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PubMed2005

Diagnosis and treatment of retrobulbar haematomas following blunt orbital trauma: a description of eight cases.

Retrobulbar haematoma following blunt orbital trauma is a rare, but potentially serious, complication, since it can evolve rapidly from visual impairment to permanent loss of vision. This sight-threatening situation most commonly arises from orbital bleeding accompanying undisplaced fractures of the orbital walls, an event that increases the pressure inside the orbit and results in vascular damage to the optic nerve. The clinical presentation includes pain, exophthalmos with proptosis, and internal ophthalmoplegia, with impairment or loss of the pupillary reflex. A thin-layer orbital CT scan is an essential diagnostic aid. Any delay between the onset of symptoms and treatment can have a significant effect on functional recovery. Therapy is based on orbital decompression, via different surgical approaches, with the intention of reducing the pressure on the nerve and vascular structures inside the orbit. This paper presents eight cases of retrobulbar haematoma and their follow-up, in detail.

Adult↗
PubMed2002

Tuberculum sellae meningioma: a report on management on the basis of a surgical experience with 70 patients.

OBJECTIVE: The surgical strategies and outcomes for 70 patients operated on for tuberculum sellae meningioma were analyzed retrospectively. The analysis was based on factors that probably determined the difficulties encountered during surgery, assisted in predicting the extent of resectability, and helped in predicting the surgical outcome. METHODS: Seventy patients with tuberculum sellae meningiomas were operated on in the neurosurgery department at King Edward Memorial Hospital and Seth Gordhandas Sunderdas Medical College, Bombay, India, between 1991 and May 2001. The patients were analyzed retrospectively on the basis of clinical and radiological factors that appeared to affect the outcome. Each factor was given points, and for each tumor, the points were added to obtain a score. On the basis of the score, the tumors were then divided into three grades. The grades determined the difficulties that could be anticipated during surgery. The majority of patients were operated on by use of unifrontal craniotomy on the side of worse vision by standard dissection techniques. RESULTS: Total tumor resection was achieved in 59 patients, and subtotal tumor resection with less than 7% of tumor left behind was achieved in 11 patients. All patients with subtotal resection had higher-grade tumors. Preoperative visual status had a bearing on the visual outcome after surgery. Four patients were misdiagnosed as having a pituitary tumor. Two patients died in the immediate postoperative period. The average follow-up was 46 months (range, 6 mo to 9 yr). There was symptomatic recurrence in one patient in whom a subtotal resection had been performed. CONCLUSION: The extent and duration of visual symptoms, encasement of the anterior cerebral artery complex, and size of the tumor were the more important factors that affected the surgery. The grading system gave a reasonable assessment concerning the possible surgical problems.

Adult↗
PubMed1985

Neurosurgical involvement in tumors of the orbit.

The neurosurgeon has a great deal to offer in the therapy of orbital tumors. Dr. Dandy's supposition that all orbital tumors could be approached by the intracranial route is certainly correct, but technical advances have made the medial and lateral approaches to the orbit more useful for most tumors which are confined to the orbit (22, 25). For those which involve the posterior orbit and canal and have intracranial extensions, the intracranial approach is excellent. Since Dandy's first description of the procedure in 1922, there have been 29 patient reports concerning the results of transcranial canalicular decompression for non-traumatic causes. The most common diagnosis was meningioma (15), and other tumor diagnoses were fibrous dysplasia (7) and hemangioma (2). One-third of the patients were improved; one-third had vision stabilized; and one-third were made worse by surgery. Modern techniques with the microscope and high speed drill have greatly improved these results. Our own experience in the decompression of 15 canals in 11 patients is as follows. There were six patients with meningioma, and two were bilateral. Three patients were found to have a vascular dolichoectasis and one patient had an hemangioma, and in two patients no compression was identified. Immediately postoperatively, two-thirds of the patients were improved, and only one eye (representing 6.7% of the nerves decompressed) was worsened. This resulted from an attempt to totally remove an adherent sheath meningioma. Long-term follow-up median 34 months has demonstrated maintenance of these gains. Eighty percent of the patients have improved or remained stable. These data indicate that the procedure described can be done safely without major risk of visual loss. The neurosurgeon should play an increasingly important role in the evaluation and therapy of posteriorly placed orbital tumors and unexplained compressive optic neuropathy.

