child presented with a mass in the right orbital region, proptosis, and moderate pallor of the optic disk. Orbital exploration revealed an unsuspected hydatid cyst. The characteristic histopathologic features of the organism Echinococcus granulosus are emphasized.