Latif M. Hamed

Strabismus Presenting after Cataract Surgery

Strabismus presenting after cataract surgery is etiologically related to a heterogenous group of disorders. Clinical data from 63 patients so affected revealed four broad etiologic categories: 1) pre-existing disorders that preceded the cataract surgery, but were rendered asymptomatic by the occluding cataract (e.g., thyroid eye disease, cranial nerve palsy, myasthenia); 2) disorders precipitated by prolonged occlusion by a cataract (e.g., sensory deviations, decompensation of heterophorias, and central disruption of binocular vision); 3) disorders resulting from surgical trauma to extraocular muscles and orbital soft tissues. Traumatic injury to the inferior rectus muscle secondary to retrobulbar anesthesia injection, a specific subset, is postulated to result from a Volkmanns type ischemic contracture, a well-known osseofascial compartment syndrome occurring in peripheral skeletal muscles. 4) Disorders related to resulting aphakia/pseudophakia and associated optical aberrations (e.g.; anisophoria, ocular dominance reversal, and color/brightness disparity). The diagnostic and therapeutic implications of these findings are discussed.

Central Nervous System Structure and Function in Sturge-Weber Syndrome: Evidence of Neurologic and Radiologic Progression

Sturge-Weber syndrome is characterized by the presence of a port-wine nevus, epilepsy, stroke-like episodes, headache, and developmental delay. We studied 20 cases to test the hypothesis that decreased cerebral blood flow alters neurologic function by affecting cellular glucose metabolism. Group A consisted of 10 patients with a mean age of 1.75 years and early seizure onset (6.8 months), whereas group B was composed of older patients (mean age, 15.3 years) with later onset of seizures (3.7 years). Neurologic disease was more severe in group A, but group B had more widespread structural brain defects — shown on computed tomographic scans and magnetic resonance imaging — and metabolic brain defects — shown on hexamethylpropyleneamine oxime and [18F] fluorodeoxyglucose single photon emission computed tomographic scans. Six group A cases had hypoperfusion at baseline and five of nine had worsening of perfusion and glucose metabolism 1 year later. A total of 119 stroke-like episodes occurred in six group A cases and eight group B cases; there were 65% fewer strokes in children treated with aspirin. The data suggest that progressive hypoperfusion and glucose hypometabolism are associated with neurologic deterioration in Sturge-Weber syndrome. Longitudinal studies are needed to better define the natural history of disease and to evaluate the safety and efficacy of aspirin therapy. (J Child Neurol 1998;13:606-618).

Inferior Rectus Muscle Contracture Syndrome after Retrobulbar Anesthesia

Ipsilateral hypotropia with restricted elevation is an increasingly recognized strabismic entity resulting from injury to the inferior rectus muscle after local retrobulbar anesthesia. Eight patients with this disorder are described. Computed tomography of the orbit in three patients demonstrated isolated segmental enlargement of the retrobulbar portion of the inferior rectus muscle; the findings of magnetic resonance imaging in one patient was most compatible with fibrosis. Four patients underwent strabismus surgery consisting of adjustable recession of the affected inferior rectus muscle; all recovered single binocular vision in the functional fields of gaze postoperatively. Surgical exploration of the ipsilateral inferior rectus muscle demonstrated normal anatomy in the peribulbar portion of the muscle.

The spectrum of optic nerve disease in human immunodeficiency virus infection

We studied four patients with HIV-associated optic neuropathies. One had syphilitic optic perineuritis, which responded promptly and completely to penicillin therapy. The second had cytomegalovirus papillitis and visual acuity subsequently deteriorated to no light perception. The third showed varicella zoster optic neuritis, which improved after intravenous acyclovir treatment. The fourth patient developed cryptococcal retrobulbar neuritis and died shortly thereafter. Optic neuropathy was among the initial symptoms of HIV infection in two of the four cases.

Topical Review Article: Brainstem Glioma: I. Pathology, Clinical Features, and Therapy

Gliomas that arise in the brain stem have been associated with a poor prognosis. Diagnostic neuroimaging readily identifies the tumor as it extends between normal brainstem structures. Histologic sampling of tumor with stereotactic methods is notoriously unreliable in establishing a definitive prognosis. Clinical trials that incorporate high-dose chemotherapy, autologous bone marrow rescue, and irradiation hold promise of better tumor control by overcoming the inaccessibility of the central nervous system to standard doses of chemotherapy. We review the pathology, clinical features, neuroimaging features, and current therapeutic concepts relative to brainstem glioma. The pediatric neurologist has a pivotal role in identifying and monitoring children with this malignancy. (J Child Neurol 1993;8:112-128).

