Optic disc duplication or coloboma?

AIM: To describe lesions resembling optic disc duplication and highlight their unusual visual fields. The authors also report the first case of pseudo-duplication of the optic disc with overlying retinal nerve fibre layer. METHODS: Retrospective, non-comparative review of case notes. Humphrey visual fields and OCT-3 imaging were performed. RESULTS: All 11 cases represented peripapillary chorioretinal coloboma, some of which lie superior to the optic disc. A double blind spot or superior hemifield defects can be demonstrated by automated visual field testing. CONCLUSION: Clinical examination and identification of bridging retinal vessels from the true optic disc to the second pseudo disc can usually avoid unnecessary invasive and non-invasive investigations.

Optical coherence tomography of superior segmental optic hypoplasia.

AIM: To describe optical coherence tomography (OCT) images of superior segmental optic hypoplasia (SSOH). METHODS: Five patients (two men and three women, ages 10-45 years) presented with ophthalmoscopic features and visual field defects of SSOH. All affected eyes had good visual acuity and inferior altitudinal or inferonasal visual field loss. The mothers of three patients had type 1 diabetes mellitus. OCT (Humphrey Instrument, CA, USA) was used to evaluate tomographically the optic disc and peripapillary retina of both eyes of each patient. Control data on retinal nerve fibre layer (RNFL) thickness were obtained from 13 normal eyes, one eye each from 13 normal subjects. RESULTS: Seven of 10 eyes in patients had SSOH. Scans in the vertical meridian through the affected optic discs showed a superior defect of the optic disc associated with decreased RNFL thickness and, in some cases, an abnormal extension of a complex of retinal pigment epithelium and choroid over the edge of the lamina cribrosa. Circular scans around the seven optic discs revealed various decreases of peripapillary RNFL thickness in the superior quadrants. Vertical scans through the fovea also showed superior thinning of RNFL. Quantitative assessment of the peripapillary RNFL thickness revealed significantly decreased values in the superior quadrants compared to normal eyes. CONCLUSIONS: OCT provides a new tool for quantitative evaluation of optic nerve hypoplasia as exemplified in this study of SSOH. It can reveal minimal degrees of segmental hypoplasia previously undetected.

Vascular compression as a cause of superior oblique myokymia disclosed by thin-slice magnetic resonance imaging.

PURPOSE: To describe a case of superior oblique myokymia in which thin-slice magnetic resonance imaging (MRI) appeared to show vascular compression of the trochlear nerve. METHODS: A 50-year-old woman presented with episodic monocular oscillopsia. Neuro-ophthalmologic examinations showed intermittent intorsional microtremor of her right eye, diagnosed as right superior oblique myokymia. Thin-slice (1.6 mm) MRI, using spoiled gradient recalled acquisition in the steady state, was employed to examine the trochlear nerve in its course through the ambient cistern. RESULTS: Imaging disclosed a branch of the posterior cerebral artery immediately adjacent to the right trochlear nerve. CONCLUSION: These magnetic resonance findings suggest that a cause of superior oblique myokymia may be vascular compression of the trunk of the trochlear nerve.

Spontaneous regression of optic gliomas: thirteen cases documented by serial neuroimaging.

OBJECTIVE: To demonstrate spontaneous regression of large, clinically symptomatic optic pathway gliomas in patients with and without neurofibromatosis type 1 (NF-1). METHODS: Patient cases were collected through surveys at 2 consecutive annual meetings of the North American Neuro-Ophthalmology Society (NANOS) and through requests on the NANOSNET Internet listserv. Serial documentation of tumor signal and size, using magnetic resonance imaging in 11 patients and computed tomography in 2 patients, was used to evaluate clinically symptomatic optic pathway gliomas. All tumors met radiologic criteria for the diagnosis of glioma and 4 patients had biopsy confirmation of their tumors. In 3 patients, some attempt at therapy had been made many years before regression occurred. In one of these, radiation treatment had been given 19 years before tumor regression, while in another, chemotherapy had been administered 5 years before signal changes in the tumor. In the third patient, minimal surgical debulking was performed 1 year before the tumor began to shrink. RESULTS: Spontaneous tumor shrinkage was noted in 12 patients. Eight patients did not have NF-1. In an additional patient without NF-1, a signal change within the tumor without associated shrinkage was detected. Tumor regression was associated with improvement in visual function in 10 of 13 patients, stability of function in 1, and deterioration in 2. CONCLUSIONS: Large, clinically symptomatic optic gliomas may undergo spontaneous regression. Regression was seen in patients with and without NF-1. Regression may manifest either as an overall shrinkage in tumor size, or as a signal change on magnetic resonance imaging. A variable degree of improvement in visual function may accompany regression. The possibility of spontaneous regression of an optic glioma should be considered in the planning of treatment of patients with these tumors.

Bilateral orbital pseudotumor with suprasellar and pulmonary involvement: report of a case.

A 39-year-old man had bilateral proptosis and blurred vision for I week. Computed tomography and magnetic resonance imaging showed signs of bilateral orbital pseudotumor, a suprasellar mass, and pulmonary infiltration. Biopsies from retrobulbar and bronchial sites showed similar inflammatory tissue. His disease resolved with pulsed corticosteroid therapy.

Topless optic disk syndrome without maternal diabetes mellitus.

PURPOSE: To describe four cases of topless optic disk syndrome without maternal diabetes mellitus. METHOD: Four patients had incidentally discovered inferior visual field defects. RESULTS: Ophthalmoscopic examinations in all four patients disclosed superiorly displaced entrances of the central retinal artery and thinning of the superior peripapillary nerve fiber layers. One patient had a superior peripapillary crescent with pallor of the superior disk. These clinical findings were consistent with a diagnosis of superior segmental optic hypoplasia, the topless disk. None of the patients had mothers who had diabetes. CONCLUSIONS: The topless optic disk syndrome can occur in the absence of maternal diabetes mellitus.

