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  • straylight  (5)
  • glare  (3)
  • vasoactive intestinal polypeptide
  • Key words Liver transplantation
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  • 1
    ISSN: 1573-2622
    Keywords: Diaphany ; translucency ; straylight ; glare ; light scatter ; X-linked megalocornea ; contrast sensitivity ; visual optics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intraocular straylight can be measured, in clinical as well as normal cases, by the direct compensation technique. Intraocular straylight is known to originate from the cornea, lens and fundus. We have studied a fourth source: the translucency of the iris and surrounding ocular wall. For lightly-pigmented normal eyes this source proved to be important. In the present paper results are reported from a patient with X-linked megalocornea. He had diaphany of the iris, as is common in these patients, and photophobic complaints. Quantitative measurements showed that the translucency was much increased so that the intraocular straylight was far above the normal level.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Documenta ophthalmologica 78 (1991), S. 161-167 
    ISSN: 1573-2622
    Keywords: Intraocular implant lenses ; IOL ; non-monofocal lenses ; bifocal lenses ; multifocal lenses ; diffraction lenses ; modulation transfer function ; contrast sensitivity function ; straylight ; glare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Non-monofocal IOLs are designed to give simultaneously sharp images of distant and near objects. This is achieved by means of different focal distances for various portions of the light reaching the eye. As a result, for any given object, one part of the light will be properly focused, while another part is out of focus. This results in a sharp image superposed on a blurred image, causing contrast loss. The retinal contrast loss as a function of spatial frequency is derived in this paper.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Documenta ophthalmologica 78 (1991), S. 177-181 
    ISSN: 1573-2622
    Keywords: Glare ; straylight ; contrast sensitivity ; light scatter ; disability glare ; discomfort glare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An overview is given of the basic phenomena that may lead to glare complaints in patients. Prominent among them is increased intraocular straylight; this can be measured. Other causes may include: increased sensitivity to normal straylight, the length of (increased) light and dark adaptation times, (small angle) neuronal lateral interaction. Distinction must be made between disability glare and discomfort glare. Tests have been proposed to determine glare-induced loss of various visual functions. Often the test results are thought to be directly related to straylight but this may be untrue.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Documenta ophthalmologica 61 (1986), S. 327-333 
    ISSN: 1573-2622
    Keywords: stray light ; glare ; contrast sensitivity ; cataract ; corneal dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract For healthy eyes intraocular light scatter was investigated several decades ago. For pathological eyes, however, little is known. As clinical test several techniques have been proposed but none has gained general acceptance. A disadvantage of these tests was that quantities were estimated that related only indirectly to the amount of light scatter. We propose a method that gives a direct estimate of the light scatter. We studied patients with cataract, corneal dystrophy, iris and fundus hypopigmentation, etc. A remarkable finding was that visual acuity correlates rather weakly with the amount of scatter. Since, however, the amount of scatter causes a considerable loss of visual function, the results show that for these patients the visual acuity test gives a rather limited impression of their visual handicap. More attention to the problems associated with intraocular light scatter is needed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-2622
    Keywords: luminance electroretinogram ; pattern electroretinogram ; point-spread function ; straylight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It is generally accepted that the pattern electroretinogram for very large spatial elements is the result of local luminance stimulation. Responses due to the luminance differences between elements may be assumed to be relatively unimportant because in the case of large elements only few retinal units are stimulated by gradients. With decreasing pattern element size one wonders to what extent the electroretinogram continues to be based on the local luminance stimulation. We investigated this question using 8 Hz checkerboard reversal and compared the pattern recordings with the recordings resulting from the same stimulus field modulated homogeneously (focal electroretinogram). A 100% modulated checkerboard at retinal level may be considerably less modulated because of imperfect optics of the eye. So the pattern electroretinogram should be compared with homogeneous field stimulation of correspondingly lower modulation depth. On the basis of the optical transfer properties of the eye we compared by subtracting the proper focal electroretinogram from the pattern electroretinogram. The difference response was virtually zero for check sizes larger than 120′. For checks from 60′ down the difference response was of the same order of magnitude as the adjusted focal recording. This difference response for eyes with normal optics is largest around 30′; its wave form was found to be rather invariant with check size.
