Ophthalmic presentation of giant cell arteritis in African-Americans.

PurposeTo determine the differences in the presentation of ophthalmic giant cell arteritis between African-Americans and Caucasians.MethodsThis was a multicenter retrospective case series comparing African-American patients with ophthalmic GCA to a previously published Caucasian cohort. Neuro-ophthalmic centers across the United States were contacted to provide data on African-American patients with biopsy-proven ophthalmic giant cell arteritis. The differences between African-American and Caucasian patients with respect to multiple variables, including age, sex, systemic and ophthalmic signs and symptoms, ocular ischemic lesions, and laboratory results were studied.ResultsThe Caucasian cohort was slightly older (mean=76.1 years) than the African-American cohort (mean=72.6 years, P=0.03), and there was no difference in sex distribution between the two cohorts. Headache, neck pain, and anemia were more frequent, while jaw claudication was less frequent in African-Americans (P<0.01, <0.001, 0.02, and 0.03 respectively). Acute vision loss was the most common presentation of giant cell arteritis in both groups, though it was less common in African-Americans (78 vs 98% of Caucasians, P<0.001). Eye pain was more common in African-Americans (28 vs 8% of Caucasians, P<0.01).ConclusionsThe presenting features of ophthalmic giant cell arteritis in African-Americans and Caucasians are not markedly different, although a few significant differences exist, including higher rates of headache, neck pain, anemia, and eye pain, and lower rates of jaw claudication and acute vision loss in African-Americans. Persons presenting with suspicious signs and symptoms should undergo evaluation for giant cell arteritis regardless of race.

Delayed visual loss due to trauma of the internal carotid artery.

The group of six patients in this study experienced delayed visual loss following head trauma. Visual loss occurred from 1 day to 13 years after the initial injury. All patients suffered indirect trauma to the internal carotid artery resulting in formation of either an aneurysm or pseudoaneurysm or a carotid-cavernous fistula. Review of the radiologic and clinical findings was performed in six patients. The diagnosis was established by computed tomography, magnetic resonance imaging, and angiography. All patients had follow-up clinical evaluation and imaging studies. Treatment by neurosurgical or interventional neuroradiologic procedures resulted in significant visual improvement in five patients. Different pathophysiologic mechanisms could be correlated with the delayed visual loss produced by the two types of lesions. The pathologic changes associated with the aneurysms/pseudoaneurysms included direct compression of optic nerves and/or chiasm and intracranial hematoma. A carotid-cavernous fistula caused delayed visual loss by either hematoma at the orbital apex or compression of the chiasm and/or optic nerves by saccular dilatation of the cavernous sinus. The delayed onset of decreased vision following head trauma should alert the physician to the possibility of a traumatic aneurysm/pseudoaneurysm or a carotid-cavernous fistula. Different neuro-ophthalmologic symptoms can usually be correlated with the pathologic changes demonstrated by neuroimaging procedures.

Topography of scalp potentials preceding self-initiated saccades.

We studied 3 scalp potentials recorded prior to saccades in relation to visual targets (the presaccadic negativity [PSN], presaccadic positivity [PSP], and spike potential [SP]) in normal subjects performing self-initiated saccades in darkness. There was a prominent PSN beginning at -800 msec, maximal at the vertex. This finding is consistent with activation of the supplementary eye field in the anterior mesial frontal cortex, a concept which correlates with cortical neuron recordings in monkeys and cerebral blood flow studies in humans. A widespread PSP, with greatest amplitude over the posterior scalp, suggests parieto-occipital participation even in the absence of visual targets. The sharp character of SP with focal lateralized frontal negativity, its "mirror image" scalp distribution when comparing leftward to rightward saccades, and its timing near the onset of saccades support an origin near the orbit, in either ocular motor nerves or muscles.

Isolated trochlear nerve palsy in patients with multiple sclerosis.

The authors describe five patients with trochlear nerve palsy and MS to characterize this rare association. In two patients, trochlear nerve palsy was the initial clinical manifestation of MS. In the other three patients, this sign occurred after previous neurologic events. MRI did not identify a lesion of the fourth nerve nucleus or fascicle. Ophthalmoplegia resolved within 2 months in four of the five patients. A reason this association is rare is that the fascicular course of the trochlear nerve is exposed to little myelin.