Brain Neoplasms↗
PubMed2026

Spatial inheritance patterns across maize ears are associated with alleles that reduce pollen fitness.

Often, more pollen grains land on recipient flowers than there are ovules to fertilize. Consequently, the haploid male gametophyte engages in post-pollination competition, one way that pollen genotype can influence inheritance. The maize (Zea mays subsp. mays L.) inflorescence (ear), with its elongated stigma and style structures (silks), has a conspicuous spatial heterogeneity, with longer silks at the base of the ear than at the apex. To evaluate the hypothesis that alleles with reduced pollen fitness influence the spatial distribution of progeny genotypes along the ear, we developed an updated phenotyping platform that maps fluorescently marked mutant (Ds-GFP) kernel phenotypes on the ear via an implementation of the Faster R-CNN machine vision model (EarVision.v2) and a statistical pipeline that evaluates the relationship between kernel position and transmission ratio (EarScape). Our dataset (1384 ears) represents 58 Ds-GFP insertion alleles. None of the 48 alleles with Mendelian inheritance showed any significant spatial trend. In contrast, 50% of alleles with a pollen-specific transmission defect (5/10) exhibited significant spatial effects. An insertional mutant of the gene encoding a putative actin-binding protein, base-to-apex gradient1* (bag1*), is associated with decreased mutant transmission at the ear base relative to the apex. Surprisingly, a mutant allele of another pollen-expressed gene (Zm00001eb236740) generates the opposite trend, decreased mutant transmission toward the ear apex; and two mutant alleles of the sperm cell attachment factor gamete expressed2 (gex2) can produce ears with transmission highest at both base and apex. We conclude that pollen fitness mutants cause unexpectedly diverse spatial patterns of progeny genotypes.

Zea mays↗
PubMed1999

[Fronto-naso-ethmoido-sphenoido-maxillo-orbital mucocele with ophthalmologic presentation].

PURPOSE: We present a case of a large mucocele pressing the orbit forward and compared our findings with those reported by others. CASE REPORT: A 23-year-old woman was examined for an inflammatory tumor of the internal canthus. She had a 6/10 vision loss of the left eye, diplopia, and non-axial exophthalmos. CT scan and magnetic resonance imaging evidenced a huge sinus mucocele behind the orbit. Surgery using the paralateronasal approach was performed. Pathology confirmed the diagnosis of mucocele. DISCUSSION: Ophthalmic complications of mucoceles result from tumor growth leading to compressive optic neuropathy or even compression of the chiasma. A sinus mucocele should be suspected upon indirect clinical signs and lead to neuroradiological explorations. Magnetic resonance imaging reveals iso- or high signals on T1-weighted sequences and high signal on T2-weighted sequences. MRI evidences intracranial or orbital extension. CT scan reveal the degree of bone erosion. Prognosis is favorable after surgical treatment. It is important to correctly diagnose mucocele on the basis of clinical and neuroradiological findings in order to propose early surgery and prevent permanent visual loss by compressive optic neuropathy.

Adult↗
PubMed2002

Perception of verticality after recent cerebral hemispheric stroke.

BACKGROUND AND PURPOSE: Perception of the subjective visual vertical (SVV) is affected by cerebral hemispheric lesions. Knowledge of this disturbance is of interest for the study of its possible relation to balance disturbances. There is still uncertainty about the possible effects of a visual field defect and of the side and site of the lesion. This study was conducted to assess SVV with the head upright or tilted and to explore its relation to a visual field defect, visuospatial neglect, and the site of lesion. METHODS: Forty patients with hemiplegia after a recent hemispheric stroke (20 with left and 20 with right stroke) were studied. The site of the lesion was determined on CT scan, with special attention focused on the vestibular cortex. A neurological examination with determination of the visual field and visual neglect was conducted before SVV was tested. Subjects sat in a dark room and adjusted a luminous rod to the vertical position. Measures were repeated with binocular and monocular vision and with the head upright or tilted to the right or left. RESULTS: SVV was abnormally deviated in 23 of 40 patients (57%). The deviation was significantly greater among patients with a right or left hemispheric lesion than among healthy controls (-2.2 degrees and 1.5 degrees versus 0.2 degrees ); the same applied to the range of uncertainty (7.6 degrees and 4.7 degrees versus 1.9 degrees ). SVV deviation was not significantly related to the location of the lesion but was closely related to visuospatial neglect. The "E" effect observed in controls with the head tilted, ie, an SVV shift in the direction opposite to the head tilt, was not observed in hemiplegic patients with the head tilted toward the nonparetic side. CONCLUSIONS: Recent hemispheric stroke affects SVV perception, which is closely correlated to visuospatial neglect. It is suggested that the E effect might be mediated by the stretching of the somatosensory structure of the neck.