Cerebral polyopia with extrastriate quadrantanopia: report of a case with magnetic resonance documentation of V2/V3 cortical infarction.

This is a case report of the occurrence of cerebral diplopia with right-side superior homonymous quadrantanopia in a young woman after chiropractic neck manipulation. Magnetic resonance imaging confirmed an infarct in the left inferior V2/V3 (extrastriate) cortex. The characteristics of the diplopia are illustrated with the patient's drawings, and persisting abnormalities in perception are described in the area of the initial field defect after static (computed) visual field testing yielded normal results.

[Spontaneous regression of familial glioma of the optic nerve in a boy with suspected neurofibromatosis 1 (Recklinghausen's disease)]. / Spontannaia regressiia semeinoi gliomy zritel'nogo nerva u mal'chika s predpolagaemym neirofibromatozom I tipa (bolezn' Reklingauzena). .

A boy with a large intracranial glioma of the optic tract and probable neurofibromatosis of the first type was observed for 8 years since the age of 7 years. A series of MR scans was made over this period. A notable decrease of the tumor size was seen on its signals on the MR scans. This was paralleled by an improvement of the vision acuity, color field, and visual field on the involved eye. Patient's grandmother had an intracranial glioma of the optic nerve with a slight but stable decrease of the visual functions. The tumor shape in the grandmother and grandchild is remarkably similar. This finding in the grandmother and stability of her vision decreased from childhood permit us to propose that the tumor did not develop and even regressed with time.

Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging.

PURPOSE: To demonstrate that currently available magnetic resonance imaging techniques may verify the absence of the abducens nerve in Duane syndrome. METHODS: We performed magnetic resonance imaging in a 36-year-old woman with left Duane syndrome, type 1, using spoiled gradient recalled acquisition in the steady state to obtain high-resolution T1-weighted images through the abducens nerve in its subarachnoid segment. Scans were obtained in the axial plane from the medulla to the midbrain and then reformatted along the plane of the abducens nerve. RESULT: Unilateral absence of the left abducens nerve was verified using magnetic resonance imaging. CONCLUSION: The absence of the abducens nerve in Duane syndrome can be verified by modern magnetic resonance imaging techniques.

Temporal crescent syndrome with magnetic resonance correlation.

BACKGROUND: A young woman with a history of controlled hypertension noted a suddenly decreased peripheral temporal field in the left eye. This occurred after moderate peripartum hypertension. METHOD: A monocular peripheral temporal crescentic defect could be plotted on Goldmann visual fields despite a normal dilated peripheral retinal examination and normal disc appearance. RESULT: A dilated parieto-occipital sulcus could be seen on computed tomography, and magnetic resonance imaging showed changes consistent with atrophy and gliosis in the cuneus, precuneus, and anterior calcarine cortex surrounding the parieto-occipital sulcus. CONCLUSION: By magnetic resonance imaging, this can be seen to comprise less than 10% of the visual cortex, as suggested by the Horton and Hoyt revised Holmes map. The temporal crescent syndrome is a rare monocular retrochiasmatic visual field defect that can be correlated to a lesion along the parieto-occipital sulcus.

Pathogenesis of acute monocular blindness from leaking anterior communicating artery aneurysms: report of six cases.

This report describes six cases of leaking anterior communicating aneurysms, collected over 37 years, that caused acute monocular blindness. In two cases, surgical and pathologic evidence demonstrated the pathogenic mechanism: As the aneurysm enlarges, the down-pointing dome compresses the optic nerve from above and adheres to it. When the aneurysm ruptures through the adherent dome, it bleeds directly into the optic nerve, resulting in severe headache and monocular blindness. The other cases also suggest an alternative mechanism, namely, direct optic nerve compression by the aneurysm.

Superficial siderosis and episodic fourth nerve paresis. Report of a case with clinical and magnetic resonance imaging findings.

We describe a patient with superficial siderosis who had an episodic unilateral fourth nerve paresis. The superficial siderosis was caused by small repeated intraventricular hemorrhages from a periventricular cavernous angioma. T2-weighted magnetic resonance images demonstrated a rim of low signal intensity at the brain surface, characteristic of hemosiderin deposition. These low-signal-intensity deposits included the dorsal brain stem around the anterior medullary velum. We suggest that the hemosiderin deposits affected the proximal portion of the fourth nerve where it contains central myelin and that this in some way caused unstable conduction of nerve impulses through the nerve.

Hemifield slide diplopia from altitudinal visual field defects.

We report two cases in which heteronymous, altitudinal visual field defects resulted in loss of fusion and transient overlap of preserved hemifields. This phenomenon resulted in complaints of diplopia similar to that described as "hemifield" slide previously described by temporal hemianopsias. These cases illustrate that generalized loss of fusion, and not the particular type of hemianopic field defect, is responsible for the symptoms known as hemifield slide.

Reading-evoked visual dimming.

PURPOSE: To carry out a neuroradiologic investigation in a monocular 49-year-old patient who during the past five years described symptoms of dimming of central vision in his left eye, which was provoked only by reading. METHODS: Computed tomography and magnetic resonance imaging were performed. RESULTS: An orbital apex intraconal tumor situated laterally to and above the optic nerve was found. CONCLUSIONS: Reading-evoked visual dimming can be a variant of gaze-evoked amaurosis. The optic nerve displaced laterally and superiorly, and stretched by the act of reading, may be compressed between the tumor above and the contracted inferior rectus muscle inferiorly.