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At least 73 records · Page 4Linked to original sources
PubMed1988

Magnetic resonance imaging of the optic nerve in optic neuritis.

Magnetic resonance imaging (MRI) of the optic nerves using the STIR (short inversion time inversion recovery) sequence was performed in 37 adult patients with a recent or past attack of optic neuritis. MRI revealed high-signal regions in 84% of symptomatic and 20% of asymptomatic nerves. The mean longitudinal extent of lesions was 1 cm. Slow or poor visual recovery was associated with more extensive lesions, or lesions within the optic canal. Disk swelling was usually associated with anterior lesions but also occurred with lesions in the canal. Visual evoked potentials were even more sensitive than MRI in detecting lesions and are still the investigation of choice in suspected demyelinating disease involving the optic nerve.

Adult↗
PubMed2001

Histopathology and ultrastructural examination of optic nerve sheath biopsies after optic nerve sheath decompression with and without mitomycin.

PURPOSE: We chose to compare histologically and ultrastructurally changes in the optic nerve sheath after optic nerve sheath decompression, initially after a second surgery and after treatment with mitomycin-C. The mechanism by which optic nerve sheath decompression alleviates papilledema can be further understood in consideration of the results. METHODS: Tissue was obtained by biopsy from 3 first-time surgical and 4 reoperative cases with and without mitomycin-C in patients with idiopathic intracranial hypertension. The sheaths were fixed in a mixture of 2% paraformaldehyde and 2% glutaraldehyde, osmicated and dehydrated in a series of ethanol, and finally embedded in epon. Tissue blocks were sectioned at 1 microm and stained with both PPD and toluidine blue. Thin sections were examined by transmission electron microscopy. RESULTS: Normal meningeal tissue obtained at the time at optic nerve sheath decompression consisted mainly of collagen, closely packed and roughly parallel to the axis of the optic nerve. Collagen deposition seen in scar tissue after secondary optic nerve sheath decompression was extremely disorganized and irregular, with the individual fibers laid down seemingly at random. There was little sense of layering or of parallel arrays. Mitomycin-C appeared to influence collagen deposition in such a way that the collagen was more regularly packed and more closely resembled unoperated tissue. CONCLUSIONS: The regular well-organized collagen packing seen in normal sheath tissue is disrupted and replaced by less organized but compact scar tissue after optic nerve sheath decompression. With mitomycin use, more regular collagen packing closely approximating that found in unoperated sheath occurs. This configuration of fibers lends support for the filtration mechanism of optic nerve sheath decompression in treating papilledema.

Antibiotics, Antineoplastic↗
PubMed1987

Nervus terminalis, olfactory nerve, and optic nerve representation of luteinizing hormone-releasing hormone in primates.

The luteinizing hormone-releasing hormone (LHRH) system was examined immunocytochemically in olfactory bulbs of adult monkeys, including two New World species (squirrel monkey, Saimiri sciureus and owl monkey, Aotus trivirgatus) and one Old World species (cynomolgus macaque, Macaca fasciculata), and in the brain and nasal region of a fetal rhesus macaque Macaca mulatta. LHRH neurons and fibers were found sparsely distributed in the olfactory bulbs in all adult monkeys. There was more LHRH in the accessory olfactory bulb (which is absent in Old World monkeys). In the fetal macaque there was a rich distribution of LHRH neurons and fibers along the pathway of the nervus terminalis, anterior and ventral to the olfactory bulb, and in the nasal septum, with fibers branching into the olfactory epithelium. In addition, there were LHRH neurons and fibers in the optic nerve.

Animals↗
PubMed1996

Optic nerve glioma mimicking an optic nerve meningioma.

The case is described of an optic nerve glioma, mimicking an optic nerve meningioma in a man aged 41 years. CT, MRI and DSA revealed an enhancing tumor surrounding the optic nerve. Histopathologic examination of the removed optic nerve revealed a centrally located glioma surrounded by normal optic nerve fibres.