Brain↗
PubMed1987

[Vascular compression neuropathy of the optic nerve by sclerotic internal carotid artery].

Although mechanical compression of the optic nerve by a dilated and/or tortuous sclerotic intracranial internal carotid artery is occasionally reported as an etiology for impairment of vision and visual field, early diagnosis of such condition has been hampered by the lack of characteristic neuro-ophthalmological and neuroradiological findings. The review of 35 previously reported cases (60 eyes) including ours showed that 41% out of the 34 operated eyes were improved neurologically by the decompressive procedure, while it was in 27% out of the 26 undecompressed or non-operated eyes. These unsatisfactory operative results are considered mainly due to the failure of early diagnosis. In order to investigate the relationship between the carotid artery and optic nerve, we proposed a method of angiographical projection consisting of the straight view along the long axis of the optic canal. By this projection, it is possible to detect a supero-medial enlargement and/or dislocation of the cisternal portion of the internal carotid artery. The addition of metrizamide CT cisternography which clarifies the relationship of the optic nerve, chiasm and internal carotid artery in the supersellar cistern may further provide an useful clue for the diagnosis of this condition.

Aged↗
PubMed1995

New Spielmeyer-Vogt variant with granular inclusions and early brain atrophy.

Three females in 2 families were originally diagnosed with Spielmeyer-Vogt disease (SVD). The clinical course was different from SVD, with vision well preserved until age 10 years, and learning rather than visual difficulties the marker at the onset. Later, regression was unusually rapid, including global dementia, blindness, aphasia, and finally loss of self-feeding and ambulation between ages 12-18 years. MRI scan in patient 3 documented brain atrophy between ages 8-10 years. Position Emission Tomography (PET) scanning with fluorodeoxyglucose in patients 2 and 3 showed diffusely decreased or absent cortical glucose metabolism, comparable at ages 12 and 18 years, respectively, to the results found in the oldest typical SVD case tested at age 29 years. Fine granular inclusions, instead of the expected fingerprint inclusions, were demonstrated by electron microscopy of lymphocytes, conjunctiva, and skin. Usual markers on chromosome 16p12 were not present in the first family tested. The clinical course, with nonspecific initial behavior difficulties, late onset of visual decline followed by fast global regression, progressive brain atrophy, decreased cortical glucose utilization as shown by PET scanning, and granular tissue inclusions, suggest a genetic variant of SVD.

Adult↗
PubMed2000

Disturbances of spatial vision and object vision correlate differently with regional cerebral glucose metabolism in Alzheimer's disease.

There is evidence of two neuronal systems for visual cognition which are referred to as spatial vision and object vision. We subjected 49 patients with mild-to-moderate probable Alzheimer's disease (AD) to tasks associated with these two types of visual cognition. Visual counting was employed as a task to assess visuospatial recognition. Identification of overlapping figures and discrimination of visual forms were used as visuoperceptual tasks that require an ability to recognize objects. Regional cerebral glucose metabolism (rCMRglc) of the subjects was also determined by positron emission tomography. Multivariate statistics controlling for the confounding factors assessed the correlation between the task performances and the rCMRglc. The visual counting score significantly correlated with the metabolic rate of the bilateral inferior parietal lobules. On the other hand, the scores of the visuoperceptual tasks significantly correlated with the metabolic rate of the right middle temporal gyrus and the right inferior parietal lobule. The present study showed that visuospatial disturbance was related to bilateral parietal metabolism, and that visuoperceptual disturbance was related to right temporo-parietal metabolism in patients with mild-to-moderate AD.