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  • 6
    ISSN: 1573-2622
    Keywords: luminance electroretinogram ; pattern electroretinogram ; point-spread function ; straylight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In studies on the pattern electroretinogram the quality of the retinal image is a major concern. The use of contact lens electrodes was rejected since a good pattern could not be recorded. This is believed to be due to blurring of the retinal image. As indicator of image quality the patient's visual acuity is often used. We wondered whether this is a sufficient criterion. The retinal image is the product of the whole optical point-spread function of the eye whereas visual acuity refers only to the central portion of this function. On the basis of existing reports it can be estimated that for the young normal eye the outer edges of this function (straylight) causes considerable loss of contrast. The strength of the straylight can be much greater in older eyes. We studied the relation between the point-spread function including straylight and the pattern electroretinogram in normal eyes and some pathological cases. The measurements proved to follow the calculated contrasts on the basis of a local luminance model, with the exception of enhancement (tuning) around 60′ checksize for the young normal eye. Because of the considerable differences in straylight in an older population one has to take into account that loss of pattern electroretinogram can be suffered in patients with otherwise good visual acuity.
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  • 7
    ISSN: 1619-1560
    Keywords: sweat gland ; substance P ; vasoactive intestinal polypeptide ; diabetic neuropathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Vasoactive intestinal polypeptide (VIP) and substance P (SP) immunoreactivity are reduced in the cutaneous nerves of diabetic patients with peripheral neuropathy. The functional significance of this finding was studied by measuring the forearm sweat response to intradermal methacholine and the effect of coadministration of VIP and SP in six normal subjects, and in six diabetic patients with neuropathy and eight without. Flare responses to the two peptides were also measured. Methacholine-induced sweat output was significantly greater in neuropathic patients compared with the other groups (p 〈 0.05), suggesting upper limb denervation supersensitivity. VIP and SP alone did not evoke sweating in any subject. Injection of VIP or SP reduced methacholine-induced sweating to a similar degree in all groups, except that the reduction was smaller in the nonneuropathic group than in the others (p = 0.028 versus normal subjects, p = 0.014 versus neuropathic diabetic patients). Flare responses to the peptides were markedly reduced in the neuropathic patients compared with the other groups (p 〈 0.01). In neuropathic patients, increased sweat responses and decreased flare coexist with diminished neurophysiological measurements; cutaneous sweating and flare responses provide valuable additional information to conventional methods of neurological assessment in diabetic neuropathy.
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  • 8
    ISSN: 1432-2277
    Keywords: Key words Liver transplantation ; Hepatitis C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The optimal immunosuppressive regimen in patients transplanted for hepatitis C (HCV) is still under discussion. High immunosuppression may promote viral replication and recurrent graft hepatitis. But acute and chronic rejection frequently seen in conjunction with HCV recurrence may require some rescue therapy. One hundred and thirty-seven patients transplanted for HCV cirrhosis, who were HCV-RNA positive prior to transplantation, were analyzed. Seventy-nine patients received CSA-based immunosuppression and 58 patients FK506-based immunosuppression. One-month patient survival was 100 % in both groups. Three month and 1-year survival rates and the cumulative 1–5-year patient survival was similar in CsA-treated [67/79 (84.8 %)] and FK506-treated patients [50/58 (86.2 %)]. Retransplantations for HCV recurrence were performed in 5.1 % of CsA-treated patients and 6.9 % of FK506-treated patients; it was successful in 50 % and 75 % of patients, respectively. Conversion from CsA to FK506 and vice versa was high with 25 out of 79 patients (31.6 %) converting in the CsA group and 8 out of 58 patients (13.8 %) converting in the FK506 group. Conversion to FK506 was performed due to acute and chronic rejection and to CsA because of toxicity and HCV recurrence. In both groups, 25 % of converted patients died. Five patients of the CsA group and 9 of the FK506 group received OKT3; more than one-third of each group died. Five patients in the CsA group and 6 in the FK506 group received mycophenolate mofetil (MMF) for HCV recurrence or acute and chronic rejection in conjunction with HCV recurrence. All patients of this critical group are alive with good graft function. In conclusion, survival rates of HCV patients were similar to those seen for other indications. Conversion from CsA to FK506 and vice versa was high and reflects a critical group concerning patient survival. OKT3 treatment should be avoided. A promising therapeutic option for critical patients experiencing acute or chronic rejection in conjunction with HCV recurrence may be treatment with MMF.
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