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At least 199 records · Page 11Linked to original sources
PubMed1999

Optic nerve cysticercosis in the optic canal.

The authors present a first case of cysticercosis in the optic canal in a fifteen-year-old female patient. Cysticercosis of the optic nerve is rare. A cyst in the optic canal, beneath the sheath of the optic nerve, has never been reported. The patient presented with rapidly diminishing vision in the left eye, headache and papillitis. A magnetic resonance imaging revealed a cystic lesion at the entrance of the optic canal. Surgery performed was a transcranial orbitotomy which included deroofing of the optic canal and removal of the cyst from under the sheath of the optic nerve. The cyst proved to be cysticercus histopathologically. The outcome was a remarkable visual recovery.

Adolescent↗
PubMed2000

Anterior optic nerve microvascular changes in human glaucomatous optic neuropathy.

The microvascular changes in the anterior optic nerve in human glaucomatous eyes were examined by selective methylmethacrylate microvascular corrosion castings following cannulation of the central retinal artery and posterior ciliary arteries in 11 normal eyes and 9 glaucomatous eyes. The resulting castings were examined with scanning electron microscopy. Microvascular changes were found in the anterior optic nerves of all the glaucomatous eyes with visual function loss. These findings include areas of capillary filling defects within the anterior optic nerve and a decreased numbers of feeding arteriolar vessels to the anterior optic nerve. In the prelaminar and laminar regions, the typical capillary patterns are lost and laminar striations are not present. Juxtapapillary choroidal and retinal avascular areas were also identified in two of the glaucomatous eyes. Selective microvascular corrosion casting is an excellent method to examine the three-dimensional microvasculature of the anterior optic nerve. Microvascular changes in the anterior optic nerve may play a role in the development of glaucomatous optic neuropathy.

Aged↗
PubMed2006

Focusing optics of a parallel beam CCD optical tomography apparatus for 3D radiation gel dosimetry.

Optical tomography of gel dosimeters is a promising and cost-effective avenue for quality control of radiotherapy treatments such as intensity-modulated radiotherapy (IMRT). Systems based on a laser coupled to a photodiode have so far shown the best results within the context of optical scanning of radiosensitive gels, but are very slow ( approximately 9 min per slice) and poorly suited to measurements that require many slices. Here, we describe a fast, three-dimensional (3D) optical computed tomography (optical-CT) apparatus, based on a broad, collimated beam, obtained from a high power LED and detected by a charged coupled detector (CCD). The main advantages of such a system are (i) an acquisition speed approximately two orders of magnitude higher than a laser-based system when 3D data are required, and (ii) a greater simplicity of design. This paper advances our previous work by introducing a new design of focusing optics, which take information from a suitably positioned focal plane and project an image onto the CCD. An analysis of the ray optics is presented, which explains the roles of telecentricity, focusing, acceptance angle and depth-of-field (DOF) in the formation of projections. A discussion of the approximation involved in measuring the line integrals required for filtered backprojection reconstruction is given. Experimental results demonstrate (i) the effect on projections of changing the position of the focal plane of the apparatus, (ii) how to measure the acceptance angle of the optics, and (iii) the ability of the new scanner to image both absorbing and scattering gel phantoms. The quality of reconstructed images is very promising and suggests that the new apparatus may be useful in a clinical setting for fast and accurate 3D dosimetry.

Equipment Design↗
PubMed2003

Transvitreal optic neurotomy for nonarteritic anterior ischemic optic neuropathy.