Adult↗
PubMed2006

[Three essential elements of glaucomatous optic nerve damage and discrimination of optic nerve rim loss].

Three essential elements of glaucomatous optic nerve damages are optic nerve rim loss, retinal nerve fiber layer defects (RNFLD) and optic disc linear hemorrhages. It's suggested that if there are two positive signs detected among the three elements, the diagnosis of the glaucomatous optic nerve damages can be established. There is no definitely described how to identify optic nerve rim loss in the previous textbooks, therefore it is important to know about the morphological features of the physical optic nerve rim and influence factors before discrimination of optic nerve rim loss. Most of physical optic nerve rim are in accordance with ISNT rule, physical large optic cups are also accord with ISNT rule. Exceptional cases exist in two patterns, optic nerve rim loss or normal optic nerve rim morphological variances. The latter includes part of small discs, horizontally oval optic discs, the position of the central retinal vessel trunk and the titled optic discs which affect the morphological feature of optic nerve rim as well. In some small discs, the width of inferior rim is narrower than that of superior rim, therefore, the inferior or the superior rim loss can be evaluated by comparison with nasal rim width. Concerning horizontal oval optic discs, the width of inferior rim and superior rim should be compared to evaluate whether there is the optic nerve rim loss. If those patterns of normal optic nerve rim variances can be recognized, it is not difficult to find the presence of the optic nerve rim loss. However, not all of the optic nerve rim loss is due to glaucomatous optic nerve damages, non-glaucomatous optic nerve damage should be distinguished.

Diagnosis, Differential↗
PubMed2000

Pattern of vascular nonperfusion in retinal venous occlusions occurring within the optic nerve with and without optic nerve head swelling.

OBJECTIVE: To investigate the significance of optic nerve head swelling (ONHS) in relation to the pattern of vascular nonperfusion, visual acuity (VA), and demographic profile in retinal venous occlusions (RVOs) occurring within the optic nerve. METHODS: Cases of RVO occurring within the optic nerve were divided on the basis of the presence (105 cases) or absence (163 cases) of ONHS. This division was performed by examining the color stereo fundus photographs in conditions masked from other clinical parameters. Duration of symptoms before assessment, age, and sex distributions were compared. The vein involved was identified, and the occlusion was confirmed to have occurred within the optic nerve by observing that the vein pierced the lamina cribrosa as a dilated vein. Fluorescein angiographs were examined, and the extent of vascular nonperfusion in the macula and peripheral retina was quantified from grade 1 to grade 4. The extent of break in the perifoveal capillary arcade was graded as 0, less than or equal to 90 degrees, and greater than 90 degrees. Best-corrected VA was assessed using the Snellen chart. RESULTS: The 2 groups were comparable in terms of the duration of the symptoms before examination. The mean age was significantly younger in the group with ONHS (58.3 vs 65.1 years, P<. 001). Age distribution by sex demonstrated a higher proportion of men younger than 50 years in the ONHS group (19.1% vs 8.6%, P =.01). The group without ONHS involved the papillary vein more frequently (31.3% vs 17.1%, P =.01). The respective proportions of grade 1, 2, 3, and 4 vascular nonperfusion in the macula were 90.5%, 9.5%, 0%, and 0% in the ONHS group, and 62.6%, 14.7%, 13.5%, and 9.2% in the group without ONHS (P<.001). The corresponding proportions for the peripheral retina were 90.4%, 8.7%, 0%, and 1.0% in the ONHS group, and 62.7%, 13.0%, 18.0%, and 6.2% in the group without ONHS (P<.001). In 64.6% of cases with ONHS and 42.9% of cases without, the perifoveal arcade was intact. A break greater than 90 degrees in the perifoveal arcade was present in 12.5% of cases with and 23.6% of cases without ONHS (P =.004). The median VA was significantly better in the ONHS group (6/24 vs 6/48, P =.005). CONCLUSIONS: The RVOs occurring within the optic nerve can be subdivided into 2 distinct groups on the basis of ONHS. The presence of ONHS is associated with younger age, less severe vascular nonperfusion, and better VA. This is consistent with a retrocribrosal site of occlusion, which has access to the pial plexus that can provide collateral channels for retinal venous drainage.