Aged↗
PubMed1996

SPECT findings in an unusual case of visual hallucinosis.

A 64-year-old right-handed man acutely developed elementary visual hallucinations (monochromatic, moving geometrical figures), visual illusions (distortion of the right side of faces) with achromatopsia and blurred vision restricted to the left visual hemi-field. CT of the brain before and after administration of contrast medium and a repeat examination 2 months later showed no abnormalities, while brain mapping (power analysis of EEG) demonstrated theta wave slowing of the curve over the posterior part of the right hemisphere. 99mTC HMPAO SPECT of the brain, however, demonstrated an area of definite focal hypoperfusion in the right occipito-temporal region. Echo-Doppler-duplex and continuous wave examination of the cervical arterial blood vessels disclosed bilateral discrete atheromatous plaques that did not affect the blood flow. Transoesophageal echocardiography demonstrated slight mitral valve insufficiency. Cerebral angiography showed an occlusion of the right posterior cerebral artery. After the visual hallucinations had subsided, SPECT showed partial normalization of the right occipito-temporal perfusion. In the absence of CT evidence for a structural lesion in the clinically suspected areas, only functional imaging revealed an obviously significant lesion. This case furthermore demonstrates that SPECT can contribute to the identification of the pathophysiology underlying visual hallucinosis.

Brain↗
PubMed2006

Performance characterization of the dynamic programming obstacle detection algorithm.

A computer vision-based system using images from an airborne aircraft can increase flight safety by aiding the pilot to detect obstacles in the flight path so as to avoid mid-air collisions. Such a system fits naturally with the development of an external vision system proposed by NASA for use in high-speed civil transport aircraft with limited cockpit visibility. The detection techniques should provide high detection probability for obstacles that can vary from subpixels to a few pixels in size, while maintaining a low false alarm probability in the presence of noise and severe background clutter. Furthermore, the detection algorithms must be able to report such obstacles in a timely fashion, imposing severe constraints on their execution time. For this purpose, we have implemented a number of algorithms to detect airborne obstacles using image sequences obtained from a camera mounted on an aircraft. This paper describes the methodology used for characterizing the performance of the dynamic programming obstacle detection algorithm and its special cases. The experimental results were obtained using several types of image sequences, with simulated and real backgrounds. The approximate performance of the algorithm is also theoretically derived using principles of statistical analysis in terms of the signal-to-noise ration (SNR) required for the probabilities of false alarms and misdetections to be lower than prespecified values. The theoretical and experimental performance are compared in terms of the required SNR.

Algorithms↗
PubMed1993

Three modes of spatiotemporal preprocessing by eyes.

1. Optimal spatiotemporal filters for early vision were computed as a function of signal-to-noise ratio (SNR) and alpha, a parameter defined as the ratio of the width of the probability distribution of velocities as perceived by the naturally behaving animal, and the characteristic velocity of the photoreceptors (the velocity required to move across a receptor's receptive field in a receptor's integration time). Animals that move slowly, on average, compared with the characteristic velocity of their photoreceptors have alpha << 1, animals that move fast have alpha >> 1. 2. For alpha << 1, the temporal part of the optimal filter adapts more to different SNRs (light levels) than the spatial part, leading to large adjustments in temporal resolving power and strong self-inhibition at high SNR, but little lateral inhibition. 3. For alpha >> 1, the spatial part of the filter adapts more strongly than the temporal part, leading to strong lateral inhibition at high SNR, and little self-inhibition. 4. For alpha approximately 1, both spatial and temporal properties change about equally much when varying SNR. 5. Varying the width of the angular sensitivity of the photoreceptors shows that for every combination of alpha and SNR there is an optimal width. Visual systems with large alpha need wider angular sensitivities, in particular at low SNR, in order to reach the information maximum than visual systems with small alpha.

Animals↗
PubMed2000

X-linked adrenoleukodystrophy. The Saudi experience.