PURPOSE: To evaluate the role of transvitreal optic neurotomy in the treatment of nonarteritic anterior ischemic optic neuropathy, a scleral outlet compartment syndrome, in which neurovascular compression at the prelaminar and laminar regions of the optic nerve head may play a major role. METHODS: Seven eyes of seven selected patients with severe vision loss (<20/800) from nonarteritic anterior ischemic optic neuropathy underwent transvitreal nasal radial optic neurotomy. The study was not masked and not randomized. Visual acuity and visual fields, when possible, were measured, and fluorescein angiography was performed preoperatively and postoperatively. RESULTS: Four male and three female patients had a mean age of 52.4 years; five had bilateral disease. The mean follow-up was 13 +/- 7 weeks. Mean preoperative visual acuity was 20/2400; mean postoperative visual acuity was 20/250, with an average of 10 lines of improvement. Six of seven patients showed visual improvement. One patient had peripapillary choroidal neovascularization. In two patients with sufficient visual acuity, preoperative visual fields could be obtained; these patients showed significant improvement in postoperative perimetry. Five patients had some loss of vision, which made it impossible to obtain preoperative visual fields. CONCLUSION: Relaxation of the scleral ring of the prelaminar and laminar regions of the optic nerve head reduces constriction and may prevent necrosis of salvageable but underperfused nerve fibers. Despite improvement of visual acuity in our patients, transvitreal optic neurotomy should be considered experimental, requiring a randomized clinical trial.

Adult↗
PubMedDate not supplied

Bilateral anterior ischaemic optic neuropathy due to optic disc drusen.

PURPOSE: To report a case of bilateral anterior ischaemic optic neuropathy due to buried optic disc drusen. METHODS: Case report. RESULTS: A 64-year-old man presented with swollen optic discs and features suggestive of anterior ischaemic optic neuropathy (AION) in the left and right eye on two separate occasions ten months apart. Detailed ocular examination at presentation and systemic investigations did not reveal an underlying cause for the AION. At a later follow-up, optic disc drusen were noted in both eyes as partial optic atrophy had set in. This was confirmed by ultrasound B scan and demonstration of autofluorescence. CONCLUSIONS: In patients presenting with AION uncommon underlying causes must be considered. Routine ultrasound B scan at presentation can easily establish or exclude optic disc drusen as an underlying cause.

Fluorescein Angiography↗
PubMed2002

Continuing optic nerve atrophy following optic neuritis: a serial MRI study.

To investigate optic neuritis as a model for atrophy in multiple sclerosis (MS) lesions we performed serial magnetic resonance imaging (MRI) on 10 patients with a history of optic neuritis using a fat saturated short-echo fast fluid-attenuated inversion recovery (sTE fFLAIR) sequence. The first study was performed a median of 19.5 months after the onset of optic neuritis and the second 1 year later. Using a computer-assisted contouring technique, a blinded observer calculated the mean area of the intro-orbital optic nerves. The mean area of affected optic nerves decreased over 1 year by 0.9 mm2 from 11.1 to 10.2 mm2 (p = 0.01). Poor visual acuity and decreased visual-evoked potential (VEP) amplitude were associated with atrophy. These findings suggest that atrophy is a feature of focal demyelinating lesions, it may evolve over several years, and may have functional significance. Optic neuritis provides a model to study the effect of inflammatory demyelination through the ability to accurately measure visual function and to visualize and measure the optic nerves using magnetic resonance imaging.

Adult↗
PubMed1999

Optic nerve enhancement on magnetic resonance imaging in arteritic ischemic optic neuropathy.

Although optic nerve enhancement may be seen in magnetic resonance imaging of radiation-induced ischemic optic neuropathy, similar enhancement in ischemic optic neuropathy has not been previously reported in the English-language neuroophthalmologic literature. We report three cases of optic nerve enhancement in biopsy-proven arteritic ischemic optic neuropathy. Clinicians should consider giant cell arteritis in the differential diagnosis of an optic neuropathy with optic nerve enhancement on magnetic resonance imaging.

Aged↗
PubMed2005

[The study on the value of the decompression to the optic nerve channel for the optic atrophy patients].

OBJECTIVE: To evaluate the effective treatment method for the optic nerve atrophy. METHOD: Sixteen patients were diagnosed as optic nerve atrophy by examining the sight, eye base and VEP. There were no occupied lesion in the eye, nose sinus and the intracranial through the CT examination. The visual ability were become worse before the operation. This group of the patients were underwent the eye-nose-ethmoid -sphenoid approach to undergo the decompress of the optic nerve channel. During the operation, the ethmoid was removed and the sphenoid sinus was opened. When the optic nerve channel was found, more than half of it was removed. Then the whole nerve channel was opened. The sheath and the tendon of the optic nerve were opened in longitude direction. The antibiotic, hormone vessel dilation drugs were given. The changes of the visual ability, eye base and VEP between preoperation and postoperation were compared. RESULT: The visual ability and the VEP of 16 cases of the of the patients were improved. A week after the operation and three months latter examination of the eye base showed that ten of the patients got improved and six of them no change. There were no serious postoperative complication. CONCLUSION: The decompression of the optic nerve channel is the ideal method to deal with optic nerve atrophy.