Adult↗
PubMed1978

[Correlation between conduction velocities in fibers of the optic nerve and optic radiation in cats].

The responses of dorsal lateral geniculate body units to striate cortex and optic chiasm stimulation were examined in cats immobilized with d-tubocurarine. A high correlation between antidromic responses to striate cortex and orthodromic responses to optic chiasm stimulation was found (r=0.895; P=0.01). 9% of neurons responded antidromically to optic chiasm stimulation indicating the existence of centrifugal fibres in the optic nerve. The functional significance of time dispersion of the afferent volley in visual system is discussed.

Animals↗
PubMed1990

Immunological evidence that the neural adhesion molecule L1 is expressed in fish brain and optic nerve: possible association with optic nerve regeneration.

In the mammalian peripheral nervous system (PNS), expression of the neural adhesion molecule L1 on Schwann cells and neurons has been correlated with axonal growth during development and regeneration. The present study was undertaken to examine whether a similar correlation exists between a lesion-induced increase of L1 expression and regenerative capacity in the central nervous system (CNS). The fish optic nerve was used as a model for a successfully regenerating region of the CNS. Immunochemical and immunohistological experiments carried out with immunoaffinity purified polyclonal antibodies, generated against L1 from mouse brain, showed that carp optic nerve and brain, but not liver, contained L1 immunoreactivity. Western blot analysis of brain tissue yielded one distinct band at 200 kDa, while a double band at 200 kDa and two low-molecular weight bands at 120 and 100 kDa, possibly degradation products, were seen in the optic nerve. Immunohistological examination of normal optic nerves revealed L1 immunoreactivity, predominantly associated with connective tissue boundaries of nerve fascicles and with blood vessels, as well as inside axonal fascicles. L1 immunoreactivity was increased by 25%, 8 days after crushing of the optic nerve, as determined by radioimmunoassay on a nerve segment distal to the site of injury and compared with untreated control nerves. Increased levels of L1 were also seen by immunohistology and found to be predominantly associated, as in the normal nerve, with connective tissue boundaries and blood vessels. These observations suggest that a lesion-induced increase in L1 expression in the fish optic nerve is associated with axonal regrowth in the CNS.

Animals↗
PubMed2003

Delayed optic nerve decompression for indirect optic nerve injury.

OBJECTIVE: To test the efficacy of delayed optic nerve decompression in traumatic optic nerve injury. STUDY DESIGN: Critical analysis of Proforma-based, prospectively accrued data of all cases with injury to surgery interval of greater than 2 weeks. METHODS: Thirty-five cases with a median injury to surgery interval of 56 days (range, 16-374 d). Surgical decompression was undertaken only in cases that continued to have poor vision after treatment with steroids in conventional doses (1 mg/kg prednisolone). Pre- and postoperative visual acuity measurements were converted to the logMAR scale of visual acuity and the percentage of visual improvement was calculated. RESULTS: Surgery was universally unrewarding in all 9 cases with persistent and complete blindness of greater than 2 weeks and no response to steroid therapy. Of the cases with some residual vision, 20 of 26 cases improved (mean percentage improvement, 41.0 +/- 5.7%). Cases were categorized on the basis of the injury to surgery interval into groups of 2 weeks to 2 months, 2 months to 4 months, and greater than 4 months. No significant difference was demonstrated in the probability or quantum of improvement in these groups (P =.97). CONCLUSIONS: Optic nerve decompression remains useful as a salvage procedure for conventional dose steroid failed cases of traumatic optic neuropathy. In cases that are not completely blind, vision can be improved even when surgery is undertaken a few months after the injury.

Adolescent↗
PubMed2001

Optic cup enlargement followed by reduced optic nerve head circulation after optic nerve stimulation.

