Chronic ataxic neuropathy mimicking dorsal midbrain syndrome.

We describe the clinical course, with special attention to the disturbance of eye movements, of a 29-year-old man with chronic ataxic neuropathy with ophthalmoplegia, IgM paraprotein, cold agglutinins and anti-GD1b disialosyl antibodies (CANOMAD). Using the magnetic search coil technique, we documented convergence during upward saccades and other features suggestive of dorsal midbrain syndrome. Thus, in common with Miller Fisher syndrome, CANOMAD may present with clinical findings implicating involvement of the central nervous system, which contains ganglioside antigens to anti-GD1b antibodies.

Neuro-ophthalmologic complications of cardiac catheterization.

We examined ten patients who, from 1981 to 1986, sustained neuro-ophthalmologic events during cardiac catheterization. Eight patients, most of whom recovered, were believed to have sustained embolic phenomena. Two patients experienced a typical migraine during the catheterization and likewise did well. We conclude that the likelihood of sustaining a neuro-ophthalmic complication during cardiac catheterization is low and that the prognosis after having sustained such a complication is generally favorable. Evidence suggests that artery-to-artery emboli is the dominant pathogenic factor.

The characteristics and mechanisms of visual disturbance associated with anticonvulsant therapy.

Eight epileptic patients receiving anticonvulsants had recurrent visual disturbances in the form of diplopia and oscillopsia in the horizontal or vertical planes. The symptoms could be ascribed to impaired vergence mechanisms, vertical nystagmus, or abnormalities of the vestibulo-ocular reflex. Other eye movements, such as pursuit and gaze-holding, were also affected, but did not lead to complaints. Episodes of visual disturbance were often preceded by prodromes of ocular or systemic discomfort, after which oscillopsia or diplopia evolve rapidly. The symptomatology was stereotyped but unique for each patient and may reflect idiosyncratic susceptibility to the ocular motor side effects of anticonvulsants. Six of the 8 patients were taking carbamazepine and phenytoin in combination, which have similar effects on the ocular motor system.

Preservation of voluntary saccades after intracarotid injection of barbiturate.

We studied voluntary saccades in 44 patients undergoing Wada testing before surgery for intractable epilepsy. After intracarotid injection of barbiturate, and while they were hemiplegic, patients could still make voluntary saccades toward or away from the side of injection. Sustained ipsiversive deviation of gaze was not noted. Saccades made away from the side of injection were slower than ipsilateral saccades in only 3 of 10 tests. These data support the hypothesis of parallel, independent pathways from the frontal eye fields and from the superior colliculi to the brainstem reticular nuclei that generate saccades.

Effect of monocular visual loss upon stability of gaze.

Using the eye-coil/magnetic field method, we measured horizontal and vertical movements of both eyes in four patients with monocular loss of vision while they attempted steady, binocular fixation of a visual target. We also measured gaze stability in two normal subjects while they fixed upon a target monocularly, and in one patient with congenital, bilateral blindness. In the patients with monocular visual loss, gaze instability was greater in the blind eye, both vertically and horizontally, compared either with their seeing eye or with nonviewing eyes of control subjects. Gaze instability due to monocular blindness resulted from: (1) low-frequency, low-amplitude, bidirectional drifts that were more prominent vertically; and (2) unidirectional drifts, with nystagmus, that were more prominent in the horizontal plane. Gaze-evoked nystagmus, however, was not a feature of monocular blindness. Thus, the gaze instability of monocular blindness may reflect disruption of: (1) a monocular visual stabilization system; (2) fusional vergence mechanisms; or (3) both. In contrast, bilateral congenital blindness led to nystagmus with horizontal and vertical components and a wandering null point, indicative of an abnormal neural integrator.

Superior oblique myokymia. Quantitative characteristics of the eye movements in three patients.