Isolated sixth-nerve palsies in younger adults.

Acquired sixth-nerve palsies are relatively rare in younger adults. We reexamined 49 patients, aged from 15 to 50 years, with isolated sixth-nerve palsies who were seen between 1972 and 1982 at the Wills Eye Hospital in Philadelphia. In this group, the following etiologies were encountered: vasculopathy (14 patients [29%]), tumors (eight patients [16%]), multiple sclerosis (six patients [12%]), presumed inflammation (four patients [8%]), trauma (three patients [6%]), postlumbar puncture (two patients [4%]), and orbital amyloidosis (one patient [2%]). Eleven patients (22%) had no determined cause of their sixth-nerve palsy. The implications for the clinical management of isolated sixth-nerve palsies in younger adults are discussed.

Visual loss after coronary artery bypass surgery.

A 70-year-old man underwent coronary artery bypass graft complicated postoperatively by visual loss. The diagnosis was nonarteritic anterior ischemic optic neuropathy. Possible predisposing factors in this patient were hypotension, anemia, a "disk at risk," and internal carotid artery stenosis. In the postoperative setting, the erythrocyte sedimentation rate may be elevated, as it was in this case and does not by itself suggest a diagnosis of giant cell arteritis.

Unilateral disk edema in a young woman.

A patient with elevated intracranial pressure from aqueductal stenosis presented with unilateral disk edema, enlarged blind spot and a vague visual disturbance. The importance of considering elevated intracranial pressure in some cases without bilateral papilledema is emphasized.

Physiologic functional imaging in "functional" visual loss.

Neuroimaging with nuclear medicine techniques permits assessment of brain function by measurement of metabolism or blood flow. Such studies complement the anatomic information derived from computed tomography (CT) or magnetic resonance imaging (MRI). We describe two patients with occipital lesions who were initially diagnosed with functional visual loss. Neither CT scan nor MRI adequately demonstrated the source of visual dysfunction; however, single proton emission tomography (SPECT) scanning in a patient with carbon monoxide poisoning and positron emission tomography (PET) scanning in a patient with post-hypoxic delayed encephalopathy were helpful in confirming the organic substrate of their visual impairment. Functional imaging techniques such as SPECT and PET should be considered in patients with suspected cortical visual loss and normal CT or MR scans.

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.

Use of a portable head mounted perimetry system to assess bedside visual fields.

AIM: This study was designed to test the ability of a portable computer driven, head mounted visual field testing system to perform automated perimetry on patients at their bedside and to compare these results with the "gold standard" for bedside examinations, confrontation visual fields. METHODS: The Kasha visual field system is a portable automated perimeter which utilises a virtual reality headset. 37 neurosurgery patients were examined at their bedside with a central 24 degree suprathreshold testing strategy after confrontation visual field testing. The patterns of visual field defects were categorised and compared with the results of confrontation testing. RESULTS: A total of 42 field examinations were completed on 37 patients, and the average testing time for both eyes was 4.8 minutes with the perimetry system. Each of the 11 fields (100%) classified with defects on confrontation testing was similarly categorised on head mounted perimetry. 26 out of 31 (84%) visual fields were normal on both confrontation and perimetry testing, while five out of the 31 fields (16%) which were full on confrontation had visual field defects identified by head mounted perimetry. CONCLUSION: The head mounted, automated perimetry system proved easily portable and convenient for examining neurosurgical patients at their bedside in the perioperative period. The device demonstrated equal sensitivity to confrontation visual field testing methods in detecting field defects and offers the advantage of standardised, quantifiable testing with graphic results for follow up examinations.

Radiation-induced optic neuropathy: a magnetic resonance imaging study.

Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.

Nystagmus.