Adult↗
PubMed2006

[Endoscopic optic nerve decompression in traumatic optic neuropathy: analysis of 72 cases].

OBJECTIVE: To review the effects of optic nerve decompression by endoscopic technique in traumatic optic neuropathy. METHODS: Seventy-two patients (73 eyes) with traumatic optic neuropathy which were treated with large dose of glucocorticoid but inefficacious were undergone endoscopic optic nerve decompression. The days from injury to surgery were 1-57 d. Among that, < or = 3 d 15 cases, 4-7 d 37 cases, 8-10 d 9 cases, 11-15 d 5 cases, 16-30 d 5 cases, >30 d 1 cases. The vision of pro-operation: with light perception or higher grades 18 eyes; with no light perception 55 eyes. RESULTS: All patients were followed up for more than 3 months. Fourty-six of 73 eyes had improvements in visual acuity, the total effective rate was 63.01%. Thirty-one of 55 eyes with no light perception had raises in visual acuity (56.36%). Fifteen of 18 eyes with light perception or higher grades had improvements (83.33%). No complication had happened. CONCLUSIONS: Endoscopic optic nerve decompression is an appropriate technique for patients with traumatic optic neuropathy. Even though the patient has injured in longer time and high-dose steroid treatment has failed, optic nerve decompression may improve visual acuity.

Adolescent↗
PubMedDate not supplied

Chemical shift selective magnetic resonance imaging of the optic nerve in patients with acute optic neuritis.

Optic neuritis is often the first manifestation of multiple sclerosis (MS). Sixteen patients with acute optic neuritis and one patient with benign intracranial hypertension (BIH) were investigated by magnetic resonance imaging, using a chemical shift selective double spin echo sequence. In 3 of the 16 patients, abnormalities were seen. In one patient with bilateral symptoms, signal hyperintensity and swelling of the right side of the chiasm were found. In another patient the optic nerve was found diffusely enlarged with only a marginally increased signal in the second echo. In the third patient an area of signal hyperintensity and swelling was seen in the left optic nerve. In the patient with BIH the subarachnoid space which surrounds the optic nerves was enlarged. Even using this refined pulse sequence, avoiding the major artefact in imaging the optic nerve, the chemical shift artefact, lesions were only shown in 3/16 (19%) of the patients with optic neuritis. Nevertheless, the presented chemical shift selective double spin echo sequence may be of great value for detection of retrobulbar lesions.

Acute Disease↗
PubMed1982

Indirect imaging of the canine optic nerve, using metrizamide (optic thecography).

Between the optic nerve and its sheath is a small, CSF-filled space that communicates with the subarachnoid space of the brain. A technique for the radiographic opacification of the optic nerve subarachnoid space following the intrathecal injection of metrizamide was investigated in 8 dogs. The technique enabled indirect visualization of the optic nerves from the optic chiasm to the eyeball and of structures within the subarachnoid basal cisterns of the brain, including the optic chiasm, hypophysis, and blood vessels of the cerebral arterial circle. Displacement and obstruction of the optic nerve subarachnoid space were demonstrated after surgically creating optic nerve lesions to simulate orbital tumors and trauma. The technique was found to be safe, effective, and advantageous over other techniques currently available for the visualization of these structures.

Animals↗
PubMed2004

[Automated imaging of the optic nerve and optic nerve fibers is essential to daily clinical practice].

Chronic open-angle glaucoma is a progressive optical neuropathy. Automated imaging of the optic disc and optic nerve fibers provides reliable analysis of the optic nerve as well as long-term follow-up of neuropathy patients. HRT, GDX-VCC, and OCT, which analyze the optic disc and optical fibers, provide indisputable assistance in improving screening techniques and the follow-up of progressive glaucoma.