Using the magnetic search coil technique, we measured horizontal, vertical, and torsional rotations of both eyes of two patients with idiopathic superior oblique myokymia, and of the affected eye in a third patient. Superior oblique myokymia was strictly monocular and consisted of an initial intorsion and depression of the affected eye and subsequent oscillations with torsional and vertical components. The peak-to-peak torsional and vertical amplitudes of the oscillations were less than 1 degree, but peak velocities frequently exceeded 4 degrees/sec in both planes. Fourier analysis indicated two features: (1) a broad range of frequencies up to about 50 Hz, indicating irregular oscillations; and (2) a superimposed larger-amplitude oscillation in the range from 1.5 to 6 Hz. Taken with electromyographic data from other studies, these results indicate that superior oblique myokymia reflects spontaneous discharge of trochlear motor neurons that have undergone regenerative changes.

Magnetic resonance images in a case of "divergence paralysis".

The clinical syndrome of divergence paralysis has been described since the mid 19th century. Speculation still surrounds the possible existence of an anatomical center for divergence function. Our report explores this possibility and describes the magnetic resonance images of a patient with a unilateral 6th nerve palsy who later developed the clinical picture of divergence paralysis.

Ischemic optic neuropathy associated with retinal embolism.

Ischemic optic neuropathy occurred in three patients (a 55-year-old man and two women, 64 and 68 years old). Visual loss followed coronary bypass surgery in two patients who also had diffuse atherosclerotic disease. Retinal emboli were present in both eyes of each. The third patient developed ischemic optic neuropathy with evidence of ipsilateral retinal emboli shortly after cardiac catheterization. Her only other risk factor for ischemic optic neuropathy was systemic hypertension. Although highly unusual, ischemic optic neuropathy may be associated with and possibly caused by a shower of emboli to the eye.

A retrospective review of 26 cases of dysthyroid optic neuropathy.

Sixteen patients (14 women and two men) with dysthyroid optic neuropathy (26 involved eyes) were treated with either oral corticosteroids, orbital irradiation, surgical orbital decompression, combined corticosteroids and irradiation, or combined corticosteroids and surgical decompression. Thirteen of 16 eyes responded favorably to corticosteroid therapy but eight of the 13 relapsed upon discontinuation of treatment. Two of four eyes responded to irradiation initially but later relapsed. The response to orbital decompression was almost uniformly beneficial (eight of nine eyes responded) and lasting in all. Combined modes of therapy offered no additional advantage.

Structural factors in the pathogenesis of ischemic optic neuropathy.

Some patients with nonarteritic ischemic optic neuropathy have no signs or symptoms of systemic vascular disease; therefore, nonvascular factors may play a role in the pathogenesis of this syndrome. We observed that the average cup-disk ratio of the unaffected optic disks in a group of patients with ischemic optic neuropathy was significantly (P = .005) smaller than the average ratio in a group of age-matched controls (0.36 +/- 0.19 vs 0.21 +/- 0.16). Fourteen of 30 patients but only two of 29 controls had cup-disk ratios equal to or less than 0.1. Mechanical factors, such as constriction of axons as they traverse the scleral canal, may contribute to the pathogenesis of ischemic optic neuropathy.

Computed tomographic features in optic neuritis.

A computed tomography scan obtained in two patients with monocular visual loss showed diffuse enlargement and enhancement of the intraorbital portion of the involved optic nerve. Although these tomographic features were initially interpreted as an optic nerve glioma by the neuroradiologist, the ensuing clinical course established the diagnosis of optic neuritis.

Unsatisfactory treatment of acquired nystagmus with retrobulbar injection of botulinum toxin.

PURPOSE: We quantified the effects of botulinum toxin injected into the retrobulbar space of patients with acquired nystagmus with prominent vertical or torsional components. METHODS: We measured binocular eye rotations in three planes before and after injection of botulinum toxin (10, 12.5, or 25 units) into the retrobulbar space of one eye of each of three patients, ages 28 to 37 years, with acquired pendular nystagmus. RESULTS: Retrobulbar injection of botulinum toxin abolished or reduced all components of the nystagmus in the treated eye in all three patients for about two to three months. The patient who received 25 units developed complete external ophthalmoplegia and blepharoptosis. The other two patients retained some voluntary movements but developed diplopia. In one patient, visual acuity improved from Jaeger 5 to Jaeger 1. In a second patient, filamentary keratitis developed, and visual acuity declined from Jaeger 2 to Jaeger 7; keratitis was a recurrent problem one year after the botulinum toxin injection. In the third patient with predominantly torsional nystagmus, visual acuity was unchanged at Jaeger 2. No patient was pleased with the results, because of blepharoptosis, diplopia, or discomfort (from keratitis), and none elected to repeat the procedure. CONCLUSIONS: The side effects of botulinum toxin administered by retrobulbar injection limit its therapeutic value in the treatment of acquired nystagmus. Even smaller doses that do not abolish nystagmus may produce troublesome diplopia.