Giant Cell Arteritis in the Ocular Ischemic Syndrome

Oculomotor nerve paresis, ocular hypotony, anterior segment ischemia, and the ocular ischemic syndrome are uncommon manifestations of giant cell arteritis. Four patients with these findings had giant cell arteritis documented by temporal artery biopsy. Cerebral angiography or ultrasonography, or both, performed in three patients, excluded hemodynamically significant stenosis of the internal carotid artery as the cause of ocular ischemia and cerebral aneurysms as the cause of oculomotor nerve paresis. Corticosteroid treatment, administered to three patients, resulted in resolution of the oculomotor deficits and the clinical signs of ocular ischemia, although the visual acuity in one patient improved from 20/400 to 20/60. Giant cell arteritis should be considered in the differential diagnosis of the ocular ischemic syndrome.

Optic Neuropathy in Uremia

We examined three patients who developed optic neuropathies while undergoing chronic hemodialysis. One patient developed severe bilateral deterioration of vision, but recovered totally four weeks after discontinuing deferoxamine chelation therapy. Another patient had bilateral visual loss associated with chronic papilledema of idiopathic increased intracranial pressure. A third showed atypically severe consecutive anterior ischemic optic neuropathy. The latter two patients showed little improvement with high-dose intravenous methylprednisolone therapy combined with more vigorous hemodialysis. These cases, in addition to those previously described, underscore the heterogeneity of optic nerve disease in patients with uremia.

Treatment of acute comitant esotropia in Chiari I malformation

PURPOSE To explore the appropriate treatment of acute comitant esotropia in patients with Chiari I malformation. DESIGN Interventional case reports and literature review. PARTICIPANTS Two patients with Chiari I malformation presenting with acute comitant esotropia are described. INTERVENTION Strabismus surgery, then neurosurgical decompression of the Chiari I malformation was performed. MAIN OUTCOME MEASURE Both patients were evaluated for resolution of esotropia and other ocular motility problems. RESULTS After initially successful strabismus surgery, both patients developed recurrent esotropia with diplopia, which resolved on suboccipital decompression. CONCLUSION Comitant esotropia may recur and other eye movement disorders may develop after initially successful strabismus surgery in patients with Chiari I malformation. The data suggest that the appropriate sequence of treatment should first be suboccipital decompression, then strabismus surgery if spontaneous realignment does not occur, but further studies are needed to confirm this impression.

Associated Neurologic and Ophthalmologic Findings in Congenital Oculomotor Nerve Palsy

Unlike acquired oculomotor nerve palsy in childhood, the congenital form is usually considered to be an isolated disorder, not associated with other neurologic or systemic disease. In a series of 14 patients with this diagnosis, 10 had associated neurologic disorders. Clinical-neuroradiologic correlation identified the brainstem as the site of the lesion in some patients. The ipsilateral pupil was involved in 12 patients and was miotic with a trace or no reaction to light on the side of the palsy in 8 of the 12 patients. In two of these eight patients, the pupil was documented to be dilated and fixed in early infancy and subsequently became miotic at several months of age, concurrent with emergence of other signs of aberrant reinnervation. Pupillary miosis as a result of aberrant reinnervation appears to be much more frequent after congenital than acquired pupillary-involving oculomotor palsy. Four patients showed better visual acuity in the paretic eye, an unexpected finding. The paretic eye appeared to have a fixational advantage if the patient had nystagmus, presumably due to asymmetric dampening of the nystagmus. Significant anisometropia and astigmatic errors in the paretic eye were present in essentially all patients.

Thyroid eye disease presenting after cataract surgery.

Strabismus presenting after cataract surgery has been attributed to a variety of disorders, some of which are unrelated to the surgery. When thorough ophthalmologic and neurologic examinations fail to elucidate a definitive etiology, the motility disturbance is often ascribed to operative trauma to the orbital soft tissues. In a series of 58 patients with strabismus presenting after cataract surgery, eight (14%) were found to have previously unsuspected thyroid eye disease. Three of the eight patients had past histories of systemic dysthyroidism, but none reported diplopia prior to cataract extraction. Three of the remaining five patients showed normal thyroid function tests. Absence of diplopia prior to cataract extraction in these patients may be due to: 1) poor vision precluding diplopia until surgical restoration of sight; 2) intraoperative aggravation of the inflammatory process in otherwise subclinical thyroid eye disease; or 3) onset of clinical thyroid eye disease that was temporally associated with cataract surgery by chance. Thyroid eye disease should be included in the differential diagnosis of all patients presenting with binocular diplopia following cataract surgery. Suitable neuroimaging studies may be needed to confirm the diagnosis.