Chronic Disease↗
PubMed1999

Optic glioma with characteristic bilateral optic atrophy in a 3-year-old girl.

We report a case of optic glioma with bilateral optic atrophy. A 3-year-old girl presented with vomiting and left hemiparesis. She had hypothalamic dysfunction, right ptosis, right monocular nystagmus, left facial palsy, left hemiparesis, and left pes adductus. Neuroimaging studies showed obstructive hydrocephalus with a large suprasellar calcified tumor with a ring-like enhancement mimicking craniopharyngioma. Visual-evoked potentials showed delayed latency of N75 in the right occipital lead. The tumor, a pilocytic astrocytoma in the right optic tract and chiasma, was partially removed via a right frontotemporal craniotomy. The right optic nerve had shrunk to half the normal diameter and became twisted downwardly. Intracranial pressure (ICP) increased to 40 cm H2O. The fundus had bilateral optic atrophy without disc swelling. To our knowledge, this is the first report of a lamina/dot sign of the optic disc in a small child with a brain tumor and a normal neuroretinal fiber layer. These ocular findings may result from possible interruption of the axonal flow caused by the tumor and not increased ICP.

Child, Preschool↗
PubMed1980

Ontogeny of the retina and optic nerve in Xenopus laevis. II. Ontogeny of the optic fiber pattern in the retina.

The ontogeny of optic fiber patterns within the Xenopus laevis retina has been studied in silver-stained serial sections and whole mounts. Ganglion cell axons ("pioneers") appear much earlier than previously recognized, at Nieuwkoop-Faber ('56) Stage 28. Fibers fasciculate into bundles as they arise in the retina and reach the chiasma by NF Stage 32. Because the retina grows in rings at its margins, ganglion cell axons differentiate at the periphery and join the nearest fiber bundles (fascicles) to reach the optical disc. A radial fascicle pattern develops by Stage X (Grant et al., '80) within the optic fiber layer of the retina and acts as a template of pathways that lead all later appearing fibers out of the retina. Since the retina grows asymmetrically along its dorso-ventral axis, the fascicle pattern develops asymmetrically, with dorsal quadrant fascicles forming an arcuate pattern in contrast to shorter, thicker ventral quadrant fascicles. The growth pattern of the retina and the "principle" of fiber following suggest that "positional information" is acquired by ganglion cells according to a system of polar coordinates (MacDonald, '77). A radial distance "r" from the center is determined temporarily by ganglion cell birthday and an angular value "theta" is given by the angular position of the fascicle followed by its axons to the optical disc. Wedges of ganglion cells send their axons into a common fascicle which retains its integrity as it leaves the retina at the optic disc. This pattern of optic fiber development suggests a model for retino-topic ordering of the optic fiber projection in Xenopus, with the fascicle acting as the "pattern-forming unit of connectivity."

Animals↗
PubMed1993

Developmental changes in the optic nerve related to ethanol consumption in pregnant rats: analysis of the ethanol-exposed optic nerve.

Visual impairment is one of the most common ophthalmic abnormalities in fetal alcohol syndrome. Pathologic changes in optic nerve development related to alcohol consumption could be involved in this dysfunction. In order to assess the consequences of pre- and postnatal exposure to alcohol on the developing optic nerve, we administered an ethanol-containing liquid diet (5% w/v) before and during gestation and throughout lactation to rats and their offspring. A group of control animals were kept on a pair-fed isocaloric diet. The optic nerves were obtained at key stages from fetuses (21 days of gestation) and pups (4, 7, 14, 21 and 28 postnatal days). Samples of the optic nerve cross-section, behind the eyeball, were processed for analysis of gliogenesis, myelinogenesis, axonal growth, and remodelling events, using light and electron microscopy. Qualitative, morphometric, and immunocytochemical analyses, alternatively using anti-GFAP and anti-MBP antibodies, were carried out. Optic nerve cross-sections from prenatal and postnatal alcohol-exposed rats showed a decrease in size. Ultrastructural alterations and retarded development in macroglial cells, optic axons, and myelin sheath were also observed. The most prominent abnormalities were: damage of cytoplasmic organelles and disorganization of cytoskeleton in astrocytes; a decrease in free ribosome density and nuclear membrane inclusions in oligodendrocytes; and fragmentation of lamellae, aberrant myelin sheaths and intralamellar inclusions in myelin. These findings suggest that alcohol abuse during pregnancy is teratogenic to the optic nerve and closely related to the altered visual function.

