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At least 739 records · Page 41Linked to original sources
PubMed1986

Familial optic atrophy with sex-influenced severity. A new variety of autosomal-dominant optic atrophy?

A family is described with 20 members in three successive generations affected by optic atrophy without other ocular or extraocular manifestations. The anomaly was transmitted as an autosomal-dominant character. There was a clearly bimodal distribution of severity: 4 male patients complained of severe impairment of vision since childhood while 16 other subjects (7 males and 9 females) were completely asymptomatic. This family could be an example of a new variety of autosomal dominant optic atrophy characterized by sex-influenced severity.

Adolescent↗
PubMed1996

Cerebrospinal fluid in acute optic neuritis: experience of the optic neuritis treatment trial.

The Optic Neuritis Treatment Trial (ONTT) is a prospective study of corticosteroid treatment of acute optic neuritis (ON), with subsequent longitudinal follow-up to determine development of clinically definite multiple sclerosis (CDMS). We analyzed the CSF of 83 patients with clinically isolated ON who underwent lumbar puncture within 24 hours of enrollment into the ONTT to determine the value of CSF changes in ON, especially regarding diagnostic utility, immunologic changes, MRI correlations, and progression to CDMS. All patients had baseline MRI scans graded for changes typical of MS. CSF measurements included immunoglobulin G (IgG) synthesis, IgG ratio, myelin basic protein, IgG kappa light chains, and oligoclonal banding. No patients had their diagnosis or management altered as a result of CSF findings. Except for oligoclonal bands, few patients showed any abnormalities on CSF tests, and no tests correlated with the 2-year development of CDMS. Oligoclonal banding, present at baseline in 11 of 13 patients who developed CDMS, did predict progression to CDMS, but this was not independent of MRI abnormalities. Two patients with oligoclonal bands and a normal MRI did progress to CDMS. We conclude that CSF analysis may not be necessary in the routine evaluation of patients presenting with a typical clinical profile of acute ON, and that most CSF tests add little additional information to MRI results for predicting the 2-year development of CDMS. However, the precise role of oligoclonal banding in the analysis of such patients awaits longer follow-up of this cohort.

Administration, Oral↗
PubMed2003

Optical bioimaging: from living tissue to a single molecule: optical detection of synaptically induced glutamate transporter activity in hippocampal slices.

Since voltage-sensitive dyes (VSDs) change their optical properties in response to membrane potential changes, non-invasive optical measurements of membrane excitation using VSDs have been applied to various types of excitable tissue. This article deals with the authors' recent work using this technique in addition to basic and technical information about VSD imaging. By applying this technology to hippocampal brain slices, we have found that astrocytes play indispensable roles in sequestering glutamate, maintenance of synaptic transmission, and neuronal survival. Finally, the potential of VSD imaging for drug development was discussed.

Amino Acid Transport System X-AG↗
PubMed2002

Large-aperture automatic focimeter for the measurement of optical power and other optical characteristics of ophthalmic lenses.

We propose an optical apparatus enabling the measurement of spherical power, cylindrical power, and optical center coordinates of ophthalmic lenses. The main advantage of this new focimeter is to provide a full bidimensional mapping of the characteristics of ophthalmic glasses. This is made possible thanks to the use of a large-area and high-resolution position-sensitive detector. We describe the measurement principle and present some typical mappings, particularly for progressive lenses. We then discuss the advantages in terms of speed and versatility of such a focimeter for the measurement of complex lens mappings.

Equipment Design↗
PubMed2005

Multiple scattering in optical coherence tomography. II. Experimental and theoretical investigation of cross talk in wide-field optical coherence tomography.

We present a comprehensive study of multiple-scattering effects in wide-field optical coherence tomography (OCT) realized with spatially coherent illumination. Imaging a sample made of a cleaved mirror embedded in an aqueous suspension of microspheres revealed that, despite temporal coherence gating, multiple scattering can induce significant coherent optical cross talk. The latter is a serious limitation to the method, since it prevents shot-noise-limited detection and diffraction-limited imaging in scattering samples. We investigate the dependence of cross talk on important system design parameters, as well as on some relevant sample properties. The agreement between theoretical and experimental results for the wide range of parameters investigated was very good, in both the lateral and the axial dimensions. This further confirms the validity of the model developed in our companion paper [J. Opt. Soc. Am. A 22, 1369-1379 (2005)].

Algorithms↗
PubMed2004

Adaptive-optics ultrahigh-resolution optical coherence tomography.