PURPOSE: To investigate changes in optic nerve head (ONH) circulation, visual evoked potentials (VEPs), and ONH cupping after stimulation of the optic nerve. METHODS: Electrodes were fixed above the optic chiasma in rabbits under general anesthesia. Screw-type electrodes for VEP recording were fixed on the dura. ONH circulation, intraocular pressure (IOP), and blood pressure (BP) were measured after the passage of a current of 0.1 mA for 0.1 second (weak stimulation), 1 mA for 1 second (moderate), 5 mA for 10 seconds (strong), or 25 mA for 10 seconds (severe). Normalized blur (NB), indicative of tissue blood flow and velocity, was measured in the ONH after each stimulation, by using a laser speckle circulation analyzer. Changes in VEP and ocular fundus were also recorded. The ratio of cup area (CA) to disc area (DA) was measured before and 4 weeks after stimulation. After all experiments, the ONH was histologically examined. RESULTS: Weak stimulation increased NB in ONH for 10 minutes, whereas strong or severe stimulation significantly decreased NB for a longer time, in a dose-dependent manner. BP showed no significant change, except with severe stimulation. IOP was not significantly changed. VEP amplitude was reduced 30 minutes after strong stimulation. The CA-to-DA ratio was significantly increased 4 weeks after strong stimulation. In some rabbits, disc hemorrhage occurred, followed by enlargement of disc cupping, with slight gliosis. CONCLUSIONS: Electrical stimulation of the optic nerve changed ONH circulation and VEPs and increased disc cupping. This technique warrants further investigation as an experimental model for normal-tension glaucoma.

Animals↗
PubMedDate not supplied

[Revascularization decompression of the optic nerve: a new surgery of the optic nerve in progressive glaucomatous optic neuropathy].

A new operation on the optic nerve scleral canal, revascularization compression of the optic nerve, was carried out in 21 patients (21 eyes) in order to improve the visual functions and stabilize the glaucomatous process. The operation combines the advantages of decompression of the optic nerve by dissection of the posterior scleral ring with creation of an additional source of blood supply to the optic nerve from the myovascular bundle of the internal rectal muscle. Good functional effect and notable improvement of hemoperfusion of the optic nerve and retina were attained (period of observation up to 2 years). The degree of visual field extension correlated with the degree of increase in hemoperfusion values. Comparative analysis showed a higher functional efficiency of revascularization decompression of the optic nerve in comparison with optic nerve decompression, which is due to a more essential improvement of ocular hemoperfusion.

Aged↗
PubMed2005

Optic nerve glioma and optic neuritis mimicking one another: case report.

OBJECTIVE AND IMPORTANCE: The clinical and radiographic presentations of optic nerve gliomas and optic neuritis are for the most part distinct and their diagnoses straightforward. We present two cases illustrating the occasional difficulty one can encounter in distinguishing neoplastic from inflammatory optic neuropathies. CLINICAL PRESENTATION: Patient 1 is a 17-year-old girl who presented with acute onset of pain and rapidly progressive visual loss in the right eye. Patient 2 is a 38-year-old man who presented with painless progressive visual loss in the left eye. INTERVENTION: Patient 1 was initially diagnosed with idiopathic retrobulbar optic neuritis. Interval increase of the optic nerve on magnetic resonance imaging prompted a biopsy of the optic nerve, which revealed a pilocytic astrocytoma. Patient 2 was found to have left optic nerve enhancement most consistent with an optic nerve glioma. Before a biopsy, the patient spontaneously improved without treatment, indicating an inflammatory process. CONCLUSION: Differentiating between optic nerve neoplasm and inflammation may be difficult. On occasion, the classic clinical finding of pain with eye movement and the radiographic finding of enlargement and enhancement of the optic nerve may be misleading. Open biopsy of the optic nerve is indicated only after a completely negative metabolic, infectious, and inflammatory workup; interval increase of the optic nerve on magnetic resonance imaging; and failure of the patient to recover vision.

Adolescent↗