Ophthalmologic aspects of headache.

Pain around the eye can be caused by local ophthalmic disorders or by disease of other structures sharing trigeminal nerve sensory innervation. In general, most ocular causes for pain also cause the eye to be red, thus alerting the examiner to the focality of the problem. However, conditions like eyestrain, intermittent angleclosure glaucoma or neovascular glaucoma, and low-grade intraocular inflammation can be painful and not be associated with obvious redness. Ocular signs and symptoms also occur with numerous other causes of headache. Double vision in association with periocular pain can result from orbital lesions, isolated cranial neuropathies, and cavernous sinus lesions. Pupillary abnormalities like Horner's syndrome may result from a variety of painful conditions, including cluster headache, parasellar neoplasms or aneurysms, internal carotid dissection or occlusion, and Tolosa-Hunt syndrome. Pain with a dilated and unreactive pupil may reflect a benign condition like Adie's syndrome or ophthalmoplegic migraine, or it may herald the presence of a life-threatening posterior communicating artery aneurysm. Headache and transient visual loss can be manifestations of classic migraine, or be symptoms of ocular hypoperfusion from ipsilateral internal carotid occlusion or increased intracranial pressure from pseudotumor cerebri. In a young patient, head pain with a fixed visual deficit may result from optic neuritis, in an older adult, temporal arteritis may be the culprit. Ophthalmologic aspects of headache thus encompass problems that range from simple and benign to complex and formidable.

Retinal artery pressure and cerebral artery perfusion pressure in cerebrovascular occlusive disease.

The objectives of the investigation were to measure the retinal artery pressure (RAP) and cortical artery pressure (CAP) in patients undergoing superficial temporal artery to middle cerebral artery (STA-MCA) bypass, to study the relationship between these pressures, and to evaluate our ability to predict CAP on the basis of RAP. The 44 patients undergoing bypass surgery included 26 with ipsilateral internal carotid artery (ICA) occlusion (Group I), 5 with bilateral ICA occlusion (Group II), 4 with inaccessible ICA stenosis proximal to the ophthalmic artery (OA) (Group III), 2 with ICA stenosis distal to the OA (Group IV), 3 with ICA occlusion distal to the OA (Group V), 2 with MCA stenosis (Group VI), and 2 with MCA occlusion (Group VII). Five patients undergoing craniotomy for an asymptomatic saccular aneurysm were used as controls. Mean RAP (MRAP) was measured by ophthalmodynamometry (ODM) and was expressed as a ratio of the mean systemic arterial blood pressure (i.e., MRAP/MSAP). The mean MRAP/MSAP for combined Groups I, II, and III with ICA occlusion proximal to the OA was significantly lower than both the control group (P = 0.0001) and the combined Groups IV, V, VI, and VII with occlusive lesions distal to the OA (P = 0.0001). Six patients in Groups I and II with venous stasis retinopathy had a mean MRAP/MSAP of 0.18 +/- 0.11. Mean cortical artery pressure (MCAP) was measured by inserting a 26 gauge needle into a small cortical artery and was expressed as the MCAP/MSAP ratio. Mean MCAP/MSAP was less than 0.50 for all groups except Group III.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamic properties of the human vestibulo-ocular reflex during head rotations in roll.