Patients who present with nystagmus may have visual loss, a benign peripheral vestibular abnormality, or an important central nervous system disorder. The clinical history, features of nystagmus on examination, and accompanying symptoms and findings often help to localize the lesion. These features also determine the appropriate evaluation and treatment of the underlying disorder. Additionally, if there is oscillopsia or blurred vision, treatment of the nystagmus itself may be warranted. Possible treatments include medication, optical manipulations, and surgery.

A neuro-ophthalmologist's perspective on neuroradiology.

The practice of neuro-ophthalmology includes evaluating patients for visual signs and symptoms for neurological causes. Responsible lesions are often small and in places not well imaged on routinely ordered brain imaging studies. To achieve a proper diagnosis, the clinician must have a close working relationship with the radiologist to choose the appropriate imaging study and to correctly focus the study based on clinical findings.

Dural carotid-cavernous sinus vascular malformation with facial nerve paresis.

Facial nerve paresis is rarely seen in dural cavernous sinus arteriovenous malformations or carotid-cavernous sinus fistulae. A patient with an otherwise typical presentation of a spontaneous carotid-cavernous sinus malformation was found to have ipsilateral infranuclear facial nerve paresis. Angiography revealed a dural arteriovenous malformation with early petrosal sinus filling. Possible mechanisms for the paresis include compression of the facial nerve by increased venous pressure and "stealing" of the arterial supply by the malformation.

Abnormal function of the parvocellular visual system in anisometropic amblyopia.

PURPOSE: To study the function of the parvocellular (P) and the magnocellular (M) visual systems with steady-state visual evoked potentials (VEPs) in anisometropic amblyopes. METHODS: A matrix of isolated checks was superimposed on a steady background with different check sizes and temporal frequencies to form specific stimuli to preferentially activate the P or the M visual system. The amplitude of the VEP fundamental frequency was analyzed at the electrode Oz of 5 anisometropic amblyopes and 22 normal subjects. The normal subjects were tested at two visual acuity (VA) levels, 20/20 and 20/40, modified by lenses, to match with the VA levels of the fellow eyes and the amblyopic eyes of the amblyopes, respectively. RESULTS: No significant amplitude difference was found between the dominant eyes and nondominant eyes of the normal subjects for either P or M stimuli at both 20/20 and 20/40 VA levels (P>.05). No significant amplitude difference was found between the fellow eyes of the amblyopes and the dominant eyes of normals for either P or M stimuli at 20/20 VA level (P>.05). A significant amplitude difference was found between the amblyopic eyes and the nondominant eyes of the normals for P stimuli (P<.05) but not for M stimuli (P>.05) at 20/40 VA level. CONCLUSIONS: The amplitude of the VEP fundamental frequency was selectively reduced for P stimuli in anisometropic amblyopic eyes. This clinical electrophysiologic finding confirms that only the function of the P visual system is abnormal in anisometropic amblyopic eyes.

The peak latency of orbital presaccadic spike potential with horizontal eye movements.

PURPOSE: To investigate the peak latency of the orbital presaccadic spike potential (SP) with horizontal eye movement in normals. METHODS: Orbital SP was recorded in 28 normal subjects from 8 electrodes around the eyes with Pz as the reference while performing 5 degrees, 10 degrees, 20 degrees, 30 degrees and 40 degrees horizontal saccades to visual targets. SP peak latency was measured from SP onset to SP peak on averaged data aligned on SP peak. RESULTS: Significant main effects on SP peak latency are found for saccade size (P < 0.01), saccade direction (P < 0.01) and electrode site (P < 0.05). No significant main effect on SP peak latency is found for eye (P > 0.05). SP peak latency increases with increasing saccade size from 5 degrees to 40 degrees. SP peak latency is longer with saccades back to center than away from center, and with abducting saccades than with adducting saccades. SP peak latency differs at the electrode sites with an order from shorter to longer as follows: inner canthus (IC); inferior orbit (IO); outer canthus (OC); superior orbit (SO). CONCLUSIONS: The effects on the peak latency of orbital SP can be explained by the saccade dynamic property, volume conduction as well as physiologic and anatomic factors of the eyes and orbits. The peak latency of orbital SP can be used to reflect the temporal characteristics of ocular motor units controlling saccadic eye movement.