ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Advances in magnetic resonance (MR) orbital imaging using fat suppression techniques and contrast enhancement have increased our ability to visualize the area of inflammation in patients with optic neuritis. Our understanding of the natural history of optic neuritis continues to expand. The high risk of developing multiple sclerosis (MS) after an episode of optic neuritis has been confirmed with longitudinal studies. The most important predictive factor for the future development of MS continues to be an abnormal MR image at presentation. Treatment with intravenous steroids temporarily reduces this risk but has no effect on visual outcome. Although subjective visual complaints are common, objective measures of vision show only mild loss in most patients.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Acute loss of vision due to anterior ischemic optic neuropathy, both arteritic and nonarteritic, demands investigation and where indicated, treatment as an emergency. While advances continue in the understanding of the pathophysiology and investigation of arteritic anterior ischemic optic neuropathy, the nonarteritic form presents a major therapeutic problem, particularly in the absence of a satisfactory clinical technique for the measurement of optic nerve head blood flow. Because of steroid resistance and side effects of chronic steroid therapy in giant cell arteritis, alternative immunosuppressive agents are being explored. In nonarteritic ischemic optic neuropathy, etio-logic factors such as activated protein C resistance raise the possibility of evaluation for prothrombotic states, while calcium channel blockers offer prospects for the relief of ischemic effects at the cellular level.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Congenital optic nerve anomalies are not as rare as was once thought. Visual prognosis depends on the type of anomaly present. Both central nervous system and systemic abnormalities have been associated with congenital optic nerve anomalies. Therefore, correct diagnosis has important visual and systemic implications. Congenital optic nerve anomalies are distinguished by the optic disc and peripapillary retinal appearance. In general, these anomalies can be grouped by abnormalities of optic disc size or conformation and by the presence of tissue not usually present at the disc.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The development of papilledema requires high cerebrospinal fluid (CSF) pressure in the distal optic nerve sheath, elevation of the pressure in the central retinal vein, and impaired perfu-sion of the neurons as they traverse the lamina cribrosa. Pseudotumor cerebri (PTC) is a syndrome defined by four criteria: 1) Increased intracranial pressure, 2) normal or small ventricles on neuroimaging, 3) no evidence of an intracranial mass, and 4) normal CSF composition. Elevated intracranial venous pressure is thought by some authors to be the “universal mechanism” of PTC of varying etiologies. The reason obesity predisposes to idiopathic PTC is unclear, but one mechanism proposed is that central obesity raises intra-abdominal pressure, which increases pleural pressure and cardiac filling pressures, which impede venous return from the brain, leading to increased intracranial venous pressure and increased intracranial pressure. Both optic nerve sheath fenestration (ONSF) and lumboperitoneal shunting (LPS) may improve vision and prevent deterioration of vision in patients with PTC. Both procedures have their advantages and disadvantages, but until a prospective, randomized study comparing ONSF with LPS for PTC is performed, the question of which surgical procedure is best for the treatment of PTC remains unanswered.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

This review focuses on neuro-ophthalmic disorders caused by trauma. Most articles discussed were published after 1995. The review is divided into sections according to the anatomical sites that can be affected by trauma and lead to neuro-ophthalmic symptoms. The topics are the oculomotor nerves and the facial nerve, the cavernous sinus, the orbit, the optic nerve, and the brain. Treatment options are discussed, including strabismus surgery, orbital reconstruction, and medical as well as surgical treatment of traumatic optic neuropathy.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Higher cortical visual function continues to be explored with both lesion and functional imaging studies. Studies with functional MRI confirm that the fusiform gyri are involved in color and face perception, and show multiple regions participating in motion perception, including V5, V3A, and a new area, the kinetic occipital region. There were numerous blindsight reports, including studies of spatial summation and “inhibition of return,” and a refutation of the argument that blindsight is merely a “criterion shift.” However, other studies failed to find blindsight-like ocular motor responses to moving stimuli. Occipitotemporal lesions were found to cause defects in perception of both first-and second-order motion. The psychophysical impairments of the motion-blind patient LM were shown to be similar to those of monkeys with V5 ablations, suggesting a close homology between this monkey visual area and the human motion area in the lateral occipitotemporal cortex.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Recent investigations in ocular motility have shed light on the anatomical and physiological mechanisms that govern smooth pursuit, saccades, and the vestibulo-ocular reflex in normal humans and patients with neurological disorders. Functional neuroimaging and transcranial magnetic stimulation have been used in normal human subjects to draw parallels with basic investigations in animals. Quantitative studies of eye movement disorders in patients with focal brain dysfunction have added to our understanding of human pathophysiology. Finally, some of the most practical of recent work has been aimed at developing therapies to alleviate the functional limitations caused by abnormal eye movements.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Technical developments in magnetic resonance imaging of the brain and orbits provide a challenge to radiologists and practicing clinicians alike. Several new trends in brain imaging are reviewed, including fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), and perfusion and functional magnetic resonance imaging. These techniques are increasingly used in the clinical environment. Two innovative magnetic resonance techniques for imaging the orbit are also reviewed.

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:1040-8738    

出版商:OVID    

年代:1998

数据来源: OVID