Merging of ultrahigh-resolution optical coherence tomography (UHR OCT) and adaptive optics (AO), resulting in high axial (3 microm) and improved transverse resolution (5-10 microm) is demonstrated for the first time to our knowledge in in vivo retinal imaging. A compact (300 mm x 300 mm) closed-loop AO system, based on a real-time Hartmann-Shack wave-front sensor operating at 30 Hz and a 37-actuator membrane deformable mirror, is interfaced to an UHR OCT system, based on a commercial OCT instrument, employing a compact Ti:sapphire laser with 130-nm bandwidth. Closed-loop correction of both ocular and system aberrations results in a residual uncorrected wave-front rms of 0.1 microm for a 3.68-mm pupil diameter. When this level of correction is achieved, OCT images are obtained under a static mirror configuration. By use of AO, an improvement of the transverse resolution of two to three times, compared with UHR OCT systems used so far, is obtained. A significant signal-to-noise ratio improvement of up to 9 dB in corrected compared with uncorrected OCT tomograms is also achieved.

Equipment Design↗
PubMed2004

Acousto-optic differential optical absorption spectroscopy for atmospheric measurement of nitrogen dioxide in Hong Kong.

Measurement of the atmospheric concentration of nitrogen dioxide (NO(2)) pollutant was demonstrated by differential optical absorption spectroscopy (DOAS) using a visible acousto-optic tunable filter. In a traditional spectral scanning DOAS system for atmospheric concentration monitoring, a highly stable light source is required. When the light intensity fluctuates during scanning, the concentration retrieval will be inaccurate. In order to reduce the error due to intensity fluctuations, a modified DOAS system has been developed by introducing a broadband light intensity monitoring channel. Using the measured intensity of the broadband channel as the intensity of the light source, the spectrum can be de-biased and the residual intensity variation will primarily result from atmospheric extinction. In addition, by employing the lock-in detection technique, the background light interference is also removed in the modified DOAS system. The atmospheric NO(2) concentration measurement was performed at the campus of City University of Hong Kong, and the results were compared with the concentration reported from a nearby monitoring station in Sham Shui Po, operated by the Hong Kong Environmental Protection Department.

Absorption↗
PubMed1988

Evidence of orbital deformation in indirect optic nerve injury. Weight lifter's optic neuropathy.

A 16-year-old boy developed monocular visual loss due to optic neuropathy following frontal head trauma. His trauma was unique in that it consisted of a static loading force to the brow, rather than the dynamic impact more commonly associated with blunt orbital injuries. This case demonstrates the role of isolated deformation of orbital bones in the pathogenesis of indirect optic nerve injury.

Adolescent↗
PubMed2006

[Influence of "optical illusion" on detectability in diagnosis for head CT images: participation of optical illusion of light perception in medical image reading and diagnosis].

Even if the visual impression of the photographic density of the brain in head CT images is shown as physically the same, it is known that optical illusions of lightness perception (assimilation, contrast, picture frame effect, etc.) occur and that practical density can be observed psychologically differently, according to differences in the color of the skull and background, and differences in cases (differences in picture pattern). Therefore, in this study, in order to clarify the influence of optical illusion on detectability in diagnosis, the author attempted to compare detectability in four sample cases, consisting of acute cerebral infarction (1), acute epidural hematoma (1), and chronic subdural hematoma (2), using visual subjective evaluation. In the case of acute cerebral infarction, there was no significant difference in detectability between the original image and the virtual images. Further, it clarified that the original head CT image (acute epidural hematoma) with the high-density hematoma recognized at the marginal limited part of the brain was inferior to virtual images in detectability, while it clarified that the original head CT image (chronic subdural hematoma) with the low-density hematoma was superior to virtual images in detectability, because of visual psychological emphasis on the difference of the film contrast between the hematoma and white skull.

Brain↗
PubMed1998

[Trans-ethmoidal optic nerve decompression in traumatic optic neuropathy].

UNLABELLED: To evaluate the outcome of trans-ethmoidal optic nerve decompression (TOND). METHOD: Between November 1984 and May 1996, 35 patients with traumatic optic neuropathy (TON) underwent TOND. While 6 patients were treated with high dose corticosteroids (HDC). RESULTS: 13(37.14%) cases of 35 patients who underwent TOND showed improvement in vision. 1 (16.67%) of 6 patients who were treated with HDC showed improvement in vision. Of the 12 patients with some initial vision, 8 patients underwent TOND and 7(87.5%) patients showed improvement in vision. Another 4 patients treated with HDC, 1(25.0%) patient showed improvement in vision. Of the 29 patients who presented with no light perception, 27 patients underwent TOND and 6(22.22%) patients showed improvement in vision. 2 patients treated with HDC failed to get vision improvement. CONCLUSION: TOND can improve vision in patients with TON. It is rational to perform surgical decompression early. Using of HDC before and after surgery may improve the outcome of TON. No light perception and absence of waveform on visual evoked response is not contradict, some patients may show improvement in vision.

Adolescent↗
PubMedDate not supplied

[Optic coherent tomography: a new high-resolution technology of visualization of tissue structures. Communication II. Optical images of benign and malignant entities].