OBJECTIVES: To evaluate the clinical, biochemical, neuroradiological, and neurophysiological findings of patients with X-linked adrenoleukodystrophy. METHODS: Retrospective study evaluating the data of 10 X-linked adrenoleukodystrophy patients diagnosed at King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia. RESULTS: The common presenting symptoms were deterioration in school performance, vision and hearing, behavioral changes, and seizures. Eight patients survived 1-4 years and one patient 12 years after the initial presentation, while one patient expired. Six patients had the childhood form, 3 had the adolescent form and one had the adrenomyeloneuropathy form. Six are in an advanced stage of the disease and 3 have mild to moderate spasticity. All except 2 manifested moderate to severe dementia with variable degrees of visual loss. Decreased hearing and features of adrenal insufficiency were seen in 7 patients. Very long chain fatty acids were significantly increased in seven and mildly elevated in 2 patients, however the C26 to C22 ratio was increased in all. The characteristic high-signal intensity of parieto-occipital white matter on brain magnetic resonance imaging T2-weighted images was observed in all patients. Two patients had functional study of the brain, which showed hypometabolic activity in gray and white matter of the occipital lobes. Various neurophysiological abnormalities were detected. The response to different treatment modalities was not promising. CONCLUSION: The disease is more common than had been previously recognized due to phenotypic variability and a wide spectrum of presentations. This report describes various aspects of this disorder and emphasizes the importance of early identification and treatment of asymptomatic but biochemically affected individuals, since all current therapeutic approaches are disappointing if overt neurological abnormalities have been already developed.

Adolescent↗
PubMed1977

Anatomic considerations for computed tomography of the optic chiasm.

When the clinical distinction between lesions of the optic nerves or the chiasm is not apparent, computed tomographic scans should be performed at both 0 degrees and 25 degrees or 35 degrees to the orbital-meatal line (Reid's baseline). The former plane is preferable for the demonstration of the optic nerves or orbital structures, while the latter allows superior visualization of perichiasmatic structures.

Female↗
PubMed1982

Visual loss from cavernous hemangiomas of the middle cranial fossa.

We studied a case of cavernous hemangioma of the middle cranial fossa. This rare tumor, of which only nine prior cases have been recorded, is characterized by insidious visual loss, multiple cranial nerve pareses, proptosis, papilledema, and bitemporal hemianopsia. Pituitary dysfunction has been noted in the more advanced cases. The female-male ratio has been 8:2; ages ranged from 30 to 62 years. The hemangiomas may occur on either side. Contrast-enhanced computed tomography can clearly demonstrate the presence of these lesions, but is not diagnostically specific. High-quality angiograms using magnification and subtraction techniques may show areas of dye retention in the cavernous spaces of the lesion. This tumor is amenable to successful excision, and early removal may prevent progressive visual loss.

Female↗
PubMed1987

Clinical features of ischemia in cerebral arterial border zones after periods of reduced cerebral blood flow.

The clinical syndrome of border-zone ischemia is described in eight patients. Cerebral damage in four occurred during or after cardiac surgery and the other four patients had each experienced a period of severe hypotension. Cerebral blindness and visual disorientation are the most regular features and are produced by ischemic lesions in the parieto-occipital region, the common border-zone territory between all three arterial territories. Some patients show bibrachial sensorimotor impairment and a disturbance of volitional saccadic eye movement caused by more anteriorly placed ischemia in the anterior-middle artery border zone. Some show a temporary dyslexia/dysgraphia and memory defect related to bilateral parietotemporal lesions in the middle-posterior border zone.

Adult↗
PubMed1988

Posterior cortical atrophy.

Five patients had progressive dementia heralded by disorders of higher visual function. All eventually developed alexia, agraphia, visual agnosia, and components of Balint's, Gerstmann's, and transcortical sensory aphasia syndromes. Memory, insight, and judgment were relatively preserved until late in the course. Predominant parieto-occipital atrophy was demonstrated on both computed tomography and magnetic resonance imaging in two of the patients; posterior circulation was normal by angiography in the three studied. To date, no pathologic specimen is available for study; speculations on the underlying pathologic condition include an atypical clinical variant of Alzheimer's disease, a lobar atrophy analogous to Pick's disease, or some previously unrecognized entity.

Aged↗