We investigated the dynamic properties of the human vestibulo-ocular reflex (VOR) during roll head rotations in three human subjects using the magnetic search coil technique. In the first of two experiments, we quantify the behavior of the ocular motor plant in the torsional plane. The subject's eye was mechanically displaced into intorsion, extorsion or abduction, and the dynamic course of return of the eye to its resting position was measured. The mean predominant time constants of return were 210 msec from intorsion, 83 msec from extorsion, and 217 msec from abduction, although there was considerable variability of results from different trials and subjects. In the second experiment, we quantify the efficacy of velocity-to-position integration of the vestibular signal. Position-step stimuli were used to test the torsional or horizontal VOR, being applied with subjects heads erect or supine. After a torsional position-step, the eye drifted back to its resting position, but after a horizontal position-step the eye held its new horizontal position. To interpret these responses we used a simple model of the VOR with parameters of the ocular motor plant set to values determined during Exp 1. The time constant of the velocity-to-position neural integrator was smaller (typically 2 sec) in the torsional plane than in the horizontal plane (> 20 sec). No disconjugacy of torsional eye movements was observed. Thus, the dynamic properties of the VOR in roll differ significantly from those of the VOR in yaw, reflecting different visual demands placed on this reflex in these two planes.

Autoimmune reactivity in Cogan's syndrome: a preliminary report.

Autoimmune inner ear disease was first described by McCabe in 1979. The diagnosis is supported by cell-mediated immune responses to inner ear membrane antigen stimulation. Cogan's syndrome consists of vestibuloauditory dysfunction, ocular inflammation, and nonreactive serologic tests for syphilis. The ocular disease can be controlled by steroids; unfortunately, some patients ultimately become totally deaf. An autoimmune etiology has long been suspected but only recently confirmed by McCabe. In our study two patients with Cogan's syndrome were studied for autoimmune inner ear disease with the use of both cellular and humoral immune tests. Results were compared to normal control subjects. On the basis of test results, preliminary conclusions were that (1) the vestibuloauditory symptoms of Cogan's syndrome are autoimmune in origin; (2) the autoimmune process is mediated through cellular rather than humoral (antibody) pathways; (3) systemic steroids may suppress positive test results; and (4) test results are more likely to be positive when symptoms are acute. Therapeutic implications are significant: the addition of cytotoxic drugs to steroids in selected cases may help prevent total deafness that otherwise might be inevitable.

Anterior uveitis and multiple sclerosis.

Three patients with clinically definite multiple sclerosis and uveitis were studied. The uveitis presented as inflammation of the anterior segment of the eye (iridocyclitis) and was characterized by large keratic precipitates and posterior synechiae, consistent with a granulomatous iridocyclitis. Clinical and laboratory evidence militated against other central nervous system diseases often associated with uveitis including neurosarcoidosis, Behçet's syndrome, Vogt-Koyanagi-Harada disease, neurosyphilis, and tuberculosis. Further attention should be directed to the possibility of granulomatous anterior uveitis in patients with multiple sclerosis.

Effects of acetazolamide on infantile nystagmus syndrome waveforms: comparisons to contact lenses and convergence in a well-studied subject.

AIM: To determine if acetazolamide, an effective treatment for certain inherited channelopathies, has therapeutic effects on infantile nystagmus syndrome (INS) in a well-studied subject, compare them to other therapies in the same subject and to tenotomy and reattachment (T&R) in other subjects. METHODS: Eye-movement data were taken using a high-speed digital video recording system. Nystagmus waveforms were analyzed by applying an eXpanded Nystagmus Acuity Function (NAFX) at different gaze angles and determining the Longest Foveation Domain (LFD). RESULTS: Acetazolamide improved foveation by both a 59.7% increase in the peak value of the NAFX function (from 0.395 to 0.580) and a 70% broadening of the NAFX vs Gaze Angle curve (the LFD increased from 20° to 34°). The resulting U-shaped improvement in the percent NAFX vs Gaze Angle curve, varied from ~60% near the NAFX peak to over 1000% laterally. The therapeutic improvements in NAFX from acetazolamide (similar to T&R) were intermediate between those of soft contact lenses and convergence, the latter was best; for LFD improvements, acetazolamide and contact lenses were equivalent and less effective than convergence. Computer simulations suggested that damping the central oscillation driving INS was insufficient to produce the foveation improvements and increased NAFX values. CONCLUSION: Acetazolamide resulted in improved-foveation INS waveforms over a broadened range of gaze angles, probably acting at more than one site. This raises the question of whether hereditary INS involves an inherited channelopathy, and whether other agents with known effects on ion channels should be investigated as therapy for this condition.