This is the second communication of a series of publications on Russian studies in the field of optical coherent tomography (OCT), the newest noninvasive highly resolving technology of visualization of the structure of biological tissues. By using the investing tissues as an example, this paper demonstrates the universal types of changes in their optical properties. Optimal images permit differentiate benign and malignant processes with a high degree of diagnostic accuracy. Diverse benign processes occurring in the epithelium are detected on the OCT images as changes in its height, the scattering properties and stroke of a basilar membrane. The absence of any structure on the image is the main OCT criterion for malignancy. The diagnostic efficiency of OCT is high in recognizing neoplasia of various mucous membranes: the sensitivity of the technique is 77-98%; its specificity and diagnostic accuracy are 71-96 and 81-87%, respectively.

Adult↗
PubMed2005

[Optical biopsy of the retina in vivo: on optical coherence tomography and its clinical use in ophthalmology].

Optical Coherence Tomography (OCT) is a novel, non invasive imaging method, which enables in vivo assessment of living tissues, providing near histological resolution images. The first description of its clinical introduction was in ophthalmology, which substantially changed our view of specific retinal diseases. OCT technology is slowly penetrating into other medical fields, supposedly opening new perspectives with the possibility of in vivo optical biopsy. The aim of this paper is to review the clinical use of OCT, with special emphasis on ophthalmology.

Animals↗
PubMed1991

Optic atrophy in Leber hereditary optic neuroretinopathy is probably determined by an X-chromosomal gene closely linked to DXS7.

Leber hereditary optic neuroretinopathy (LHON) is a maternally inherited disease, probably transmitted by mutations in mtDNA. The variation in the clinical expression of the disease among family members has remained unexplained, but pedigree data suggest an involvement of an X-chromosomal factor. We have studied genetic linkage of the liability to develop optic atrophy to 15 polymorphic markers on the X chromosome in six pedigrees with LHON. The results show evidence of linkage to the locus DXS7 on the proximal Xp. Tight linkage to the other marker loci was excluded. Multipoint linkage analysis placed the liability locus at DXS7 with a maximum lod score (Zmax) of 2.48 at a recombination fraction (theta) of .0 and with a Zmax - 1 support interval theta = .09 distal to theta = .07 proximal of DXS7. No evidence of heterogeneity was found among different types of families, with or without a known mtDNA mutation associated with LHON.

Adult↗
PubMed1979

Elimination of cobalt from the frog brain introduced into the optic centres through the optic nerve.

One optic nerve in several frogs was filled with cobaltous-lysine complex, and the animals were left to survive from 1 day to 52 days. Degenerated cobalt-filled retinal fibres were phagocytosed by ependymo-glial, and microglial cells. The cobalt appeared in the ependymo-glial cells in the 4th postoperative day, and its amount was greatly reduced by the 52nd day. Within 12 days the labelled axons were replaced by cobalt-loaded microglial cells in the termination sites of optic fibres. By the end of the experimental period, the number of labelled cells increased in the periventricular layers, and decreased in places where retinal fibres had terminated. These processes were accompanied by the appearance of cobalt in the choroid plexus. It is supposed that glial cells dischargd the cobalt into brain ventricles, and the metal left the nervous tissue via the cerebrospinal fluid.

Animals↗
PubMed1994

Outcomes of optic nerve sheath decompression for nonarteritic ischemic optic neuropathy.

Efficacy of optic nerve sheath decompression (ONSD) in treating non-arteritic ischemic optic neuropathy (NAION) is not clear. We retrospectively analyzed the records of 91 patients with NAION, who were examined during a two-year period, and compared the final Snellen visual acuities of eyes treated with ONSD with those of eyes that did not have surgery. Seven of 18 eyes with ONSD (39%) demonstrated increased visual acuity of two or more lines; whereas 23 of 71 eyes without surgery (32%) had increased acuity. The ONSD group and no surgery group were further subdivided into eyes with progressive visual loss and nonprogressive visual loss. No statistically significant differences in visual outcome between groups were found. We did not find the high frequency of visual improvement that has been reported in some studies of ONSD for NAION.

Adult↗
PubMedDate not supplied

Evaluation of an optical system in the fibercolonoscope: trial manufacture of an instrument with 30 degrees deviation optical system.

To evaluate the best optical system for colonoscopy a colonofibrescope was manufactured in which the optical system had a 30 degrees prograde deviation. In this test model, frontal view was easily obtained and close-up observations were possible. At areas with prominent semilunar folds, the zone behind them also came into full view. The bowel lumen could be visualized by angulation, the same as with conventional instruments. The passage trough the sigmoid-descending junction was easy, and visualization or the colon up to the distal transverse colon was accomplished within a short time in the majority of cases without fluoroscopic control.

Colonic Diseases↗