Abnormalities, Drug-Induced↗
PubMed1982

Measurement of the optical density of the optic nerve head I: the pallor of the papilla in artificial ocular hypertension.

The pallor of the optic disc during acute raise of intraocular pressure can be shown on the negatives of orthochromatic film and is measured by a photoscanner. When raising intraocular pressure from normal values to ablut 40 mm Hg, ten young persons showed an increase in optical density from 0.28 log units +/- 0.04 SEM to 0.38 log units +/- 0.04 SEM. When raising IOP to 65 mm Hg, the optical density was 0.43 log units +/- 0.04; with 110 mm Hg the optical density was 0.44 log units +/- 0.04 SEM. Above values of 40 mm Hg IOP, the pallor does not remain constant but may also decrease in some cases. The higher the intraocular pressure, the more contradictory the response. The phenomenon may be shown on various parts of the rim simultaneously. The amount of maximum pallor is directly related to the value of optical density with normal intraocular pressure. After restoring IOP to normal values, optical density decreases again, the amount of decrease being related to initial value. The contradictory response with higher IOP may be due to autoregulation of the capillaries of the optic nerve head.

Humans↗
PubMed1996

Optic coherence tomography of optic disk pit maculopathy.

PURPOSE: To define the structure of optic disk pit maculopathy. METHODS: A patient was examined with optic coherence tomography before and after an intravitreal gas tamponade. RESULTS: Before intravitreal gas injection, optic coherence tomography defined a separation between the inner and outer layers of the retina that connected with the optic disk pit. An outer retinal layer detachment that centered on the fovea was also present. After pneumatic displacement of the intraretinal and subretinal fluid, optic coherence tomography disclosed that the two layers were opposed and in contact with the retinal pigment epithelium. CONCLUSIONS: Optic coherence tomography confirmed the two-layer structure of optic disk pit maculopathy and demonstrated the positive effect of pneumatic displacement.

Humans↗
PubMed1996

Optical coherence tomography of macular lesions associated with optic nerve head pits.

PURPOSE: Although optic pits were described more than a century ago, the pathogenesis and pathologic nature of the associated macular lesions remain controversial. The authors used the technique of optical coherence tomography (OCT) to further define the anatomic relation that exists between optic pits, macular schisis-like spaces, and macular detachments. METHODS: Four eyes of three consecutive patients with optic pit-related macular pathology were evaluated. Cross-sectional OCT images were correlated with findings from slit-lamp biomicroscopy and stereo fundus photography. All eyes previously had undergone unsuccessful photocoagulation to the temporal juxtapapillary retina. One eye had undergone vitrectomy and intraocular gas tamponade, resulting in partial resorption and displacement of the submacular fluid. RESULTS: Retinal edema and cystic degeneration were present, overlying macular neurosensory detachments in all four eyes. The most prominent edema was present in the outer retina at the level of the outer plexiform layer. This mimicked a true retinoschisis cavity, although bridging retinal elements were identifiable. A lesser degree of edema was present in the inner retina, predominantly located between the disc and fovea. In one eye, a lamellar hole was shown to be a defect in the outer neurosensory retina. In another eye, a macular detachment developed under a pre-existing schisis-like cavity. The schisis-like cavity or edematous retina communicated with the optic disc in all eyes, whereas none of the eyes demonstrated a direct connection between the macular detachment and optic pit. CONCLUSION: These findings support the concept of a bilaminar structure in which a macular detachment develops secondarily to a pre-existing schisis-like lesion consisting of severe outer retinal edema. Fluid may enter from the optic pit into the retinal stroma and not directly into the subretinal space, explaining the prolonged recovery and frequency of treatment failure after photocoagulation to the juxtapapillary retina.

Adult↗